Federal Register, Volume 74 Issue 41 (Wednesday, March 4, 2009)

[Federal Register Volume 74, Number 41 (Wednesday, March 4, 2009)]
[Proposed Rules]
[Pages 9478-9520]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-4500]

[[Page 9477]]

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Part II

Department of Transportation

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National Highway Traffic Safety Administration

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49 CFR Part 571

Federal Motor Vehicle Safety Standard; Rearview Mirrors; Proposed Rule

Federal Register / Vol. 74, No. 41 / Wednesday, March 4, 2009 /
Proposed Rules

[[Page 9478]]

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. NHTSA-2009-0041]
RIN 2127-AK43

Federal Motor Vehicle Safety Standard; Rearview Mirrors

AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation (DOT).

ACTION: Advance notice of proposed rulemaking (ANPRM).

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SUMMARY: This document initiates rulemaking to amend Federal Motor
Vehicle Safety Standard (FMVSS) No. 111, Rearview Mirrors,\1\ to
improve a driver's ability to see areas to the rear of a motor vehicle
in order to mitigate fatalities and injuries associated with backover
incidents. The agency and Congress are concerned that vehicles have
``blind zones,'' \2\ areas behind the vehicle in which drivers may have
difficulty seeing and avoiding a person or other obstacle. Through this
notice, NHTSA presents its initial research efforts and solicits
additional information that will enable the agency to develop an
effective proposal to mitigate backover incidents related to vehicle
rear blind zones.
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\1\ 49 CFR 571.111, Standard No. 111, Rearview Mirrors.
\2\ We note that this is different than what many people
informally call a ``blind spot,'' a term used to describe an area to
the side of the car where people may not be able to see a vehicle
when changing lanes.

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DATES: Comments must be received on or before May 4, 2009.

ADDRESSES: You may submit comments to the docket number identified in
the heading of this document by any of the following methods:
Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the online instructions for submitting
comments.
Mail: Docket Management Facility: U.S. Department of
Transportation, 1200 New Jersey Avenue, SE., West Building Ground
Floor, Room W12-140, Washington, DC 20590-0001.
Hand Delivery or Courier: 1200 New Jersey Avenue, SE.,
West Building Ground Floor, Room W12-140, between 9 a.m. and 5 p.m. ET,
Monday through Friday, except Federal holidays.
Fax: 202-493-2251
Instructions: For detailed instructions on submitting comments and
additional information on the rulemaking process, see the Public
Participation heading of the SUPPLEMENTARY INFORMATION section of this
document. Note that all comments received will be posted without change
to http://www.regulations.gov, including any personal information
provided. Please see the Privacy Act heading below.
Privacy Act: Anyone is able to search the electronic form of all
comments received into any of our dockets by the name of the individual
submitting the comment (or signing the comment, if submitted on behalf
of an association, business, labor union, etc.). You may review DOT's
complete Privacy Act Statement in the Federal Register published on
April 11, 2000 (65 FR 19477-78) or you may visit http://DocketInfo.dot.gov.
Docket: For access to the docket to read background documents or
comments received, go to http://www.regulations.gov or the street
address listed above. Follow the online instructions for accessing the
dockets.

FOR FURTHER INFORMATION: For technical issues: Ms. Elizabeth Mazzae,
Vehicle Research and Test Center, Telephone: (937) 666-4511. Facsimile:
(202) 366-3171. For legal issues: Ari Scott, Office of Chief Counsel,
Telephone (202) 366-2992. Facsimile: (202) 366-3820. You may send mail
to these officials at: The National Highway Traffic Safety
Administration, Attention: NVS-010, 1200 New Jersey Avenue, SE.,
Washington, DC 20590.

SUPPLEMENTARY INFORMATION:

I. Executive Summary
II. Cameron Gulbransen Kids Transportation Safety Act of 2007
III. Existing Regulatory Requirements for Rear Visibility
A. U.S.
B. Other Countries
IV. Backover Safety Problem
A. Injuries and Fatalities in Backing Incidents
B. Vehicle Type Involvement in Backing Incidents
C. Age Involvement in Backing Incidents
D. SCI Backover Case Summary
E. Assessment of Backover Crash Risk by Pedestrian Location
V. Technologies for Improving Rear Visibility
A. Rear-Mounted Convex Mirrors
B. Rearview Video Systems
C. Sensor-Based Rear Object Detection Systems
D. Multi-Technology (Sensor + Video Camera) Systems
E. Future Technologies
F. Summary and Questions Regarding Technologies for Improving
Rear Visibility
VI. Drivers' Use and Associated Effectiveness of Available
Technologies to Mitigate Backovers
A. Rear-Mounted Convex Mirrors
B. Rearview Video Systems
C. Sensor-Based Rear Object Detection Systems
D. Multi-technology (Sensor + Camera) Systems
E. Summary
F. Questions
VII. Rear Visibility of Current Vehicles
VIII. Relationship Between Rear Visibility and Backing/Backover
Crashes
IX. Options for Mitigating Backover Incidents
A. Approaches for Improving Vehicles' Rear Visibility
B. Cost Benefit Scenarios
C. Questions
X. Options for Measuring a Vehicle's Rear Visibility
A. Rear Visibility Measurement Procedures
B. Rear Visibility Measurement Method Variability
C. Comparison of Human-Based Versus Laser-Based Rear Visibility
Measurement Protocols
D. Input From Industry Regarding Rear Visibility Measurement
E. Questions
XI. Options for Assessing the Performance of Rear Visibility
Countermeasures
A. Countermeasure Performance Test Object
B. Countermeasure Performance Test Area
C. Countermeasure Performance Test Procedure
D. Questions
XII. Options for Characterizing Rear Visibility Countermeasures
A. Options for Display Characteristics
B. Options for Rearview Video System Camera Characteristics
C. Questions
XIII. Conclusion
XIV. Public Participation
XV. Rulemaking Analyses and Notices
Appendix A--Methodology for Assessing Backover Crash Risk by
Pedestrian Location
Appendix B--Method for On-Road Study of Drivers' Use of Rearview
Video Systems
Appendix C--Details Regarding Development of a Possible
Countermeasure Application Threshold Based on Rear Blind Zone Area
Appendix D--Results for Analysis of Correlation Between Rear Blind
Zone Area Measurement Field Size and Backing Crashes

I. Executive Summary

This advance notice of proposed rulemaking (ANPRM) initiates
rulemaking to amend Federal Motor Vehicle Safety Standard (FMVSS) No.
111, Rearview Mirrors, to improve a driver's ability to see areas to
the rear of a motor vehicle to reduce backover incidents. The agency is
issuing an ANPRM for two reasons. First, the agency is obligated,
pursuant to the Cameron Gulbransen Kids Transportation Safety Act of
2007 (the ``K.T. Safety Act'') Public Law 110-189, February 28, 2008,
122 Stat. 639, to undertake rulemaking to expand the required field of
view to enable the driver of a motor vehicle to detect areas

[[Page 9479]]

behind the vehicle to reduce death and injury resulting from backing
incidents and initiate the rulemaking in a specified time period.
Second, as there are a wide variety of means to address the problem of
backover incidents, the National Highway Traffic Safety Administration
(NHTSA) is interested in soliciting public comment on the current state
of research and the efficacy of available countermeasures.
The problem of backovers claims the lives of approximately 292
people, many of them children every year. A backover is a specifically-
defined type of incident, in which a non-occupant of a vehicle (i.e., a
pedestrian or cyclist) is struck by a vehicle moving in reverse. Unlike
most other types of crashes, many backovers occur off public roadways,
in areas such as driveways and parking lots. Furthermore, a
disproportionate number of victims of backovers are children under 5
years old and adults 70 or older. While there are several potential
reasons for this, children are particularly likely to be missed by
drivers of rear-moving vehicles because they cannot be seen due to a
``blind zone'' \3\ in the area directly to the rear of vehicle. In
addition, children are more likely to move unknowingly into a blind
zone when the driver does not suspect anyone to be there.
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\3\ We note that this is different than what many informally
call a ``blind spot,'' a term used to describe an area to the side
of the car where people may not be able to see a vehicle when
changing lanes.
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NHTSA believes that the problem of backovers warrants an
appropriate agency action. In response to a Congressional requirement
of the Safe, Accountable, Flexible, Efficient Transportation Equity
Act: A Legacy for Users (SAFETEA-LU) \4\, NHTSA has been gathering data
on backover incidents from a wide variety of sources. Based on this
research, the agency estimates that on average there are 292 fatalities
and 18,000 injuries (3,000 of which are judged to be incapacitating)
resulting from backovers every year. Of those, 228 fatalities and
17,000 injuries were attributed to backover incidents involving
passenger vehicles under 10,000 pounds. While all passenger vehicle
types (cars, sport utility vehicles, pickups, and vans) are involved in
backover fatalities and injuries, the data indicate that backover
fatality numbers show pickup trucks (72 of 288) and utility vehicles
(68 of 228) to be overrepresented when compared to all non-backing
traffic injury crashes and to their proportion to the passenger vehicle
fleet. Regardless of the type of vehicle involved, backover incidents
have garnered significant attention, due to the fact that many have
involved parents accidentally backing over their own children or
similar situations. In this notice, NHTSA describes some of the
research and information-gathering activities it has performed. This
research centers on four major topic areas.
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\4\ Safe, Accountable, Flexible, Efficient Transportation Equity
Act: A Legacy for Users (SAFETEA-LU), Public Law No. 109-59, section
1109, 119 Stat. 1114, 1168 (2005).
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The first area involves the nature of backover incidents and
backing crashes generally. NHTSA has reviewed the details of documented
backover incidents, including the locations of backover victims, the
paths the victims took to enter the path of the vehicle, and the
visibility characteristics of the vehicles involved. This notice
outlines the information we have about these crashes, whether the lack
of visibility is playing a significant role, and whether or not the
characteristics of a class or type of vehicle are a contributing
factor.
A second area of focus involves the evaluation of various
strategies for improving rear visibility. For example, one strategy
could be to ensure that the vehicles which are over represented in
terms of fatalities and injuries are improved. Such a strategy would
focus on pickup trucks or utility vehicles.\5\ Another strategy, could
seek to establish a minimum blind zone area for vehicles under 10,000
pounds. Our research indicates that a vehicle's rear blind zone area is
statistically correlated with its rate of backing crashes.\6\ Using
this correlation, it may be possible to determine which vehicles most
warrant rear visibility improvement based on the size of their rear
blind zones and the setting of a ``threshold''. Possible strategies
such as these are discussed in this notice and comments are requested.
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\5\ Fatalities and Injuries in Motor Vehicle Backing Crashes,
NHTSA Report to Congress (2008).
\6\ Partyka, S., Direct-View Rear Visibility and Backing Risk
for Light Passenger Vehicles (2008).
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The third topic involves the evaluation of various countermeasures.
NHTSA has consulted past agency research, industry and other outside
sources, and conducted new research to help determine the costs,
effectiveness, and limitations of a wide variety of countermeasures.
Four types of countermeasures are described in this notice, including
direct vision (i.e., what can be seen by a driver glancing directly out
a vehicle's windows), rear-mounted convex mirrors, rear object
detection sensors (such as ultrasonic or radar-based devices), and
rearview video (RV) systems. While research is ongoing, this notice
describes how these systems work, how well they perform in identifying
pedestrians, and how effectively drivers may use them. Where possible,
we have also included preliminary cost and benefit information. While
we examine several application scenarios (all passenger cars and all
light trucks, only light trucks, and some combinations) and discount
rates of 3 and 7 percent, the net cost per equivalent life saved for
camera systems ranged from $13.8 to $72.2 million.\7\ For sensors, it
ranged from $11.3 to $62.5 million. According to our present model,
none of the systems are cost effective compared to our comprehensive
cost estimate for a statistical life of $6.1 million.\8\
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\7\ PRIA, Executive Summary.
\8\ $6.1 million is the comprehensive value that NHTSA used for
a statistical life. Further information about this value is
available in the PRIA published with this notice.
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A fourth topic involves consideration of technical specifications
and test procedures that could be used to describe and evaluate the
performance aspects of direct view, and rear-mounted convex mirrors,
rear object detection sensors, and rearview video (RV) systems. The
agency presents preliminary information on potential technical
specifications and test procedures that we have identified and we want
to solicit information on how these specifications and procedures
should be refined for the purposes of developing repeatable compliance
tests.
Finally, NHTSA presents a series of questions in this notice. We
are requesting public input on a variety of areas, including the areas
described above, studies on the effectiveness of various indirect rear
visibility systems (i.e., devices that aid a driver in seeing areas
around a vehicle, such as mirrors or video systems) that have been
implemented in the U.S. and abroad, or technological possibilities that
can enhance the reliability of existing technologies. The agency is
also seeking information on the costs of implementation of all
available technologies to develop more robust cost and benefit
estimates.

II. Cameron Gulbransen Kids Transportation Safety Act of 2007

Subsection (b) of the Cameron Gulbransen Kids Transportation Safety
Act, directs the Secretary of Transportation to initiate rulemaking to
amend Federal Motor Vehicle Safety Standard (FMVSS) No. 111, Rearview
Mirrors, to expand the required field of view to enable the driver of a
motor vehicle to detect areas behind the motor

[[Page 9480]]

vehicle to reduce death and injury resulting from backing incidents.
The relevant provisions in subsection (b) are as follows:

(b) Rearward Visibility--Not later than 12 months after the date
of the enactment of this Act, the Secretary shall initiate a
rulemaking to revise Federal Motor Vehicle Safety Standard 111
(FMVSS 111) to expand the required field of view to enable the
driver of a motor vehicle to detect areas behind the motor vehicle
to reduce death and injury resulting from backing incidents,
particularly incidents involving small children and disabled
persons. The Secretary may prescribe different requirements for
different types of motor vehicles to expand the required field of
view to enable the driver of a motor vehicle to detect areas behind
the motor vehicle to reduce death and injury resulting from backing
incidents, particularly incidents involving small children and
disabled persons. Such standard may be met by the provision of
additional mirrors, sensors, cameras, or other technology to expand
the driver's field of view. The Secretary shall prescribe final
standards pursuant to this subsection not later than 36 months after
the date of enactment of this Act.
(c) Phase-In Period--
(1) PHASE-IN PERIOD REQUIRED--The safety standards prescribed
pursuant to subsections (a) and (b) shall establish a phase-in
period for compliance, as determined by the Secretary, and require
full compliance with the safety standards not later than 48 months
after the date on which the final rule is issued.
(2) PHASE-IN PRIORITIES--In establishing the phase-in period of
the rearward visibility safety standards required under subsection
(b), the Secretary shall consider whether to require the phase-in
according to different types of motor vehicles based on data
demonstrating the frequency by which various types of motor vehicles
have been involved in backing incidents resulting in injury or
death. If the Secretary determines that any type of motor vehicle
should be given priority, the Secretary shall issue regulations that
specify--
(A) which type or types of motor vehicles shall be phased-in
first; and
(B) the percentages by which such motor vehicles shall be
phased-in.

Congress emphasized the protection of small children and disabled
persons, and added that the revised standard may be met by the
``provision of additional mirrors, sensors, cameras, or other
technology to expand the driver's field of view.'' While NHTSA does not
interpret the Congressional language to necessarily require that all of
these technologies eventually be integrated into the final requirement,
we are examining the merits of each of them.

Applicability

With regard to the scope of vehicles covered by the mandate, the
statute refers to all motor vehicles less than 10,000 pounds (except
motorcycles and trailers). This language means that the revised
regulation would apply to passenger cars, multipurpose passenger
vehicles, buses, and trucks with a Gross Vehicle Weight Rating (GVWR)
less than 10,000 lbs.

Statutory Deadline

The Cameron Gulbransen Kids Transportation Safety Act of 2007
specified a rapid timeline for development and implementation of this
rulemaking. Specifically, the Secretary is required to publish a final
rule within 36 months of the passage of the Act (February 28, 2011).
Moreover, the agency must initiate rulemaking within 12 months of the
Act (February 28, 2009). However, it should be noted that under Section
4 of the Act,\9\ if the Secretary determines that the deadlines
applicable under this Act cannot be met, the Secretary shall establish
new deadlines, and notify the Committee on Energy and Commerce of the
House of Representatives and the Committee on Commerce, Science, and
Transportation of the Senate of the new deadlines describing the
reasons the deadlines specified under the Act could not be met.
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\9\ Cameron Gulbransen Kids Transportation Safety Act of 2007,
S.694, 110th Cong. section 4 (2007).
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III. Existing Regulatory Requirements for Rear Visibility

As of today, no country has minimum rear field of view requirements
for vehicles weighing less than 10,000 lbs. All countries do, however,
have standards for side and interior rearview mirrors, although
differences do exist in terms of mirror requirements. No country
requires rearview video systems or any other type of indirect vision
device for viewing areas directly behind the vehicle; however, Europe
does have performance requirements for systems for indirect vision, if
installed.

A. U.S.

FMVSS No. 111, Rearview Mirrors establishes requirements for the
use, field of view, and mounting of motor vehicle rearview mirrors for
rear visibility.\10\ This standard was enacted in 1976 and applies to
passenger cars, multipurpose passenger vehicles, trucks, buses, school
buses and motorcycles. The purpose of this standard is to reduce the
number of deaths and injuries that occur when the driver of a motor
vehicle does not have a clear and reasonably unobstructed view to the
rear. With respect to passenger cars, the standard requires that
manufacturers mount flat (also referred to as ``plane'' or ``unit
magnification'') mirrors both inside the vehicle and outside the
vehicle on the driver's side. The inside mirror must, except as
specified below, have a field of view at least 20 degrees wide and a
sufficient vertical angle to provide a view of a level road surface
extending to the horizon beginning not more than 200 feet (61 m) behind
the vehicle. In cases where the interior mirror does not meet the
specified field of view requirements, a plane or convex exterior mirror
must be mounted on the passenger's side of the car. While a specific
field of view is not indicated for the passenger-side rearview mirror,
the driver's side rearview mirror is required to be a plane mirror that
provides ``the driver a view of a level road surface extending to the
horizon from a line, perpendicular to a longitudinal plane tangent to
the driver's side of the vehicle at the widest point, extending 2.4 m
(7.9 ft) out from the tangent plane 10.7 m (35.1 ft) behind the
driver's eyes, with the seat in the rearmost position.''
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\10\ 49 CFR 571.111, Standard No. 111, Rearview mirrors.
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If a manufacturer uses an interior rearview mirror which meets the
field of view requirements, and wishes to install an exterior
passenger-side mirror voluntarily, it may use any type of mirror for
that purpose. In the case of light trucks, manufacturers may either
comply with the passenger car requirement or have plane or convex
outside mirrors with reflective surface area of not less than 126
square centimeters (19.5 square inches) on each side of the vehicle.
Reflectance (image brightness) criteria are also established in this
standard.
FMVSS No. 111 does not currently establish minimum rear field of
view requirements for vehicles, nor does it contain minimum
requirements for indirect vision systems, such as rearview video
systems. Because of the current absence of a federal regulation of this
aspect of performance, there is the possibility that there may be
existing State laws or regulations that regulate the vehicle's rear
field of view of passenger vehicles.\11\ However, as of this time,
NHTSA is not aware of any such State laws or regulations. However, we
request comment on existing or pending State laws or regulations in
this area, as well as the basis and effect of such regulation, if any
exist.
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\11\ See Federalism discussion below in section XV.
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B. Other Countries

ECE
In 1981, the United Nations Economic Commission for Europe (ECE)
enacted

[[Page 9481]]

Regulation 46 which details uniform provisions concerning the approval
of devices for indirect vision.\12\ ECE 46 defines devices for indirect
vision as those that observe the area adjacent to the vehicle which
cannot be observed by direct vision, including ``conventional mirrors,
camera-monitors or other devices able to present information about the
indirect field of vision to the driver.'' While ECE 46 contains
specifications for exterior rearview mirrors, it does not, directly
regulate the rear field of view. Specifications are provided to define
the required minimum size of the interior rearview mirror's surface
area, but not its field of view. This regulation applies to all power-
driven vehicles with at least four wheels that are used for the
carriage of people or goods, and vehicles with less than four wheels
that are fitted with bodywork which partly or wholly encloses the
driver.
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\12\ ECE 46-02, Uniform Provisions Concerning the Approval of:
Devices for Indirect Vision and of Motor Vehicles with Regard to the
Installation of these Devices, (August 7, 2008).
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ECE 46 requires driver and passenger ``flat'' side rearview mirrors
as found in FMVSS No. 111. ECE 46 differs from FMVSS No. 111 in that it
also permits wide-angle convex mirrors on the driver's side of the
vehicle for all classes of vehicles except for certain vehicles over
7.5 tons, for which they are required.
The ECE 46 regulation also outlines requirements for devices for
indirect vision other than mirrors for vehicles with more than eight
seating positions and those configured for refuse collection.
Specifically, it contains a general requirement that camera-monitor
devices, if present, shall perceive a visible spectrum and shall always
render this image without the need for interpretation into the visual
spectrum. The device's visual display is required to be located
approximately in the same direction as the interior rearview mirror.
The monitor is required to render a minimum contrast under various
light conditions as specified by International Organization for
Standardization (ISO) 15008:2003 \13\ and have an adjustable luminance
level. The regulation also defines detection distance, the distance
measured at ground level from the eye point to the extreme point at
which a critical object can be perceived, as an aspect of camera-
monitor device performance.
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\13\ ISO 15008:2003 Road vehicles--Ergonomic aspects of
transport information and control systems--Specifications and
compliance procedures for in-vehicle visual presentation.
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A January 2008 amendment to ECE Regulation 46 required that a
camera-monitor system must display to the driver a flat horizontal
portion of the road directly behind the vehicle from the rear bumper
outward to a distance of 2000 mm (6.6 ft). It further specified that if
an indirect vision device other than a camera-monitor is used, a test
object 50 cm (19.7 in) in height and 30 cm (11.8 in) in diameter must
be visible in the specified area. However, in a later amendment of
UNECE 46 (dated August 7, 2008) this requirement was removed and
replaced with the statement, ``Vehicles may be equipped with additional
devices for indirect vision.'' \14\ This change allows for indirect
vision systems to be installed on European vehicles without meeting any
performance requirements.
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\14\ Section 15.3.5 of ECE 46-02, Uniform Provisions Concerning
the Approval of: Devices for Indirect Vision and of Motor Vehicles
with Regard to the Installation of these Devices, (August 7, 2008).
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Canada
Canada has rearview mirror requirements that are essentially
identical to those in the U.S. All passenger cars are required to have
a driver's-side outside rearview mirror. Passenger cars are also
required to be equipped with an interior rearview mirror providing
``the driver with a field of view to the rear that is not less than 20
degrees measured horizontally rearward from the projected eye point and
extends to the horizon and includes a point on the road surface not
more than 60 m (200 feet) directly behind the vehicle.'' If the
interior rearview mirror does not meet these requirements, a side
rearview mirror must be mounted on the passenger side of the vehicle
opposite the driver's side.
Japan
Japanese regulation, Article 44, provides a performance based
requirement for rearview mirrors.\15\ For light vehicles, rearview
mirrors must be present that enable drivers to check the traffic
situation around the left-hand lane edge and behind the vehicle from
the driver's seat.\16\ The regulation requires that the driver be able
to ``visually confirm the presence of a cylindrical object 1 m high and
0.3 m in diameter (equivalent to a 6-year-old child) adjacent to the
front or the left-hand side of the vehicle (or the right-hand side in
the case of a left-hand drive vehicle), either directly or indirectly
via mirrors, screens, or similar devices.'' Article 44 does not specify
requirements for rear-mounted convex mirrors and rearview video
systems, therefore these devices are allowed, but not required under
the standard. Rear-mounted convex mirrors are commonly used as backing
aids on sport utility vehicles (SUVs) and vans in Japan; however, NHTSA
is not aware of research documenting the effectiveness of these mirrors
in mitigating backover crashes.
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\15\ Japanese Safety Regulation Article 44 and attachments 79-
81.
\16\ Vehicles manufactured for the Japanese market are right-
hand drive.
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Korea
The Korean regulation on rearview mirrors, Article 50,\17\ outlines
rearview mirror requirements for a range of vehicles. Article 50
requires a flat or convex exterior mirror mounted on the driver's side
for passenger vehicles and buses with less than 10 passengers. For
buses, cargo vehicles, and special motor vehicles, flat or convex rear-
view mirrors are required on both sides of the vehicle. Article 50 does
not address rear-mounted convex mirrors and rearview video systems,
therefore these devices are allowed, but not required under the
standard. Again, rear-mounted convex mirrors are commonly used as
backing aids on SUVs and vans in Korea; however, NHTSA is not aware of
research documenting the effectiveness of these mirrors in mitigating
backover crashes.
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\17\ Korean Safety Regulation Article 50.
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IV. Backover Safety Problem

Based on our information to date, NHTSA has found that the problem
of backovers claims the lives of hundreds of people every year. NHTSA
defines backover as a specifically-defined type of incident, in which a
non-occupant of a vehicle (i.e., a pedestrian or cyclist) is struck by
a vehicle moving in reverse. However, because many backovers occur off
public roadways, in areas such as driveways and parking lots, NHTSA's
ordinary methodologies for collecting data as to the specific numbers
and circumstances of backover incidents have not always given the
agency a complete picture of the scope and circumstances of these types
of incidents. The following sections detail NHTSA's attempts to both
quantify the number of backover incidents and determine their nature.

A. Injuries and Fatalities in Backing Incidents

In response to SAFETEA-LU Sections 2012 and 10305, NHTSA developed
the Not in Traffic Surveillance (NiTS) system to collect information
about all nontraffic crashes, including nontraffic backing crashes.
NiTS provided information on these backing crashes

[[Page 9482]]

that occurred off the traffic way and which were not included in
NHTSA's Fatality Analysis Reporting System (FARS) or the National
Automotive Sampling System--General Estimates System (NASS-GES). The
subset of backing crashes that involve a pedestrian, bicyclist, or
other person not in a vehicle, is referred to as ``backovers.'' This is
distinguished from the larger category of ``backing crashes,'' which
would include such non-backover events such as a vehicle going in
reverse and colliding with another vehicle, or a vehicle backing off an
embankment or into a stationary object. While the primary purpose of
this rulemaking is to prevent backovers, any technology that improves
rear visibility should have a positive effect on backing crashes in
general.
Based on 2002-2006 data from FARS and NASS-GES, and 2007 data from
NiTS, NHTSA estimates that 463 fatalities and 48,000 injuries a year
occur in traffic and nontraffic backing crashes.\18\ Most of these
injuries are minor injuries, but an estimated 6,000 per year are
incapacitating injuries. Overall, an estimated 65 percent (302) of the
fatalities and 62 percent (29,000) of the injuries in backing crashes
occurred in nontraffic situations.
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\18\ Fatalities and Injuries in Motor Vehicle Backing Crashes,
NHTSA Report to Congress (2008).
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With regard to injuries and fatalities related specifically to
backovers, these account for an estimated 63 percent (292) of the
fatalities and 38 percent (18,000) of the injuries in backing crashes
for all vehicles (cars, light trucks or vans, heavy trucks, and other/
multiple vehicles). Other backing crash scenarios account for an
estimated 171 fatalities (37 percent) and 30,000 injuries (62 percent)
per year. Table 1 shows the fatalities and injuries in all backing
crashes. Table 1 also demonstrates that backover victims tend to be
more seriously injured than individuals in other backing crashes (i.e.,
non-backover crash incidents). In fact, more than half (10,000 of
18,000) of the injuries in backovers are more severe than possible
(minor) injuries.

Table 1--Annual Estimated Fatalities and Injuries in All Backing Crashes for All Vehicles \19\
----------------------------------------------------------------------------------------------------------------
Injury severity Total Backovers Other backing crashes
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Estimated Sample Estimated Sample Estimated Sample
total count total count total count
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Fatalities........................ 463 1,610 292 716 171 894
Incapacitating Injury............. 6,000 304 3,000 131 3,000 173
Non-incapacitating Injury......... 12,000 813 7,000 372 5,000 441
Possible Injury................... 27,000 929 7,000 179 20,000 750
Injured Severity Unknown.......... 2,000 48 1,000 23 2,000 25
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Total Injuries................ 48,000 2,094 18,000 705 30,000 1,389
----------------------------------------------------------------------------------------------------------------
Source: FARS 2002-2006, NASS-GES 2002-2006, NiTS 2007.
Note: Estimates may not add up to totals due to independent rounding.

B. Vehicle Type Involvement in Backing Incidents
---------------------------------------------------------------------------

\19\ Id.
---------------------------------------------------------------------------

Most backover fatalities and injuries involve passenger vehicles.
As indicated in Table 2, 78 percent of the backover fatalities and 95
percent of the backover injuries involved passenger vehicles. An
estimated fifteen percent (68) of the backing crash fatalities occur in
multivehicle crashes, and an estimated thirteen percent (62) occur in
single-vehicle non-collisions such as occupants who fall out of and are
struck by their own backing vehicles. About half of the backing crash
injuries (20,000 per year) occur in multivehicle crashes involving
backing vehicles. Table 3 indicates that all major passenger vehicle
types (cars, utility vehicles, pickups, and vans) are involved in
backover fatalities and injuries. However, the data indicate that some
vehicles may have a greater risk of involvement in backing crashes than
other vehicles. Table 3 illustrates that pickup trucks and utility
vehicles are overrepresented in backover fatalities when compared to
all non-backing traffic injury crashes and to their proportion to the
passenger vehicle fleet.

Table 2--Injuries and Fatalities and Injuries by Backing Crash Type for All Vehicles
----------------------------------------------------------------------------------------------------------------
All vehicles Passenger vehicles
Backing crash scenarios ---------------------------------------------------
Fatalities Injuries Fatalities Injuries
----------------------------------------------------------------------------------------------------------------
Backovers: Striking Nonoccupant............................. 292 18,000 228 17,000
Backing: Striking Fixed Object.............................. 33 2,000 33 2,000
Backing: Noncollision....................................... 62 1,000 53 1,000
Backing: Striking/Struck by Other Vehicle................... 68 24,000 39 20,000
Backing: Other.............................................. 8 3,000 8 3,000
---------------------------------------------------
Total Backing........................................... 463 48,000 361 43,000
----------------------------------------------------------------------------------------------------------------

[[Page 9483]]

Table 3--Passenger Vehicle Backover Fatalities and Injuries by Vehicle Type
----------------------------------------------------------------------------------------------------------------
Percent
of
Estimated vehicles
Percent of Estimated percent in non- Percent
Backing vehicle type Fatalities injuries of backing of fleet
fatalities injuries traffic
injury
crashes
----------------------------------------------------------------------------------------------------------------
Car....................................... 59 26 9,000 54 62 58
Utility Vehicle........................... 68 30 3,000 20 14 16
Van....................................... 29 13 1,000 6 8 8
Pickup.................................... 72 31 3,000 18 15 17
Other Light Vehicle....................... 0 0 * 2 1 <1
Passenger Vehicles........................ 228 100 17,000 100 100 100
----------------------------------------------------------------------------------------------------------------
Source: FARS 2002-2006, NASS-GES 2002-2006, NiTS 2007.
Note: * indicates estimate less than 500, estimates may not add up to totals due to independent rounding.

C. Age Involvement in Backing Incidents

Table 4 contains the age of the backover victim for fatalities and
injuries for all backovers as well as backovers involving passenger
vehicles. Table 4 also details the proportion of the United States
(U.S.) population in each age category from the U.S. Census Bureau's
Population Estimates Program for comparison. Similar to previous
findings, backover fatalities disproportionately affect children under
5 years old and adults 70 or older. When restricted to backover
fatalities involving passenger vehicles, children under 5 account for
44 percent of the fatalities, and adults 70 and older account for 33
percent. The difference in the results between all backovers and
passenger vehicle backovers occurs because large truck backovers, which
are excluded from the passenger vehicle calculations, tend to affect
adults of working age.

Table 4--All Backover Fatalities and Injuries by Age of Victim
----------------------------------------------------------------------------------------------------------------
Estimated
Percent of Estimated percent Sample Percent of
Age of victim Fatalities injuries of count of population
fatalities injuries injuries
----------------------------------------------------------------------------------------------------------------
All Vehicles:
Under 5............................. 103 35 2,000 8 37 7
5-10................................ 13 4 * 3 33 7
10-19............................... 4 1 2,000 12 75 14
20-59............................... 69 24 9,000 48 383 55
60-69............................... 28 9 2,000 8 54 8
70+................................. 76 26 3,000 18 107 9
Unknown............................. .......... .......... * 2 16 ...........
-----------------------------------------------------------------------
Total........................... 292 100 18,000 100 705 100
Passenger Vehicles:
Under 5............................. 100 44 2,000 9 35 7
5-10................................ 10 4 1,000 3 30 7
10-19............................... 1 1 2,000 12 71 14
20-59............................... 29 13 8,000 46 319 55
60-69............................... 15 6 1,000 8 46 8
70+................................. 74 33 3,000 19 95 9
Unknown............................. .......... .......... * 2 12 ...........
-----------------------------------------------------------------------
Total........................... 228 100 17,000 100 608 100
----------------------------------------------------------------------------------------------------------------
Source: U.S. Census Bureau, Population Estimates Program, 2007 Population Estimates; FARS 2002-2006, NASS-GES
2002-2006, NiTS 2007.

The proportion of backover injuries by age group is more similar to
the proportion of the population than for backover fatalities. However,
while children under 5 years old appear to be slightly overrepresented
in backover injuries compared to the population, adults 70 and older
appear to be greatly overrepresented. One reason for the relatively
large proportion of injuries in backover crashes among older adults may
be that backovers involving younger nonoccupants may not result in an
injury while the same backover involving an older nonoccupant may
result in a fall and a broken bone.
Table 5 presents passenger vehicle backover fatalities by year of
age for victims less than 5 years old. Out of all backover fatalities
involving passenger vehicles, 26 percent (60 out of 228) of victims are
1 year of age and younger.

[[Page 9484]]

Table 5--Breakdown of Backover Fatalities and Injuries Involving
Passenger Vehicles for Victims Under Age 5 Years
------------------------------------------------------------------------
Number of
Age of victim (years) fatalities
------------------------------------------------------------------------
0.......................................................... <1
1.......................................................... 59
2.......................................................... 23
3.......................................................... 14
4.......................................................... 3
------------
Total.................................................. 100
------------------------------------------------------------------------
Note: Estimates may not add to totals due to independent rounding.
Source: U.S. Census Bureau, Population Estimates Program, 2007
Population Estimates; FARS 2002-2006, NASS-GES 2002-2006, NiTS 2007.

D. Special Crash Investigation Backover Case Summary

In addition to collecting police-reported backovers through NHTSA's
data collection infrastructure, NHTSA's efforts to understand backover
incidents have included a Special Crash Investigation (SCI) program.
The SCI program was created to examine the safety impact of rapidly
changing technologies and to provide NHTSA with early detection of
alleged or potential vehicle defects.
SCI began investigating cases related to backovers in October
2006.\20\ SCI receives notification of potential backover cases from
several different sources including media reports, police and rescue
personnel, contacts within NHTSA, reports from the general public, as
well as notifications from the NASS. As of July 1, 2008, SCI had
received a total of 52 notifications from a combination of all sources
regarding backovers.\21\ For the purpose of the SCI cases, an eligible
backover was defined as a light passenger vehicle where the back plane
strikes or passes over a person who is either positioned to the rear of
the vehicle or is approaching from the side. SCI primarily focuses on
cases involving children; however, it investigates some cases involving
adults. The majority of notifications received do not meet the criteria
for case assignment. Typically the reasons for not pursuing further
include:
---------------------------------------------------------------------------

\20\ Fatalities and Injuries in Motor Vehicle Backing Crashes,
NHTSA Report to Congress (2008).
\21\ Since SCI investigates as many relevant cases that they are
notified about as possible and not on a statistical sampling of
incidents, results are not representative of the general population.
---------------------------------------------------------------------------

[cir] The reported crash configuration is outside of the scope of
the program,
[cir] Minor incidents with no fatally or seriously injured persons,
or
[cir] Incidents where cooperation can not be established with the
involved parties.
As an example, many reported incidents are determined to be side or
frontal impacts, which exclude them from the program. NHTSA requests
that commenters submit any other existing backover incident data that
could aid in providing a clearer picture of the range of backover
accidents.
The SCI effort to examine backover crashes includes an on-site
inspection of the scene and vehicle, as well as interviews of the
involved parties when possible. When an on-site investigation is not
possible, backover cases are investigated remotely through an
examination of police-provided reports and photos as well as interviews
with the involved parties. For each backover case investigated, a case
vehicle visibility study is also conducted to determine the vehicle's
blind zones and also to determine at what distance behind the vehicle
the occupant may have become visible to the driver.
Through July 2008, NHTSA had completed special crash investigations
of 52 backover cases.\22\ The 52 backing vehicles were comprised of 17
passenger cars, 21 sport utility vehicles, and 14 pickup trucks. Only 4
of the cases (8 percent) contained vehicles equipped with a backup or
parking aid. Eighty-eight percent of the backover crashes (46 of the
52) involved children, ranging in age from less than 1 year old up to
13 years old, who were struck by vehicles. Adults were generally
excluded from the study unless they were seriously injured or killed or
if the backing vehicles were equipped with backing or parking aids. A
total of 6 cases were investigated involving struck adults. Of the 52
backover cases, exactly half (26) involved fatally injured
nonoccupants.
---------------------------------------------------------------------------

\22\ The data obtained for the SCI cases cited in this report
are based on preliminary case information. Data are subject to
change based on final investigative findings.
---------------------------------------------------------------------------

A breakdown of the victim's path of travel prior to being struck is
as follows: 24 were approaching from the right or left of the vehicle,
19 were stationary behind the vehicle, 10 were unknown, and one was
``other.'' \23\
---------------------------------------------------------------------------

\23\ Note that one or more cases examined involved multiple
victims, causing the total of the path breakdown scenarios to be 53
rather than 52.
---------------------------------------------------------------------------

E. Assessment of Backover Crash Risk by Pedestrian Location

NHTSA believes it would be helpful to know whether and to what
degree the pedestrian's location at the start of a vehicle's backing
plays a part in the likelihood of the pedestrian being struck. As such,
NHTSA used data from a recent NHTSA study of drivers' backing behavior
\24\ to estimate the relative risk of a pedestrian colliding with a
vehicle during a backing maneuver.
---------------------------------------------------------------------------

\24\ Mazzae, E. N., Barickman, F. S., Baldwin, G. H. S., and
Ranney, T. A. (2008). On-Road Study of Drivers' Use of Rearview
Video Systems (ORSDURVS). National Highway Traffic Safety
Administration, DOT 811 024.
---------------------------------------------------------------------------

A Monte Carlo simulation was used to calculate a probability-based
risk weighting for a test area centered behind the vehicle. The
probability-based risk weightings for each grid square were based on
the number of pedestrian-vehicle backing crashes predicted by the
simulation for trials for which the pedestrian was initially (i.e., at
the time that the vehicle began to back up) in the center of one square
of the grid of 1-foot squares. A total of 1,000,000 simulation trials
were run with the pedestrian initially in the center of each square.
Additional details about assumptions relating to the vehicle and
pedestrian, as well as the simulation, are presented in Appendix A.
Figure 1 summarizes the calculated relative crash risk for each
grid square. Note that the white shaded area does not have a zero
backover risk; it merely has a low (less than 15 percent of the
maximum) risk. This analysis shows that the probability of crash
decreases rapidly as the pedestrian's initial location is moved back,
further away, from the rear bumper of the vehicle. There are
substantial side lobes, giving pedestrians some risk of being hit even
though they were not initially directly behind the vehicle. The results
suggest that coverage of an area 12 feet wide by 36 feet long centered
behind the vehicle would address pedestrian locations having relative
crash risks of 0.15 and higher. To address crash risks of 0.20 and
higher, an area 7 feet wide and 33 feet long centered behind the
vehicle would need to be covered. NHTSA seeks comment on the coverage
area that is needed to establish a reasonable safety zone behind the
vehicle.
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V. Technologies for Improving Rear Visibility

Since the early 1990s, NHTSA has actively researched approaches to
mitigate backing crashes for heavy and light vehicles by assessing the
effectiveness of various backing aid technologies. In recent years,
manufacturers have added object detection sensors and video cameras to
vehicles to aid drivers in performing backing maneuvers. According to
Ward's 2008 Automotive Yearbook, backing aids utilizing sensors and/or
video cameras were installed in approximately 14 percent of model year
2007 light vehicles.\25\ While these systems are becoming increasingly
available, they have typically been marketed as parking aids to help
drivers detect and avoid obstacles in low-speed backing scenarios.
---------------------------------------------------------------------------

\25\ 2008 Ward's Automotive Yearbook.
---------------------------------------------------------------------------

To assess whether or not these systems could also be used to detect
pedestrians, the agency has, and continues to, evaluate them. The
agency has also evaluated rear-mounted convex mirrors and rearview
video systems. In the following sections, we outline the technologies
we have evaluated, research conducted by the agency and others, and
offer our preliminary observations on how they would meet the
Congressional directive to improve the rear visibility of current
vehicles.

A. Rear-Mounted Convex Mirrors

Description
Rear-mounted convex mirrors are mirrors with a curved reflective
surface thereby providing a wider field of view than plane (i.e., flat)
mirrors. These mirrors can be mounted at the upper center of the rear
window with the reflective surface pointing at the ground (commonly
referred to as backing mirrors, under mirrors, or ``look-down''
mirrors), the driver's side upper corner of the vehicle (commonly seen
on delivery vans or mail delivery trucks and called ``corner
mirrors''), or integrated into the inside face of both rearmost pillars
(called ``cross-view'' mirrors). While center or corner-mounted convex
rearview mirrors show the driver an area behind the vehicle, rear
cross-view mirror pairs are intended to aid a driver when backing into
a right-of-way by showing objects approaching on a perpendicular path
behind the vehicle.
To view the area behind a vehicle, interior rear-mounted convex
mirrors can be viewed directly by the driver, if in his direct line of
sight, or they may be looked at indirectly by viewing their reflection
in the interior or exterior rearview mirror. In the case of a rear
``look-down mirror,'' the driver can either glance rearward directly at
this mirror, or view its reflection in the interior rearview mirror.
For a rear convex corner mirror, the driver must look into the driver's
side (i.e., exterior) rearview mirror to view the reflection of the
rear convex corner mirror. In the case of rear cross-view mirrors, they
can be viewed directly by the driver or indirectly by viewing their
reflection in the interior rearview mirror.
In the U.S., rear-mounted convex mirrors are sometimes seen on
delivery trucks and vans. Rear-mounted convex mirrors are primarily
available as aftermarket products in the U.S., but are also available
as original equipment on one sport utility vehicle.\26\ In Korea and
Japan, rear-mounted convex mirrors are used on small school buses,
short delivery trucks, and some multipurpose vehicles (e.g., SUVs) to
allow drivers to view areas behind a vehicle.
---------------------------------------------------------------------------

\26\ Rear cross-view mirrors have been available on the Toyota
4Runner base model vehicles since MY 2003.
---------------------------------------------------------------------------

While rear convex cross-view mirrors are available as aftermarket
products that mount to the inside of the rear window for all passenger
car body types, this is not the case for look down mirrors. Rear convex
look-down or corner convex mirrors need to have a rear window that is
vertically aligned with the rear of the vehicle (such as a station
wagon, SUV or van) in order to have a clear view of the area behind the
vehicle.
Research
NHTSA has conducted research on rear-mounted convex mirrors for use
on medium straight trucks and to a limited extent, passenger vehicles
(i.e., cars, trucks, vans, SUVs). The research and how its results may
be related to the improvement of rear visibility are discussed below.
Passenger Vehicle Research
In response to Section 10304 of the Safe, Accountable, Flexible,
Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-
LU),\27\ NHTSA conducted a study to evaluate methods to reduce the
incidence of injury, death, and property damage caused by backing
collisions of passenger vehicles.\28\ The examination of two convex
mirror systems revealed that pedestrians and objects were not visible
in some areas directly behind the vehicle (this area could be described
as the area bounded by the vertical planes formed by the sides of the
vehicle, and extending rearward). The research also found that the
convexity of the mirrors caused significant image distortion, and
reflected objects were difficult to discern. It is unknown if this
issue can be addressed in future designs. For the tested designs,
concentrated glances were necessary to identify the nature of rear
obstacles; it is not known if a driver making quick glances prior to
initiating a backing maneuver would allocate sufficient time to allow
recognition of an obstacle or pedestrian shown in the mirror.
---------------------------------------------------------------------------

\27\ SAFETEA-LU, Sec. 1109, 119 Stat. 1168.
\28\ Mazzae, E.N. and Garrott, W.R., Experimental Evaluation of
the Performance of Available Backover Prevention Technologies, NHTSA
Technical Report No. DOT HS 810 634, September 2006.
---------------------------------------------------------------------------

Current Mirror Research
NHTSA is currently evaluating the image quality (distortion and
minification) and field of view of rear-mounted convex mirrors. The
mirror types being examined include an aftermarket rear convex look-
down mirror, aftermarket rear corner convex mirror, aftermarket rear
convex cross-view mirrors designed for SUVs and passenger cars (e.g.,
sedans, coupes), and original equipment rear convex cross-view mirrors
on a 2003 Toyota 4Runner.
Figure 2 below illustrates the types of measurements that NHTSA
plans to collect to evaluate the image quality and field of view for
rear convex mirrors. As illustrated in the Figure, using a test device
that simulates a 1-year-old child, the rear convex look-down mirror
shows an area directly behind a vehicle (a 2007 Honda Odyssey minivan)
but beyond 15 feet from the bumper, the image could not be discerned.
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Using the same 1-year-old child-sized test device, Figure 3
illustrates the measured field of view for an exemplar rear convex
cross-view mirror system. The area behind the vehicle cannot be seen,
rather, only the area that extends outward from both rear corners of
the vehicle.
[GRAPHIC] [TIFF OMITTED] TP04MR09.002

NHTSA previously evaluated the quality of images displayed by a
rear corner convex mirror mounted on a 1996 Grumman-Olsen step van with
a 12-foot long box.\29\ Using those data, an analysis was performed in
which linear extrapolation and two-dimensional interpolation \30\ were
applied to estimate at which of four locations behind the vehicle a 1-
year-old child dummy (i.e., anthropomorphic test device, or ATD) could
be visible to a driver using a rear corner convex mirror. The four
locations assessed are labeled A through D in Figure 4.
---------------------------------------------------------------------------

\29\ Mazzae, E.N., and Garrott, W.R., Experimental Evaluation of
the Performance of Available Backover Prevention Technologies for
Medium Straight Trucks, NHTSA Technical Report No. DOT HS 810 865,
November 2007.
\30\ Measured minutes of arc subtended by the test object were
first linearly extrapolated to estimate the effects of differences
in the distance from the driver eyepoint to the side rearview mirror
and the distance from the side rearview mirror to the rear corner
convex mirror. Two-dimensional linear interpolation was then used to
correct for reducing the vehicle width from the 7.0 feet for the
step van to the 6.0 feet more typical of light passenger vehicle and
for estimating minutes of arc subtended at the four locations, A
through D. Note that estimates based upon multiple multi-linear
extrapolation/interpolation were made because they could be done
quickly using data that NHTSA had previously collected.

---------------------------------------------------------------------------

[[Page 9489]]

[GRAPHIC] [TIFF OMITTED] TP04MR09.003

The reflected image of the 1-year-old dummy becomes less minified
and is easier for the driver to discern as the location of the dummy
moves either forward towards the rear bumper of the vehicle or
laterally towards the driver's side of the vehicle. Therefore, for a
vehicle for which the dummy is visible at Point A, the dummy is
expected to be visible anywhere across the entire width of the vehicle
for distances up to at least 10 feet from the vehicle's rear bumper.
Estimated visibility of the 1-year-old dummy for each of the four
locations (identified in Figure 4) for 9 vehicles is shown in Table 6.

Table 6--Visibility of a 1-Year-Old Child Dummy Using a Corner Rear Cross-View Mirror
--------------------------------------------------------------------------------------------------------------------------------------------------------
Year Make Model Can see Point A? Can see Point B? Can see Point C? Can see Point D?
--------------------------------------------------------------------------------------------------------------------------------------------------------
2008............................ Chevrolet......... Express........... No................ No................ No................ Yes.
2003............................ Volvo............. XC90.............. No................ No................ Yes............... Yes.
2005............................ Nissan............ Armada............ No................ No................ No................ Yes.
2007............................ Saturn............ Vue............... No................ No................ Yes............... Yes.
2007............................ Jeep.............. Commander......... No................ No................ Yes............... Yes.
2008............................ Toyota............ Highlander........ No................ No................ Yes............... Yes.
2007............................ Ford.............. Edge.............. No................ No................ Yes............... Yes.
2005............................ Chevrolet......... Uplander.......... No................ No................ No................ Yes.
2003............................ Toyota............ 4Runner........... No................ No................ Yes............... Yes.
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 9490]]

As the table indicates, it is not expected that a driver could see
the 1-year-old dummy when the dummy is located directly behind the
passenger's side of the vehicle at a distance of 6 or 10 feet back from
the vehicle's rear bumper. The quality of the reflected image is better
on the vehicle's centerline, with the dummy expected to be visible for
six out of nine vehicles when it is located 10 feet back from the rear
bumper and visually discernable to the driver for all nine vehicles
when it is only 6 feet aft of the rear bumper.
This mirror research is scheduled to be completed in 2009 and will
be summarized in a published NHTSA report thereafter. Along with
comments received to this notice, NHTSA hopes to use this research
information in the development of a proposal.
Observations
Some advantages of rear-mounted convex mirrors include that when
compared to video cameras and object detection sensors, they are
relatively inexpensive (e.g., less than $40 retail as an aftermarket
product) and have the potential to last the life of the vehicle. They
also provide a wider field of view than that provided by plane mirrors.
However, they also possess inherent disadvantages. In general, convex
mirrors compress (i.e., minify) and distort the image of reflected
objects in their field of view. This image distortion and image
minification make objects and pedestrians appear very narrow and
difficult for the driver to discern and identify. These aspects of
image quality worsen as the length of the vehicle increases.
Rear cross-view mirrors are positioned to show an area to the side
and rear of the vehicle but they do not provide a good view of the area
directly behind the vehicle (the area bounded by two imaginary planes
tangent to the sides of the vehicle. As such, a pedestrian or object in
this area could be invisible to the driver. They can however, help
drivers see objects approaching the rear of the vehicle along a
perpendicular path. NHTSA is aware that single rear convex look-down
mirrors are commonly found on SUVs and vans in Korea and Japan.
However, we are unaware of any publicly available studies that have
been conducted to assess the effectiveness of these mirrors in
improving rear visibility. We seek comment on the availability of any
such studies.

B. Rearview Video Systems

Description
A growing number of vehicles in the U.S. are equipped with rearview
video systems. These systems can permit a driver to see much of the
area behind the vehicle via a video display showing the image from a
video camera mounted on the rear of the vehicle. The images may be
presented to the driver using an existing screen in the vehicle, such
as a navigation system or multifunction display screen, or by adding a
display incorporated into the dashboard or interior rearview mirror.
Costs for these rearview video systems are estimated at
approximately $58-$88 for vehicles equipped with a navigation system or
other type of multi-function visual display, to $158-$189 for vehicles
requiring a dashboard-mounted display screen, or $173-$203 for vehicles
with an RV display integrated into the interior rearview mirror.\31\
---------------------------------------------------------------------------

\31\ PRIA, section VI.
---------------------------------------------------------------------------

Research
Recent research on rearview video systems conducted by NHTSA and
our observations about the research are presented below.
NHTSA Testing in Support of SAFETEA-LU
In response to Section 10304 of SAFETEA-LU, NHTSA examined three
rearview video systems (RV): One in combination with original equipment
rear parking sensors, one aftermarket system combining both RV and
parking sensor technologies, and one original equipment RV system.\32\
This examination of RV systems included assessment of their field of
view and their potential to provide drivers with information about
obstacles behind the vehicle.
---------------------------------------------------------------------------

\32\ Mazzae, E.N. and Garrott, W.R., Experimental Evaluation of
the Performance of Available Backover Prevention Technologies, NHTSA
Technical Report No. DOT HS 810 634, September 2006.
---------------------------------------------------------------------------

Through this study, the agency made the following observations. The
rearview video systems examined provided a clear image of the area
behind the vehicle in daylight and indoor lighting conditions. RV
systems displayed images of pedestrians or obstacles behind the vehicle
to a substantial range of 23 feet or more, except for an area within 8-
12 inches of the rear bumper at ground level. Beyond the rear bumper,
the rearview video systems also displayed areas wider than 50 feet.
The location and angle at which the rearview video camera is
mounted on the back of the vehicle affects the size of the field of
view provided by the system. The longitudinal range of the images
displayed by the two original equipment RV systems tested differed
significantly. One rearview video system's camera presented an image
having a limited vertical angle, resulting in a substantially shorter
longitudinal range along the centerline of the vehicle (ending at
approximately 23 feet from the rear bumper at ground level). For a 3-
year-old child dummy centered 2 feet behind the vehicle, the shorter
visible range exhibited by this particular RV system caused the top of
the dummy's head to be out of view.
Observations
We found that RV systems can display areas on the ground almost
directly adjacent to the bumper of the vehicle. Furthermore, RV systems
offer the possibility of a wide field of view, with some systems able
to show 180 degrees behind the vehicle.
However, during the short course of testing, NHTSA also noted some
operational issues with video camera performance in certain weather
conditions, such as rain and snow. For example, rain drops and the
buildup of ice on the video camera lens can significantly reduce the
quality of the view provided by the RV system. Also, in evaluating
these technologies we have not had the opportunity to assess the long-
term performance and reliability of RV systems, as well as the effects
of harsh weather conditions on their long-term operation.

C. Sensor-Based Rear Object Detection Systems

Description
Sensor-based object detection systems use electronic sensors that
transmit a signal which, if an obstacle is present in a sensor's
detection field, bounces the signal back to the sensor producing a
positive ``detection'' of the obstacle. These sensors detect objects in
the vicinity of a vehicle at varying ranges depending on the
technology. To date, commercially-available object detection systems
have been based on short-range ultrasonic technology or longer range
radar technology, although advanced infrared sensors are under
development as well.
Sensor-based object detection systems have been available for over
15 years as aftermarket products and for a lesser period as original
equipment. Original equipment systems have been marketed as a
convenience feature or ``parking aid'' for which the vehicle owner's
manual can contain language denoting

[[Page 9491]]

sensor performance limitations with respect to detecting children or
small moving objects. Aftermarket systems, however, are frequently
marketed as safety devices for warning drivers of the presence of small
children behind the vehicle.
NHTSA has investigated the cost of sensor-based rear object
detection systems. Currently, we estimate the cost of a backing system
based on ultrasonic technology to be $51-$89 and the cost of a system
based on radar technology to be approximately $92.\33\
---------------------------------------------------------------------------

\33\ PRIA, section VI.
---------------------------------------------------------------------------

Research
NHTSA Research in Support of SAFETEA-LU
NHTSA examined eight sensor-based original equipment and
aftermarket rear parking systems in response to Section 10304 of the
SAFETEA-LU mandate.\34\ NHTSA conducted testing to measure the object
detection performance of short range sensor-based systems. Measurements
included static field of view (i.e., both the vehicle and test objects
were static), static field of view repeatability, and dynamic detection
range for different laterally moving test objects. The agency assessed
the system's ability to detect a 74-inch-tall adult male walking in
various directions to the rear of the vehicle. Detection performance
was also evaluated in a series of static and dynamic tests with 1-year-
old and 3-year-old children.
---------------------------------------------------------------------------

\34\ Mazzae, E.N. and Garrott, W.R., Experimental Evaluation of
the Performance of Available Backover Prevention Technologies, NHTSA
Technical Report No. DOT HS 810 634, September 2006.
---------------------------------------------------------------------------

Sensor-based systems tested were generally inconsistent and
unreliable in detecting pedestrians, particularly children, located
behind the vehicle. Testing showed that, in most cases, pedestrian size
affected detection performance, as adults elicited better detection
response than 1 or 3-year-old children. Specifically, each system could
generally detect a moving adult pedestrian (or other objects) behind a
stationary vehicle; however, each system exhibited some difficulty in
detecting moving children. The sensor-based systems tested were found
to operate reliably (i.e., without malfunction), with the exception of
one aftermarket ultrasonic system that malfunctioned after only a few
weeks, rendering it unavailable for use in remaining tests.
While examining the consistency of system detection performance,
the agency observed that each sensor-based system exhibited some degree
of variability in its detection performance and patterns. Specifically,
detection inconsistencies were generally noticed at the periphery of
the detection zones and typically for no more than 1 foot in magnitude.
On average, these sensor-based systems had detection zones which
generally covered an area directly behind the vehicle. The system with
the longest detection range could detect a 3-year-old child up to 11
feet from the rear bumper (along a 3-5 ft wide strip of area along the
vehicle's centerline). The majority of systems were unable to detect
test objects less than 28 inches in height.
The response times of sensor-based systems were also evaluated in
this study. In order for sensor-based backover avoidance systems to
assist in preventing collisions, warnings must be generated by the
system in a timely manner and the driver must perceive the warning
within sufficient time to respond appropriately to avoid a crash. With
regards to system response times, ISO 17386:2004,\35\ ``Manoeuvring
Aids for Low Speed Operation (MALSO)--Performance requirements and test
procedures'', outlines performance requirements for sensor-based object
detection systems. This standard recommends a maximum system response
time of 0.35 seconds. NHTSA's tests showed that the response times for
the eight tested sensor systems varied from 0.18 to 1 second, and only
three of them met the ISO response time limit. For the systems that did
not meet the recommended 0.35-second limit, it is unlikely (assuming
typical backing speeds \36\ and driver reaction times) that warnings
would be provided to a driver in sufficient time to allow the driver to
bring the vehicle to a stop and avoid a possible collision with an
obstacle or moving child.
---------------------------------------------------------------------------

\35\ ISO 17386:2004 Transport information and control systems--
Manoeuvring Aids for Low Speed Operation (MALSO)--Performance
requirements and test procedures.
\36\ Note that average backing speed was found to be 2.26 mph in
NHTSA's ``On-Road Study of Drivers' Use of Rearview Video Systems
(ORSDURVS).'' Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and
Ranney, T.A. (2008). National Highway Traffic Safety Administration,
DOT 811 024, page 34.
---------------------------------------------------------------------------

NHTSA Experimental Research: Performance of Sensor-Based Rear Object
Detection Systems
NHTSA's 2008 study of drivers' use of rearview video systems \37\
involved an observation of drivers of vehicles equipped with an
ultrasonic-based rear parking sensor system in addition to an RV
system. In a staged experimental trial in which an unexpected obstacle
was presented to test participants while backing out of a garage, the
rear parking sensor system on the particular vehicle involved in this
study detected the obstacle and provided a warning indication of the
presence of the obstacle behind the vehicle in 38 percent (5 out of 13)
of the event trials for participants with vehicles equipped with the
combination system. These data describing the performance of a sensor-
based rear parking aid as used by average drivers reflect similar
detection performance deficiencies as have been observed in NHTSA's
laboratory testing of the detection performance of sensor-based object
detection systems.^{38 39}
---------------------------------------------------------------------------

\37\ Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and Ranney,
T.A. (2008). On-Road Study of Drivers' Use of Rearview Video Systems
(ORSDURVS). National Highway Traffic Safety Administration, DOT 811
024.
\38\ Mazzae, E.N. and Garrott, W.R., Experimental Evaluation of
the Performance of Available Backover Prevention Technologies, NHTSA
Technical Report No. DOT HS 810 634, September 2006.
\39\ Mazzae, E.N. and Garrott, W.R., Experimental Evaluation of
the Performance of Available Backover Prevention Technologies for
Medium Straight Trucks, NHTSA Technical Report No. DOT HS 810 865,
November 2007.
---------------------------------------------------------------------------

Paine, Macbeth & Henderson Proximity Sensor Research
Paine, Macbeth & Henderson tested the performance of proximity
sensor backing aids.\40\ They reported that proximity sensors tested
exhibited limited ability to detect objects for vehicles traveling at 5
km/h (3.1 mph) or more. According to their conclusions, proximity
sensors were prone to produce ``nuisance alarms'' in some driving
situations and were deemed an unviable option to reduce backing
incidents. While the authors suggested that a more effective system to
mitigate backing incidents may be to incorporate sensors and wide-angle
video camera technology, no data were provided to support this
statement.
---------------------------------------------------------------------------

\40\ Paine, M., Macbeth, A., and Henderson, M. (2003). The
Danger to Young Pedestrians from Reversing Motor Vehicles. 18th
International Technical Conference on the Enhanced Safety of
Vehicles. Paper Number 466.
---------------------------------------------------------------------------

GM Experimental Research on Sensor-Based Systems for the Reduction of
Backing Incidents
GM outlined the functional capabilities of their ultrasonic rear
park assist system. The system was designed to detect larger poles and
parking barriers greater than 7.5 cm in diameter with a length of 1.0
meter or more. It was not designed to detect objects less than 25 cm in
height. In addition, the system was not designed to detect obstacles
directly below the bumper or under the vehicle. GM notes that smaller
or thinner objects or pedestrians

[[Page 9492]]

may not be detected by this system, and indicates this fact explicitly
in the system's instructional materials.^{41 42}
---------------------------------------------------------------------------

\41\ Instructional materials include the following warning: ``If
children, someone on a bicycle, or pets are behind your vehicle,
(ultrasonic rear park assist) won't tell you they are there. You
could strike them and they could be injured or killed.''
\42\ Green, C. and Deering, R. (2006). Driver Performance
Research Regarding Systems for Use While Backing. Society of
Automotive Engineers, Paper No. 2006-01-1982.
---------------------------------------------------------------------------

Observations
The development of sensor-based systems for use as parking aids has
been in progress for at least 15 years. Ultrasonic sensors inherently
have detection performance that varies as a function of the degree of
sonic reflectivity of the obstacle surface. For example, objects with a
smooth surface such as plastic or metal reflect well, whereas objects
with a textured surface, such as clothing, may not reflect as well.
Radar sensors, which are able to detect the water in a human's body,
are better able to detect pedestrians, but demonstrate inconsistent
detection performance, especially with regard to small children.
NHTSA is aware that the performance of current sensor-based systems
can be influenced by the algorithms that are used for detection. As
stated previously, these systems are implemented as parking aids rather
than safety systems and thus this may have attributed to the observed
performance. While it is possible to modify the detection algorithms of
sensor-based object detection systems to allow for better detection of
children, one result of such a modification could result in other less
favorable aspects of system performance, such as increased false
alarms. From a driver confidence standpoint, an increase in false
alarms could have the effect of decreasing the system's overall
effectiveness as a driver's desire to use the system decreases.

D. Multi-Technology (Sensor + Video Camera) Systems

Description
In the context of this document, multi-technology backing aid
systems are those systems that utilize both video and sensor-based
technologies. Prior to MY 2007, these technologies functioned
independently if both were present on a vehicle. Recently, truly
integrated systems that use data from rear object detection sensors to
present obstacle warnings that are superimposed on the RV display image
have become commercially available. Whether integrated or not, vehicles
equipped with both rearview video and sensor technologies have the
ability to detect obstacles (via a rear parking sensor system) and
alert a driver (by directing their attention to the rearview video
system display) to the presence of the obstacle.
Research
As previously mentioned in Part C of this section, NHTSA's work in
response to Section 10304 of the SAFETEA-LU mandate included the
measurement of the object detection performance of short range sensor-
based systems. One of the systems examined was the integrated rearview
video and ultrasonic-based rear parking aid system of a 2007 Cadillac
Escalade. This system used object detection information from an
ultrasonic rear parking aid to present obstacle warnings to the driver
through warning symbology superimposed on the RV display image.
Specifically, a warning triangle symbol was shown on the RV display
image in the approximate location of the obstacle. While the
performance of the ultrasonic-based rear parking aid system showed the
same issues as other tested systems using that sensor technology, the
presentation of integrated warnings may be useful in directing a
driver's attention to the image of a rear obstacle presented on the
rearview video display. However, in order to assess the effectiveness
of this or any other integrated system in mitigating backover
incidents, research with drivers using the system is needed.
Observations
Testing of the vehicle examined showed that the integrated rear
parking aid and rearview video aspects of the backing aid system
performed, from a sensor point of view, the same as would these two
technologies if tested separately. The performance of the backing aid
technologies present on this vehicle may not represent the performance
of all such systems commercially available today. With improved
technology integration that may utilize image processing to confirm the
presence of rear obstacles, performance enhancements may be possible.
The agency seeks comment on whether any recent studies have been
performed with other integrated multi-technology backing aid systems.

E. Future Technologies

Description
NHTSA is aware of two additional sensor technologies being
developed that could be used to improve a vehicle's rear visibility;
infrared-based object detection systems and video-based object
recognition systems. As with other sensor systems, infrared-based
systems emit a signal, which if an object is within its detection
range, will bounce back and be detected by a receiver. Rear object
detection via video camera uses real-time image processing capability
to identify obstacles behind the vehicle and alert the driver of their
presence.
Research
Ongoing NHTSA Backing Crash Countermeasure Research
In addition to the previously mentioned rear-mounted convex mirror
research, NHTSA is currently engaged in cooperative research with GM on
Advanced Collision Avoidance Technology relating to backing incidents.
The ACAT backing systems project is assessing the ability of more
advanced technologies to mitigate backing crashes, and refining a tool
to assess the potential safety benefit of these technologies. The focus
of the ACAT Backing Crash Countermeasure Program is to characterize
backing crashes in the U.S. and investigate a set of integrated
countermeasures to mitigate them at appropriate points along the crash
timeline (prior to entering the vehicle and continuing throughout the
backing sequence). The objective of this research is to estimate
potential safety benefits or harm reduction that these countermeasures
might provide. A Safety Impact Methodology (SIM), consisting of a
software-based simulation model together with a set of objective tests
for evaluating backing crash countermeasures, will be developed to
estimate the harm reduction potential of specific countermeasures.
Included in the SIM's methods for estimating potential safety benefits
will be a consideration of assessing and modeling unintentional
potential disbenefits that might arise from a countermeasure.
Observations
While these technology applications may eventually prove viable,
because of their early stages of development it is not possible at this
time to assess their ability to effectively expand the visible area
behind a vehicle. Similarly, the completion of NHTSA's advanced
technology research effort is not expected until calendar year 2011 and
thus will not occur prior to the Congressional deadline. The agency
seeks comments on the timeframe for the commercial availability of
these technologies, and on any other

[[Page 9493]]

advanced technology developments not identified here.

F. Summary and Questions Regarding Technologies for Improving Rear
Visibility

Given the mandate from Congress to improve the rear visibility of
vehicles, NHTSA's preliminary assessment of the known research to date
seems to indicate that RV systems have greater potential to improve
vehicles' rear visibility than sensor-based rear object detection
systems and rear-mounted convex mirrors. However, we believe it is
premature to limit manufacturers' design options at this time. To this
end, we put forth the following questions and solicit comments on our
assessments of these technologies, and any information on the
feasibility of alternative approaches or systems.
(1) While the objective to ``expand the required field of view to
enable the driver of a motor vehicle to detect areas behind'' the
vehicle implies enhancement of what a driver can visually see behind a
vehicle, the language of the K.T. Safety Act also mentions that the
``standard may be met by the provision of additional mirrors, sensors,
cameras, or other technology.'' NHTSA seeks comment regarding the
ability of object detection sensor technology to improve visibility and
comply with the requirements of the Act.
(2) What specific customer feedback have OEMs received regarding
vehicles equipped with rear parking sensor systems? Have any component
reliability or maintenance issues arisen? Is sensor performance
affected by any aspect of ambient weather conditions?
(3) What specific customer feedback have OEMs received regarding
vehicles equipped with rearview video systems? Have any rearview video
system component reliability or maintenance issues arisen?
(4) What are the performance and usability characteristics of
rearview video systems and rear-mounted convex mirrors in low light
(e.g., nighttime) conditions?
(5) Is there data available regarding consumers' and vehicle
manufacturers' research regarding backing speed limitation, haptic
feedback to the driver, or use of automatic braking?
(6) What types of rear visibility countermeasures are anticipated
to be implemented in the vehicle fleet through the 2012 timeframe?
(7) Can rear-mounted convex mirrors be installed on light vehicles
other than SUVs and vans? What is the rationale for U.S. manufacturers'
choosing to install rear parking sensors and video cameras, rather than
rear-mounted convex mirrors as are commonly installed on SUVs and
minivans in Korea and Japan? NHTSA is particularly interested in any
information on the effectiveness of rear-mounted convex mirrors in
Korea and Japan.
(8) NHTSA seeks any available research data documenting the
effectiveness of rear convex cross-view mirrors in specifically
addressing backover crashes.
(9) NHTSA seeks comment and data on whether it is possible to
provide an expanded field of view behind the vehicle using only rear-
mounted convex mirrors.
(10) NHTSA is aware of research conducted by GM that suggests that
drivers respond more appropriately to visual image-based confirmation
of object presence than to non-visual image based visual or auditory
warnings. Is there additional research on this topic?
(11) NHTSA requests input and data on whether the provision of
graphical image-based displays (e.g., such as a simplified animation
depicting rear obstacles), rather than true-color, photographic visual
displays would elicit a similarly favorable crash avoidance response
from the driver.
(12) To date, rearview video systems examined by NHTSA have
displayed to the driver a rear-looking perspective of the area behind
the vehicle. Recently introduced systems which provide the driver with
a near 360-degree view of the area around the entire vehicle do so
using a ``birds-eye'' perspective using images from four cameras around
the vehicle. During backing, it appears that, by default, this birds-
eye view image is presented simultaneously along with the traditional
rear-facing camera image. NHTSA requests data or input on whether this
presentation method is likely to elicit a response from the driver that
is at least as favorable as that attained using traditional, rear-view
image perspective, or whether this presentation is more confusing for
drivers.

VI. Drivers' Use and the Associated Effectiveness of Available
Technologies To Mitigate Backovers

In order to establish effectiveness estimates for different systems
which may be utilized to mitigate backover crashes, the agency has
conducted research on vehicles equipped with such systems, including
those utilizing ultrasonic and radar sensors and rearview video
cameras. As with any passive technology, NHTSA believes that it is
reasonable to assume that in order for the technology to assist in
preventing backing crashes, the driver must use the technology (e.g.,
look at the video display, if present), perceive the indication that a
pedestrian or object is present, and respond quickly, and with
sufficient force applied to the brake pedal, to bring the vehicle to a
stop. While we have previously discussed the performance of the
technologies, this section will outline what the agency knows about
driver use and the resulting effectiveness of technologies that could
be used to mitigate backover crashes.
NHTSA has not conducted system effectiveness research with drivers
for all of the four system types discussed in this notice. However,
that relevant research NHTSA and industry have conducted is summarized
here.

A. Rear-Mounted Convex Mirrors

NHTSA has not conducted research focused on examining driver's use
of mirrors to aid in the performance of backing maneuvers. However,
NHTSA's study of drivers' use of rearview video systems during staged
and naturalistic backing maneuvers did produce data regarding drivers'
use of the side and interior rearview mirrors as well as direct glance
behavior.\43\ This behavior suggests that drivers would use the
mirrors. Table 7 shows that the mean percentage of total glance time
during a backing maneuver in which drivers glanced at the driver-side
mirror, passenger-side mirror, and interior rearview mirror.
Independent of the presence of a backing aid, drivers spent over 25
percent of the time during a backing maneuver glancing rearward over
their right shoulder.
---------------------------------------------------------------------------

\43\ Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and Ranney,
T.A. (2008). On-Road Study of Drivers' Use of Rearview Video Systems
(ORSDURVS). National Highway Traffic Safety Administration, DOT 811
024.

[[Page 9494]]

Table 7--Mean Percentage of Total Glance Time to Mirror Locations for a
Backing Maneuver With Staged Obstacle Avoidance Event \44\
------------------------------------------------------------------------
Mean
percentage
of total
Glance location glance time
during a
backing
maneuver
------------------------------------------------------------------------
Driver-side Mirror/Driver-side Window \45\................. 15
Interior Rearview Mirror................................... 5
Passenger-side Mirror/Passenger-side Window \46\........... 15
------------------------------------------------------------------------

NHTSA is currently engaged in research to examine the performance
of these mirrors in displaying images of rear obstacles. While NHTSA
has not yet conducted driving research with these mirrors we are
planning to conduct research to examine drivers' behavior and ability
to avoid crashes with rear-mounted convex mirrors in 2009. Upon
completion, this mirror research will be summarized in a published
NHTSA report. Along with comments received to this notice, NHTSA hopes
to use this research information in the development of a proposal.
---------------------------------------------------------------------------

\44\ Id.
\45\ Note that due to the close proximity of the mirror and
window on each side of the vehicle, the driver-side mirror and
driver-side window glance locations were impossible to distinguish
from each other.
\46\ Note that due to the close proximity of the mirror and
window on each side of the vehicle, the passenger-side mirror and
passenger-side window glance locations were impossible to
distinguish from each other.
---------------------------------------------------------------------------

B. Rearview Video Systems

NHTSA has conducted and we are aware of some work conducted by GM
that examined drivers' use of rearview video based backing aids and
their ability to use them to mitigate crashes. Below is a brief summary
of this research.
NHTSA Experimental Research: On-Road Study of Drivers' Use of Rearview
Video Systems
NHTSA conducted experimental research aimed to determine whether
drivers look at the RV display during backing. While hardware
performance testing has shown the rearview video systems can provide to
the driver an image of any obstacles behind the vehicle in the RV
system's field of view, the driver must take the initiative to look at
the display throughout the backing maneuver in order for the RV system
to provide any benefit. The goal of this study was to further our
understanding of the degree to which drivers may actively use RV
systems while backing and whether the provision of such visual
information will translate into decreased backing and backover
incidents.
This study also provided information useful in estimating the
effectiveness of RV and supplemental sensors, in aiding drivers to
avoid a backing crash. For example, the number of times per backing
maneuver that a driver looked at the RV screen was tabulated. A driver
that looks at the screen more often is more likely to notice when an
obstacle appears. A look at the beginning of a backing maneuver is less
likely to result in a driver's detection of an obstacle than would
frequent checking of the screen throughout the maneuver.
Drivers' use of rearview video systems was observed during staged
and naturalistic backing maneuvers to determine whether drivers look at
the RV display during backing and whether use of the system affects
backing behavior.\47\ Thirty-seven test participants, aged 25 to 60
years, were comprised of twelve drivers of RV-equipped vehicles,
thirteen drivers of vehicles equipped with an RV system and a rear
parking sensor system, and twelve drivers of vehicles with no backing
aid system. All three system conditions were presented using original
equipment configurations of the 2007 Honda Odyssey minivan. All
participants had driven and owned a 2007 Honda Odyssey minivan as their
primary vehicle for at least six months. Participants were not aware
that the focus of the study was on their behavior and performance
during backing maneuvers.
---------------------------------------------------------------------------

\47\ Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and Ranney,
T.A. (2008). On-Road Study of Drivers' Use of Rearview Video Systems
(ORSDURVS). National Highway Traffic Safety Administration, DOT 811
024.
---------------------------------------------------------------------------

Participants drove their own vehicles for a period of four weeks in
their normal daily activities while backing maneuvers were recorded. At
the end of four weeks, participants returned to the research lab to
have the recording equipment removed. At the lab, the participants took
a test drive in which an unexpected 36-inch-tall obstacle consisting of
a two-dimensional photograph of a child appeared behind the vehicle
during a final backing maneuver. Additional details of the test method
are provided in Appendix B of this notice.
The results of the naturalistic driving and unexpected obstacle
scenario are provided below.
Results for Naturalistic Driving
A total of 6,145 naturalistic backing maneuvers were
recorded in the study, none of which resulted in a significant
collision; however, some collisions (i.e., with trash receptacles and
other parked vehicles) occurred during routine backing.
In the real-world backing situations, drivers equipped
with RV systems spent 8 to 12 percent of the time looking at the RV
display during backing maneuvers.
On average, drivers made 2.17 glances per backing maneuver
with the RV-only system, and 1.65 glances per maneuver with the RV and
sensor system.
Overall, drivers looked at least once at the RV display on
approximately 65 percent of backing events, and looked more than once
at the RV display on approximately 40 percent of backing events.
Results for Unexpected Obstacle Maneuver
Drivers with an RV system made 13 to 14 percent of glances
at the RV video display during the initial phase of backing in the
staged maneuvers, independent of system presence.
Drivers spent over 25 percent of backing time looking over
their right shoulder in the staged backing maneuvers.
Only participants who looked at the RV display more than
once during the maneuver avoided a crash during the staged crash-
imminent obstacle event.
Results indicated that the RV system was associated with a
statistically significant (28 percent) reduction in crashes with the
unexpected obstacle as compared to participants without an RV system.
All participants in the ``no system'' condition crashed, since the
staged obstacle event scenario was designed such that drivers without
an RV system could not see the obstacle.
Results of this study indicate that drivers looked at the RV
display in approximately 14 percent of glances in baseline and obstacle
events and 10 percent of glances in naturalistic backing maneuvers. The
agency recognized that the timing and frequency of drivers' glances at
the RV display has a noticeable impact on the likelihood of rear
obstacle detection. However, making single or multiple glances at the
RV display at the start of the maneuver does not ensure that the path
behind the vehicle will remain clear for the entire backing maneuver.
Overall, this study estimates that video-based backing systems
would

[[Page 9495]]

mitigate approximately 28 to 42 percent of backover crashes \48\.
---------------------------------------------------------------------------

\48\ Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and Ranney,
T.A. (2008). On-Road Study of Drivers' Use of Rearview Video Systems
(ORSDURVS). National Highway Traffic Safety Administration, DOT 811
024.
---------------------------------------------------------------------------

GM Experimental Research on Driver Performance Using Video-Based
Backing Aid Systems
GM conducted research to investigate ways to assist drivers in
recognizing people or objects behind their vehicle while performing
backing maneuvers.\49\ One study compared parking behaviors for rear
camera and ultrasonic rear parking assist systems together, separately,
and under traditional parking conditions (i.e., neither system). An
obstacle was placed unexpectedly behind a driver's vehicle prior to the
start of a backing maneuver to assess the driver's performance in
obstacle detection and avoidance.\50\ Twenty-four participants struck
the obstacle, while five participants avoided the obstacle. Of those
participants who avoided the obstacle, three saw the obstacle while
looking at the RV display (two in the RV system condition, one in the
ultrasonic rear park assist and RV system condition), one saw the
obstacle in their mirror (ultrasonic rear park assist and RV system
condition), and one participant noticed the obstacle out of the back
window (RV system condition). These results indicated that participants
with an RV system were less likely to be involved in a backing
incident.
---------------------------------------------------------------------------

\49\ Green, C. and Deering, R. (2006). Driver Performance
Research Regarding Systems for Use While Backing. Society of
Automotive Engineers, Paper No. 2006-01-1982.
\50\ McLaughlin, S.B., Hankey, J.M., Green, C.A., and Kiefer,
R.J. (2003). Driver Performance Evaluation of Two Rear Parking Aids.
Proceedings of the 2003 Enhanced Safety Vehicle Conference.
---------------------------------------------------------------------------

GM also sponsored a second research study to evaluate driver
performance with rear camera systems.\51\ In this study, each
participant parked their vehicle using a rear camera and ultrasonic
system more than 30 times, including practice trials. During one
scenario, participants, unaware that an experimenter placed an obstacle
behind the vehicle, were asked to perform a backing maneuver to engage
the ultrasonic rear park assist and the rear camera system. In some
cases, a flashing symbol was employed in the approximate location of
the rear obstacle as presented on the video display screen. While there
were no statistically significant effects of either the symbol or the
location of the obstacle, 65 percent of participants avoided the
obstacle. Greater experience with the camera system and an increased
number of trials presented that involved a ruse may have attributed to
a higher object avoidance rate in this study than compared to the first
study.
---------------------------------------------------------------------------

\51\ Green, C. and Deering, R. (2006). Driver Performance
Research Regarding Systems for Use While Backing. Society of
Automotive Engineers, Paper No. 2006-01-1982.
---------------------------------------------------------------------------

Overall, GM's research on rearview video systems suggested that RV
systems may provide limited benefit in some backing scenarios.\52\
---------------------------------------------------------------------------

\52\ Green, C. and Deering, R. (2006). Driver Performance
Research Regarding Systems for Use While Backing. Society of
Automotive Engineers, Paper No. 2006-01-1982.
---------------------------------------------------------------------------

C. Sensor-Based Rear Object Detection Systems

NHTSA and GM have both conducted research on drivers' use of
sensor-based backing aids and their ability to use them to mitigate
crashes. Below is a brief summary of this research.
NHTSA Experimental Research: Driver Performance With Rearview Video and
Sensor-Based Rear Object Detection Systems
NHTSA's study of drivers' use of rearview video systems (discussed
in detail earlier in this document) also involved an observation of
drivers of vehicles equipped with both an RV system and an ultrasonic-
based rear parking sensor system. The rear parking sensor system tested
detected the obstacle and provided a warning indication of the presence
of a rear obstacle to the driver in 38 percent (5 out of 13) of the
event trials for participants with vehicles equipped with the
combination system. Four of these 5 participants crashed into the
obstacle.
The test vehicle involved in the study had a control that allowed
the driver to disable the parking sensor system. During the course of
this study, half of the participants whose vehicles were equipped with
a rear parking sensor system either stated or were observed to have
turned the system off at least some of the time. Four participants made
unsolicited comments to members of the research staff about turning off
the rear parking sensor system on their vehicle.\53\ One of the four
participants reported that he just did not use it. The three other
participants stated that they frequently turned the rear parking sensor
system off when driving through a restaurant drive-through lane due to
nuisance alarms (i.e., audible notifications of the presence of
vehicles that the driver is already aware of). A sixth participant did
not comment on not using the system, but was observed having the rear
parking sensor system on their vehicle switched off during their
initial meeting visit. This tendency for some drivers to turn the rear
parking sensor system off causes NHTSA to be concerned about the
potential for this technology to be effective in mitigating backover
incidents.
---------------------------------------------------------------------------

\53\ Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and Ranney,
T.A. (2008). On-Road Study of Drivers' Use of Rearview Video Systems
(ORSDURVS). National Highway Traffic Safety Administration, DOT 811
024.
---------------------------------------------------------------------------

GM Experimental Research on Driver Performance Using Sensor-Based
Backing Aid Systems
GM sponsored a study on the effectiveness of auditory backing
warnings provided by a rear object detection system.\54\ The study
found that only 13 percent of drivers avoided hitting an unexpected
obstacle, and over 87 percent of the drivers collided with the obstacle
following the warning. Sixty-eight percent of drivers provided with the
warning demonstrated precautionary behaviors in response to the
warning, such as covering the brake with their foot, tapping the brake,
or braking completely. While 44 percent of participants braked, these
braking levels were generally insufficient to avoid a collision.
Although data provides some evidence that warnings influenced driver
behavior, warnings were unreliable in terms of their ability to induce
drivers to immediately brake to a complete stop.
---------------------------------------------------------------------------

\54\ Green, C. and Deering, R. (2006). Driver Performance
Research Regarding Systems for Use While Backing. Society of
Automotive Engineers, Paper No. 2006-01-1982.
---------------------------------------------------------------------------

This study further suggests that knowledge and experience with a
backing warning system may not significantly improve immediate driver
response to a backing warning. While specific training on the operation
of the system was provided to eight drivers, only one avoided the
obstacle. In each case, drivers reported that they did not expect to
encounter an obstacle in their backing path. Many drivers also reported
that they searched for an obstacle following the warning, but ``didn't
see anything'' and continued their backing maneuver. These perceptions
suggest that drivers' expectations are important when seeking to
influence driver behavior.
NHTSA Experimental Research: Driver Performance With Sensor-Based Rear
Object Detection Systems
NHTSA is currently engaged in research to assess drivers' ability
to avoid backing crashes in a vehicle equipped with only a sensor-based
rear object detection system. This work is scheduled to be completed in
2009 and

[[Page 9496]]

will be summarized in a published NHTSA report thereafter. Along with
comments received to this notice, NHTSA hopes to use this research
information in the development of a proposal.

D. Multi-Technology (Sensor + Camera) Systems

NHTSA has not conducted research examining drivers' use of any
integrated, multi-technology systems designed to aid drivers in
performing backing maneuvers. However, NHTSA's study of drivers' use of
rearview video systems (discussed in detail earlier in this document)
involved an observation of drivers of vehicles equipped with both an RV
system and an ultrasonic-based rear parking sensor system that
functioned independently. Data from this study indicated that equipping
a vehicle with a rear object detection system and an RV system that are
not integrated resulted in lesser backing crash avoidance effectiveness
than attainable with RV alone. Although statistically not significant
due to the relatively small number of test participants, more
participants with vehicles equipped with both an RV and a rear parking
sensor system (85 percent) crashed into an obstacle than did those (58
percent) driving vehicles equipped with only an RV system. However, the
fact that the rear parking sensor system only detected the obstacle in
38 percent of test trials may help explain the result if the drivers
relied on the sensor system first. NHTSA's research on the performance
of currently available sensor-based systems in detecting rear obstacles
has shown their performance to be inconsistent, particularly in the
detection of small children. It is possible that those performance
deficits for sensor-based rear object detection systems could have a
negative impact on the overall effectiveness of RV systems,
particularly if drivers rely on the sensor system's auditory alerts to
cue them to look at the RV display.
During our study, drivers of the vehicles with RV and sensors
looked at the RV system visual display less frequently than did drivers
of the same vehicle equipped with only the RV system. NHTSA seeks
comment on whether there is research that would indicate why this would
occur or if others have found a similar trend.

E. Summary

Table 8 presents a summary of the estimated effectiveness
information for systems that may aid in the mitigation of backover
incidents that NHTSA has collected to date. Estimates for system
performance in detecting rear obstacles and overall effectiveness based
on driver use are listed separately. System performance for rearview
video systems was assumed to be 100 percent, since these systems have
the capability to show any object within their field of view. System
performance for sensor-based systems is based on object detection rates
seen in the obstacle avoidance event presented in the study of drivers'
use of rearview video systems.\55\ Overall effectiveness values for
rearview video systems alone and combined with a rear parking sensor
system are based on results of NHTSA's study of drivers' use of
rearview video systems. The value for rear parking sensor systems is
calculated based on a combination of the 39 percent object detection
rate from the study of drivers' use of rearview video systems and
additional data that NHTSA has collected. We note that GM's study of
drivers' use of backing warning systems found that only 13 percent of
drivers were able to avoid a crash with a rear obstacle in a staged
scenario using a rear parking sensor system.\56\
---------------------------------------------------------------------------

\55\ Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and Ranney,
T.A. (2008). On-Road Study of Drivers' Use of Rearview Video Systems
(ORSDURVS). National Highway Traffic Safety Administration, DOT 811
024.
\56\ General Motors (2006). Driver Performance Research
Regarding Systems for Use While Backing. Society of Automotive
Engineers, Paper No. 2006-01-1982.

Table 8--Estimated System Performance and Overall Effectiveness
------------------------------------------------------------------------
System performance Percent overall
in object effectiveness
Countermeasure detection-- (technology +
percent detections driver)
------------------------------------------------------------------------
Rear-Mounted Convex Mirrors..... (Research (Research
underway). underway).
Rearview Video.................. 100............... 42 \57\.
Rearview Video + Sensors........ 100............... 15 \58\.
Sensors......................... 39 \59\........... 17.66 \60\
(estimate).
------------------------------------------------------------------------

F. Questions

(1) NHTSA has not conducted research to estimate a drivers' ability
to avoid crashes with a backing crash countermeasure system based only
on sensor technology. We request any available data documenting the
effectiveness of backing crash countermeasure systems based only on
sensor technology in aiding drivers in mitigating backing crashes.
(2) NHTSA has not conducted research to estimate drivers' ability
to avoid crashes with a backing crash countermeasure system based on
multiple, integrated technologies (e.g., rear parking sensors and
rearview video functions in one integrated system). We request any
available objective data documenting the effectiveness of multi-
technology backing crash countermeasure systems in mitigating backing
crashes. We also request comment on what types of technology
combinations industry may consider feasible for use in improving rear
visibility.
---------------------------------------------------------------------------

\57\ Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and Ranney,
T.A. (2008). On-Road Study of Drivers' Use of Rearview Video Systems
(ORSDURVS). National Highway Traffic Safety Administration, DOT 811
024.
\58\ Id.
\59\ Id.
\60\ PRIA, section V.
---------------------------------------------------------------------------

(3) NHTSA requests any available data documenting the image quality
of rear-mounted convex mirrors and their effectiveness in aiding
drivers in preventing backing crashes.
(4) NHTSA requests any available additional objective research data
documenting the effectiveness of sensor-based, rearview video, mirror,
or combination systems that may aid in mitigating backover incidents.
(5) NHTSA requests information regarding mounting limitations for
rear-mounted convex mirrors.

VII. Rear Visibility of Current Vehicles

The degree of direct rear visibility (i.e., what a driver can
directly see with or without the aid of non-required mirrors or other
devices) in a particular vehicle depends on a number of factors,
including the driver's size and various aspects of the vehicle's
design, such as the width of a vehicle's structural pillars (i.e., B
and C pillars) and the size of its window openings. Rear seat head
restraints can also affect direct rear

[[Page 9497]]

visibility.\61\ Additionally, due to their geometries and the position
of a driver's eyes with respect to the bottom of the rear window (or
top edge of a pickup truck's tailgate), vehicles with greater overall
height and length are likely to have larger rear blind zone areas than
shorter vehicles.
---------------------------------------------------------------------------

\61\ Note that 49 CFR Sec. 571.111 Standard No. 111, Rearview
mirrors, Section 5.1.1 states that ``The line of sight may be
partially obscured by seated occupants or by head restraints.''
---------------------------------------------------------------------------

To assess a vehicle's rear visibility and how it varies from
vehicle to vehicle, in 2007,\62\ NHTSA measured the rear visibility
characteristics of 44 recent-model light vehicles.\63\ NHTSA's
measurements involved assessment of the visibility of a visual target
over an area stretching 35 feet to either side of the vehicle's
centerline, 90 feet back from the vehicle's rear bumper, and 20 feet
forward of the rear bumper. Rear visibility metrics were calculated
using a subset of this area measuring 60 feet wide by 50 feet long
(3000 square feet). The agency selected a 29.4-inch-tall visual target
representing the approximate height of a 1-year-old child and the
youngest walking potential backover victims. Rear visibility was
measured for both a 50th percentile adult male driver (69.1 inches
tall) and a 5th percentile adult female driver (59.8 inches tall). The
areas over which the visual target was visually discernible using
direct glances (i.e., looking out vehicle windows) and indirect glances
(i.e., looking into side or interior rearview mirrors) were determined.
---------------------------------------------------------------------------

\62\ Mazzae, E.N., Garrott, W.R. (2008). Light Vehicle Rear
Visibility Assessment. National Highway Traffic Safety
Administration, DOT 810 909.
\63\ Measured vehicles included the ten top-selling passenger
cars and light trucks for calendar year 2006.
---------------------------------------------------------------------------

While NHTSA measured the area indirectly visible to the driver in
the side and interior rearview mirrors, we focused our assessment on
direct rear visibility in order to assess the degree to which the
vehicle's structure affects what a driver can see out the vehicle's
windows. This permitted an assessment of how rear visibility is
affected by a vehicle's structure and allowed for better vehicle
comparison since this metric varied more than would rear visibility
measured using both direct vision and indirect vision devices together.
In other words, considering both direct and indirect rear visibility
together would allow less room for distinguishing between the qualities
of rear visibility amongst vehicles. Examples of the measured direct
fields of view for four common vehicles types are shown in Figures 5-8.
BILLING CODE 4910-59-P

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BILLING CODE 4910-59-C
Through this study, NHTSA estimated that rear blind zone areas \64\
for individual vehicles ranged from approximately 100 to 1,440 square
feet over the 3,000 square-foot measurement area. When summarized by
vehicle category and curb weight (as a surrogate indicator for vehicle
size), as illustrated in Figure 9, the data shows that average direct-
view rear blind zone areas varied within these groups. The greatest
range of direct-view rear blind zone area size was seen for the 4,000-
5,000 lb SUV group. Figure 10 illustrates that SUVs (as a whole) were
associated with the largest average direct-view rear blind zone area as
well as the largest range of values for the four body types examined.
Overall, LTVs (vans, pickups, and SUVs) as a vehicle class were
observed to have larger rear blind zone areas than passenger cars, as
indicated in Figure 10.
---------------------------------------------------------------------------

\64\ ``Rear blind zone area'' is defined here to mean the area
in square feet within a 50-foot wide by 60-foot long area and at
ground level over which a 29.4-inch-tall object is visible using
direct vision.

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[GRAPHIC] [TIFF OMITTED] TP04MR09.009

For all 44 vehicles, NHTSA also measured the distance behind the
vehicle at which the visual target could first be seen, i.e., the
direct-view rear longitudinal sight distance. Average direct-view rear
longitudinal sight distances were determined by mathematically
averaging eight longitudinal sight distance measurements taken in 1-
foot increments across the rear of each vehicle. As illustrated in
Figure 11, LTVs generally had longer rear longitudinal sight distances
than passenger cars. Exceptions to this trend included a few small
pickup trucks for which average direct-view rear sight distance values
were in the vicinity of those measured for smaller passenger cars, as
shown in Figure 12. Average direct-view rear sight distance values

[[Page 9503]]

were longest for a full-size van, SUVs and pickup trucks with a curb
weight of 4,000 lbs or greater.
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[[Page 9504]]

Overall, our direct-view rear visibility measurements indicated
that LTVs measured in this study exhibited worse rear visibility when
compared with passenger cars, but there was overlap amongst all vehicle
categories.

VIII. Relationship Between Rear Visibility and Backing/Backover Crashes

Using the direct-view rear blind zone area and longitudinal sight
distance measurements \65\ discussed in the prior section, NHTSA
investigated whether a statistical relationship could be identified
between these metrics and all backing crashes, as well as backover
crashes (i.e., the subset of backing crashes involving a pedestrian or
bicyclist being struck by a backing vehicle).\66\ NHTSA assessed the
relationship between real world backing/backover crashes and rear
visibility based on three metrics: average rear longitudinal sight
distance, direct-view rear visibility measurements for a 50 feet long
by 60 feet wide \67\ test area, and direct-view rear visibility for a
50 feet long by 20 feet wide \68\ test area.
---------------------------------------------------------------------------

\65\ Mazzae, E.N., Garrott, W.R. (2008). Light Vehicle Rear
Visibility Assessment. National Highway Traffic Safety
Administration, DOT 810 909.
\66\ Partyka, S., Direct-View Rear Visibility and Backing Risk
for Light Passenger Vehicles (2008).
\67\ This area was chosen because it was the largest available
measurement area for the facility in which these measurements were
conducted.
\68\ The 50 feet long by 20 feet wide test area was examined to
assess how much of the area behind the vehicle was critical to
consider for rear visibility in relation to the prevention of
backover incidents.
---------------------------------------------------------------------------

Backing risk was estimated from police-reported crashes in the
State Data System.\69\ To calculate risk, backing rates were derived
for 21 vehicle groups with vehicles that had at least 25 backing
crashes to account for statistical variability. Backing rate data were
provided by the following states for the specified calendar years:
---------------------------------------------------------------------------

\69\ The states provide annual files of their police-reported
data under voluntary agreements with NHTSA. These are collected by
the National Center for Statistics and Analysis, Office of Data
Acquisition. The data are available for agency use. Public release
of any of the files requires written approval from the individual
state.

Alabama (2000-2003)
Florida (2000-2005)
Georgia (2000-2005)
Illinois (2000-2005)
Kansas (2001-2006)
Kentucky (2000-2005)
Maryland (2000-2005)
Michigan (2004-2006)
Missouri (2000-2005)
Nebraska (2000-2004)
New Mexico (2001-2006)
New York (2000)
North Carolina (2000-2005)
Pennsylvania (2000-2001, 2003-2005)
Utah (2000-2004)
Washington (2002-2005)
Wisconsin (2000-2005)
Wyoming (2000-2005)
Simple correlation analysis \70\ revealed an association between
direct-view rear blind zone area and backing crash risk. Specifically,
larger blind zone areas tended to be associated with a greater risk of
being involved in a backing crash. A statistically significant
relationship \71\ between backing crash risk and direct-view rear blind
zone area was discovered for both test areas, suggesting that this
metric is a sensitive predictor of backing crash risk. However, in this
analysis, the association between average rear longitudinal sight
distance and backing risk was found to be weaker and not statistically
significant due to the relatively small number of backover incidents,
suggesting that this metric is not a sensitive predictor of backing
crash risk.\72\
---------------------------------------------------------------------------

\70\ A simple correlation measures the strength of the
statistical relationship between two variables. For example, one can
graph two variables (such as the real-world risk of being involved
in a backing crash as a function of laboratory measures of rear
visibility) as a scatter plot. A simple correlation analysis
measures how closely the plot resembles a line. If the plot suggests
a line, then we might conclude that the laboratory measures are
useful in predicting real-world involvements. However, it is
difficult to use this approach if one suspects that there are
complicating (confounding) factors that affect the simple comparison
between two variables.
\71\ r=0.51, p=0.02.
\72\ r=0.26.
---------------------------------------------------------------------------

Logistic analysis \73\ for the risk of a backover incident produced
results that approached statistical significance for the rear blind
zone area metrics, with a similar trend and magnitude as those for all
backing crashes. Vehicles with the largest blind zone areas had 2-3
times the risk of a backover incident than those vehicles with the
smallest blind zone areas.\74\ Conversely, estimated results for the
risk of backover using rear longitudinal sight distance were not
statistically significant.
---------------------------------------------------------------------------

\73\ A logistic analysis allows us to account for complicating
factors (such as systematic differences in how vehicles are used and
by whom) by including them in a statistical model. This model
predicts the risk of a crash being a backing crash as a function the
laboratory measures of rear visibility after removing (controlling
for) the effects of measurable complicating factors.
\74\ Partyka, S., Direct-View Rear Visibility and Backing Risk
for Light Passenger Vehicles (2008).
---------------------------------------------------------------------------

IX. Options for Mitigating Backover Incidents

Using rear blind zone area as a metric, NHTSA's research seems to
indicate that there is a range of performance amongst vehicles and that
LTVs on average had worse rear visibility than passenger cars. NHTSA
also found a statistically significant correlation between rear blind
zone area and backing crashes. Finally, our crash data appear to
indicate that LTVs are overrepresented in backing and backover crashes.
Based on these findings, NHTSA has identified potential approaches to
improve rear visibility and to address the backing and backover crash
risks for passenger vehicles.

A. Approaches for Improving Vehicles' Rear Visibility

One approach would be to eliminate all rear blind zones by
requiring that all vehicles have a rear blind zone size of 0 sq. ft.
(i.e., no rear blind zone). Such a requirement would be met by a
visibility enhancement countermeasure that allowed the driver to see or
otherwise determine that a pedestrian is in a specified zone behind the
vehicle. This strategy would improve rear visibility for all vehicles.
Alternatively, NHTSA could specify that all LTVs as a vehicle class
have no rear blind zone since our crash data indicated that this
vehicle category seems to be overrepresented in backing and backover
crashes. This alternative would target the class of vehicles which are
disproportionately responsible for the largest portion of backover
fatalities.
Another approach would be to establish a maximum rear blind zone
area limit (based on crash rate) that all vehicles, or LTVs as a
vehicle class, would have to meet.\75\ The threshold would be applied
to all vehicles, such that any vehicle not meeting the minimum rear
visibility threshold would be required to be equipped with a rear
visibility countermeasure. Because styling engineers would have a
target threshold giving them an idea of minimum ``acceptable'' rear
visibility, such an approach would allow manufacturers the flexibility
to consider and improve those attributes of a vehicle that contribute
to rear visibility since they would have the option of not having to
provide a rear visibility enhancement countermeasure. Depending on how
high or low the threshold was set, for example, the agency could focus
countermeasure application on vehicles with the largest rear blind zone
areas and those vehicles

[[Page 9505]]

that are most involved in backing and backover crashes.
---------------------------------------------------------------------------

\75\ Additional details on how a rear blind zone area based
threshold might be developed are in Appendix D.
---------------------------------------------------------------------------

Using these approaches, NHTSA offers our preliminary information
regarding the benefits and costs of various scenarios.

B. Cost Benefit Scenarios

For the relevant technologies, we have generated estimates using
two different types of video cameras available in the market today and
two different types of object detection sensors. For rearview video
systems, some manufacturers are using cameras with a 130-degree field
of view while others are using ones with a 180-degree field of view.
These are noted as ``130 [deg] Camera'' and ``180 [deg] Camera,''
respectively. Note that these angular values are camera specifications
and indicate the angle of view with respect to the center of the camera
lens and not the center of the rear of the vehicle. Due to styling
issues, cameras on some vehicle models may be mounted off-center and,
as a result, their fields of view may not be symmetrical with respect
to the center of the vehicle's rear bumper. The sensor technologies
included in the estimates are ultrasonic and radar. It should be noted
that given our lack of information regarding the effectiveness of
mirrors, we could not generate a cost benefit scenario using this
technology.
Using various scenarios, NHTSA has developed preliminary estimates
of the costs and benefits for improving rear visibility assuming 16.6
million (8.5 million LTVs and 8.1 million passenger cars) total
vehicles.\76\ One scenario involves the application of a rear
visibility countermeasure to all vehicles and a second assumes that a
countermeasure is applied to all LTVs and no passenger vehicles. Given
that a rear visibility threshold has not yet been established and that
NHTSA has not measured all vehicle models sold in the U.S. to determine
their rear blind zone areas, two additional, hypothetical scenarios
were considered. One scenario assumes that a rear visibility
countermeasure would be required for all LTVs and any passenger cars
that do not comply with the rear visibility threshold (hypothetically
assumed to encompass 25 percent of vehicles).\77\ Another scenario
assumes that a rear visibility countermeasure would be required for any
light vehicle that does not comply with the rear visibility threshold
(hypothetically assumed to encompass 75 percent of LTVs and 25 percent
of passenger cars).\78\ Table 9 presents the overall range of costs and
benefits across these four scenarios.
---------------------------------------------------------------------------

\76\ This sales figure represents 2007 vehicle sales. For the
subsequent NPRM, updated sales figures will be used.
\77\ To illustrate this approach, this example scenario assumes
that 25 percent of passenger cars will not comply with the rear
visibility threshold.
\78\ To illustrate this approach, this example scenario assumes
that 75 percent of LTVs and 25 percent of passenger cars will not
comply with the rear visibility threshold.

Table 9--Preliminary Benefits and Costs Estimates--Across Four Countermeasure Application Scenarios \79\
----------------------------------------------------------------------------------------------------------------
Net cost (does
not consider
Countermeasure technology options vehicles already Cost per life Total fatalities Total injuries
equipped with RV) saved (in $M) avoided avoided
(in $M)
----------------------------------------------------------------------------------------------------------------
RV with 130 [deg] Camera and $1,153-$2,577 $16.17-$57.27 26-69 1,279-5,189
Interior Mirror Display............
RV with 130 [deg] Camera and In-Dash 981-2,294 15.69-56.41 26-69 1,279-5,189
Display............................
RV with 180 [deg] Camera and 1,325-3,005 13.76-50.99 31-82 1,689-6,141
Interior Mirror Display............
RV with 180 [deg] Camera and In-Dash 1,234-2,811 14.61-52.76 31-82 1,689-6,141
Display............................
Ultrasonic Rear Object Detection 277-766 11.25-33.84 5-24 399-1,793
System.............................
Radar Rear Object Detection System.. 571-1,397 21.02-49.84 6-26 479-1,976
---------------------------------------------------------------------------
Rear-mounted Convex Mirrors......... (Research in progress)
----------------------------------------------------------------------------------------------------------------

Additional details regarding these calculations can be found in the
preliminary regulatory impact analysis document, ``Rear Visibility
Technologies: FMVSS No. 111.'' NHTSA will continue to gather
information on price and vehicle equipment trends for use in refining
these estimates of costs and benefits for improving rear visibility.
---------------------------------------------------------------------------

\79\ Cost calculations presented in Table 9 assume a 3 percent
discount rate. Values also consider ranges of effectiveness for the
technologies listed. Additional details regarding these calculations
can be found in the PRIA.
---------------------------------------------------------------------------

C. Questions

NHTSA requests comments on benefits and costs for rear visibility
enhancement countermeasures and the possibility of developing a rear
blind zone area based minimum acceptable rear visibility threshold.
Specific questions are as follows:
(1) NHTSA seeks comment on the areas behind a vehicle that may be
most important to consider when improving rear visibility. Furthermore,
while the distribution of visible area behind the vehicle was not
considered in the blind zone area metrics (e.g., rear blind zone area)
discussed in this document, it may be helpful to specify some specific
areas behind the vehicle that must be visible.
(2) NHTSA invites comment as to how an actual threshold based on
vehicles' rear blind zone area could be defined.
(3) For vehicles whose rear visibility does not meet a required
minimum threshold and thus require a countermeasure, OEMs may decide to
further alter the styling of the rear of the vehicle to the detriment
of direct rear visibility (e.g., making the rear window a tiny,
circular porthole). Based on the fact that NHTSA's research \80\ showed
that drivers of RV-equipped vehicles glanced at least one time at the
RV display in only 65 percent of backing maneuvers, maintaining good
direct rear visibility may be important for the other 35 percent of
cases in which the RV system is not used. Therefore, NHTSA is
considering specifying a minimum portion of a vehicle's rear visibility
that must be provided via direct vision (i.e., without the use of
mirrors or other indirect vision device). NHTSA seeks comments on this
approach, such as input regarding how a minimum threshold should be
specified, and how much of a vehicle's rear area should be visible via
direct vision?
---------------------------------------------------------------------------

\80\ Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and Ranney,
T.A. (2008). On-Road Study of Drivers' Use of Rearview Video Systems
(ORSDURVS). National Highway Traffic Safety Administration, DOT 811
024.

---------------------------------------------------------------------------

[[Page 9506]]

(4) NHTSA requests information regarding anticipated costs for rear
visibility enhancement countermeasures.
(5) Given the increasing popularity of LCD panel televisions and
likely resulting price decline, what decline in price can be
anticipated for LCD displays used with rearview video systems? Will
similar price reduction trends be seen for video cameras for rearview
video system application?
(6) NHTSA requests information on the estimated price of rear
visibility enhancement countermeasures at higher sales volumes, as well
as the basis for such estimates.
(7) NHTSA requests any available data on rearview video system
maintenance frequency rates and replacement costs. How often are
rearview video cameras damaged in the field?
(8) NHTSA requests comments on which types of possible rear
visibility enhancement countermeasure technologies may be considered
for use on which types of vehicles. This information is important for
estimating the costs of countermeasure implementation in the fleet.
(9) NHTSA requests information regarding available studies or data
indicating the effectiveness of dashboard display-based rearview video
systems and rearview mirror based rearview video systems. What are the
key areas that will impact the real-world effectiveness of these
systems as they become more common in the fleet?
(10) NHTSA requests objective data on the use, effectiveness, and
cost of rear-mounted convex mirrors.

X. Options for Measuring a Vehicle's Rear Visibility

If a maximum rear blind zone area limit threshold is used to
establish the need for a vehicle to be equipped with a countermeasure,
its rear visibility characteristics would need to be measured and that
vehicle's direct-view rear visibility and rear blind zone areas would
need to be calculated. As such, if the agency chooses to establish a
threshold value for minimum performance, a test procedure would need to
be developed. In this section, the agency identifies those test
procedures it has identified that could be used for this purpose. The
advantages and disadvantages of the different identified methods are
also discussed.

A. Rear Visibility Measurement Procedures

Society of Automotive Engineers
The Society of Automotive Engineers (SAE) \81\ has created a
recommended practice for determining the areas around a vehicle that a
driver can see through direct vision (i.e., without the use of mirrors
or another indirect vision device). This procedure uses computer-based
simulations to describe rear visibility for a particular vehicle. Using
standard driver eye points and a three-dimensional computer model of
the vehicle, the simulation allows the rotation of sight lines
originating from the eye points to determine the areas that the driver
should be able to see outside the vehicle.\82\ This approach to
determine a vehicle's visibility characteristics is theoretical and has
not been assessed for reproducibility and repeatability against actual
vehicles.
---------------------------------------------------------------------------

\81\ SAE J1050, Describing and Measuring the Driver's Field of
View; Revised 2003-01.
\82\ Note: NHTSA has not evaluated the engineering drawings or
three-dimensional computer models of manufactured vehicles, on which
this method appears to rely.
---------------------------------------------------------------------------

Paine, Macbeth & Henderson
In 2003, Paine, Macbeth & Henderson described a method to
approximate a driver's sight line using an H-point machine and laser
pointing device. Using the data, a ``visibility index'' was calculated
to highlight the researchers' belief that vehicle design plays a major
role in the rear visibility of vehicles.
This study, sponsored by the Insurance Australia Group, was
designed to be easily repeatable and standardized to enable accurate
comparisons between vehicles.\83\ The laser device was mounted to the
side of the H-point machine's head fixture in the approximate vicinity
of where a driver's head would be located. A dimensioned grid was
positioned behind the test vehicle and a test target consisting of a
cylinder 600 mm (24 in.) tall and 200 mm (7.87 in.) in diameter was
used. Additionally, the driver's seat was placed in its lowest and
furthest back position and adjusted to ensure that the rear of the H-
point device was placed at a 25 degree angle.
---------------------------------------------------------------------------

\83\ Paine, M., Macbeth, A., and Henderson, M. (2003). The
Danger to Young Pedestrians from Reversing Motor Vehicles. 18th
International Technical Conference on the Enhanced Safety of
Vehicles. Paper Number 466.
---------------------------------------------------------------------------

Data from this test procedure were used to calculate vehicle
ratings by considering several factors including the total visible area
behind the vehicle; the visible distance across the rear of the
vehicle; and the presence of backing aids such as proximity sensors and
rearview camera systems. Consequently, the authors identified several
vehicle design aspects that affect rear visibility, including a high
bootlid (referred to as the ``trunk lid'' in the US); rear-mounted
spare tires; rear head restraints; center high-mounted brake lights;
rear mounted wipers; and rear spoilers.
NHTSA believes the rear visibility assessment method outlined by
these researchers has merit. However, further refinement may be
desirable. For instance, a more accurate eye point for location of the
laser beam would better simulate what a 50th percentile male would be
able to see. The agency is undertaking research to examine the use of
laser-based methods of measuring a vehicle's rear visibility
characteristics.
Consumer Reports Linear Rear Blind Spot Measurement Method
Consumer Reports evaluates vehicles for rear visibility and
publishes the findings as part of their new vehicle reviews. In their
August 2006 report, they examined vehicles to determine the closest
distance at which a 28-inch object (approximating the height of a child
less than 1 year old) could be detected behind a vehicle.\84\ During
the evaluation, drivers \85\ were seated in the vehicle and asked to
detect an object while it was moved outward from the rear of the
vehicle along its centerline. The distance from the rear bumper at
which the driver could detect the object was measured, and then these
sight distances were published as consumer information.
---------------------------------------------------------------------------

\84\ Consumer Reports (August, 2006). Blind-zone measurements.
http://www.consumerreports.org/cro/cars/safety-recalls/mind-that-blind-spot-1005/blindspot-measurements/index.htm.
\85\ The heights of the subject drivers were 68 inches
(approximate height for a 50th percentile adult male) and 61 inches
(approximate height for a 5th percentile small female).
---------------------------------------------------------------------------

Consumer Reports' data describe a rear sight distance as measured
at the centerline of the vehicle, which may not accurately describe
rear visibility across the entire width of the rear of the vehicle and
therefore not fully address the risk of a backing crash. In addition,
the use of human drivers, particularly a single driver of a particular
height, to estimate rear visibility for a vehicle is likely to produce
results that are subject to variability stemming from individual
differences. While this information may be helpful to consumers, for
the purposes of establishing a Federal regulation on rear visibility,
NHTSA would be required to follow an approach that has demonstrated
objectivity and repeatability.

[[Page 9507]]

NHTSA's Human-Based Rear Visibility Measurements
In 2007, NHTSA measured the rear visibility characteristics of 44
vehicles using human drivers to report the actual area around a vehicle
where they could detect a 29.4-inch-tall test object.\86\ During the
test procedure, the visual target was moved behind the vehicle over a
grid of 1-foot squares spanning 110 feet longitudinally (including 90
feet behind the vehicle's rear bumper) and 70 feet laterally (i.e., 35
feet to either side of the vehicle's centerline). Points on the grid
where the entire 3-inch reflector (comprising the top portion of the
test object) was visible were recorded and combined to produce a
graphical rear field of view representation for the vehicle. Visible
areas around the vehicle were assessed for a 50th percentile male and
5th percentile female driver. These driver sizes were chosen to acquire
a range of visibility data in relation to driver height and because
they have been used by other organizations ^{87 88} in similar
visibility tests.
---------------------------------------------------------------------------

\86\ Mazzae, E.N., Light Vehicle Rear Visibility Assessment, DOT
HS 810 909, September 2008. NHTSA's visual target for this test was
a traffic cone with a reflector atop; its height is representative
of a 1-year-old child.
\87\ See also Consumer Reports (August, 2006). Blind-zone
measurements. http://www.consumerreports.org/cro/cars/safety-recalls/mind-that-blind-spot-1005/blindspot-measurements/index.htm.
Accessed 3/1/2006.
\88\ See also Paine, M., Macbeth, A., and Henderson, M. (2003).
The Danger to Young Pedestrians from Reversing Motor Vehicles. 18th
International Technical Conference on the Enhanced Safety of
Vehicles. Paper Number 466.
---------------------------------------------------------------------------

NHTSA observed that physical characteristics among drivers can
affect rear visibility. These characteristics include the occupant's
torso breadth, physical flexibility (e.g., torso and neck rotational
range), peripheral visual ability, visual acuity, and the presence of
eye glasses.\89\ Additional differences relating to driver positioning
while backing (e.g., raising the body up from the seat pan to achieve a
higher vantage point), driver preferences regarding seat adjustment,
and mirror positioning may also affect rear visibility. For example,
based on a review of test data, it appears that the particular 5th
percentile female driver involved in this testing may have been less
restricted in her body movement (i.e., leaned or ``craned'' body more)
when attempting to view the visual target. This resulted in a situation
that for some vehicles, the measured minimum sight distance and average
sight distance values were better for the shorter driver than for the
taller driver.
---------------------------------------------------------------------------

\89\ Note that when a driver wearing eye glasses turns to look
over their right shoulder to see behind their vehicle, there is a
point at which the line of sight can pass beyond the perimeter of
the lens, at which point the driver loses the aid of the corrective
lens.
---------------------------------------------------------------------------

NHTSA's Laser-Based Rear Visibility Measurement Procedure
NHTSA's rear visibility research conducted in 2008 began with an
effort to improve upon the previously used human-based rear visibility
measurement procedure. Since any compliance test for the Federal motor
vehicle safety standards is required by law to be repeatable and
reproducible, enhancements were focused on improving this aspect of the
measurement procedure. The agency considered known rear visibility
measurement procedures, built upon the work by Paine et al.,\90\ and
developed an enhanced version of that procedure that replaced the human
driver previously used in rear visibility measurements with a laser-
based fixture. The enhanced procedure approximated the direct rear
visibility of a vehicle for a 50th percentile male driver using a
fixture that incorporated two laser pointing devices to simulate a
driver's line of sight. One laser pointing device was positioned at the
midpoint of a 50th percentile male's eyes when looking rearward over
his left shoulder and the other device was placed at the midpoint of a
50th percentile male's eyes when looking rearward over his right
shoulder during backing.
---------------------------------------------------------------------------

\90\ Paine, M., Macbeth, A., and Henderson, M. (2003). The
Danger to Young Pedestrians from Reversing Motor Vehicles. 18th
International Technical Conference on the Enhanced Safety of
Vehicles. Paper Number 466.
---------------------------------------------------------------------------

The use of a laser pointing device to simulate driver sight line
was also used by Paine, et al.\91\ However, they used only a single eye
point that was approximately at the side of a 50th percentile male
driver's head. In addition, ISO 7397-2,\92\ which outlines a procedure
for verifying the driver's 180-degree forward direct field of view for
passenger cars, also uses a laser-based measurement technique. The use
of two representative eye points and a wider measurement area have been
proven to correlate well with backing crash risk \93\ and therefore may
result in a more valid measurement method.
---------------------------------------------------------------------------

\91\ Id.
\92\ ISO 7397-2, Passenger cars--Verification of driver's direct
field of view--Part 2: Test method, first edition, 1993-07-01.
\93\ Partyka, S., Direct-View Rear Visibility and Backing Risk
for Light Passenger Vehicles, (2008).
---------------------------------------------------------------------------

More details of NHTSA's revised rear visibility measurement
procedure using lasers are provided below.
1. Size of Rear Visibility Measurement Field
The size of the field over which rear visibility is measured should
encompass those areas critical to the avoidance of backover crashes. To
evaluate the dimensions of this field, NHTSA measured rear blind zone
area data for a variety of vehicles and compared these results with
backing crash data for those vehicles. In addition, a Monte Carlo
simulation analysis of relative backing crash risk as a function of
pedestrian location was performed. The results of these analyses are
summarized below.
Data analysis was performed to assess the correlation between
vehicles' rear blind zone areas measured using a 50th percentile male
driver and the backing crash data for 21 vehicles.\94\ Results of this
analysis for a portion of the field sizes assessed are summarized in
Table 10 (Appendix D contains a table summarizing the complete set of
areas assessed). Evidence of good correlation in this analysis is given
by high correlation coefficient values and a low probability of
occurrence by chance. All measurement field dimension combinations
listed in Table 10 show good correlation with backing crashes. A
similar preliminary analysis recently conducted by NHTSA using laser-
based rear blind zone areas measured for 60 vehicles over various
measurement field sizes showed a 50 feet square field to be better
correlated with backing crashes than narrower field size of the same
longitudinal dimension.
---------------------------------------------------------------------------

\94\ Mazzae, E.N., Light Vehicle Rear Visibility Assessment, DOT
HS 810 909, September 2008. NHTSA's visual target for this test was
a traffic cone with a reflector atop; its height is representative
of a 1-year-old child.

[[Page 9508]]

Table 10--Correlation Between Human-Based Rear Blind Zone Area Measured
Over Various Field Sizes and Backing Crashes (Sorted by Correlation
Coefficient)
------------------------------------------------------------------------
Probability
Measurement field dimensions (width by Correlation occurred by
length) coefficient chance
------------------------------------------------------------------------
50W x 10L............................... 0.60117 0.0039
40W x 10L............................... 0.60117 0.0039
30W x 10L............................... 0.58233 0.0056
30W x 50L............................... 0.55212 0.0095
40W x 40L............................... 0.54681 0.0103
30W x 40L............................... 0.53635 0.0122
20W x 40L............................... 0.52621 0.0143
50W x 50L*.............................. 0.52375 0.0148
20W x 50L............................... 0.52367 0.0148
------------------------------------------------------------------------
* Blind zone area measured over a field this size was found by
preliminary analysis of laser-based measurement data to be well
correlated with backing crashes.

Considering the assessment of backover crash risk by pedestrian
location described in Section IV.E of this notice, the results
presented in Figure 1 suggest that a measurement field centered behind
the vehicle and approximately 12 feet wide by 36 feet long would
address pedestrian locations having relative crash risks of 0.15 and
higher. Given that the analysis described in Appendix A suggests that
backover crash risk extends a fair distance (38 ft or more) out from
the vehicle, it may result in a more valid characterization of rear
visibility if a range similar to this were used for a rear visibility
measurement field.
For NHTSA's 2008 rear visibility measurement effort, a measurement
field of 50 feet long by 50 feet wide test area was used to ensure that
sufficient data were available for use in subsequent correlation
analyses relating measurement field and backing crashes. However, based
on a combination of the results of the three analyses summarized above,
a field size centered behind the vehicle and having the dimensions of
40 feet square or 50 feet is used on the analyses discussed in this
section.
2. Coarseness of the Rear Visibility Measurement Field's Test Grid
A measurement field covered by a test grid consisting of 1-foot
squares was used. This level of grid detail has provided meaningful
rear visibility data in past NHTSA testing, and has been used to
produce rear blind zone area data that have been successfully
correlated with backing crash risk.
3. Use of an H-Point Machine for Rear Visibility Measurement
To facilitate a repeatable test procedure, an H-Point machine,\95\
used by the agency for many other standards and representing a 50th
percentile adult male was used in place of a human driver for this
measurement effort. The 50th percentile adult male approximates the
midpoint for driver height, and has been used by other organizations
\96, 97\ conducting similar visibility measurement research. An H-Point
machine was selected to provide a standardized representation of the
seated posture of an adult male driver. The H-point machine's standard
configuration was modified to incorporate a fixture mounted in place of
the device's neck to hold the laser pointing devices in specific
positions to correspond to selected eye points for a 50th percentile
adult male driver (as described below).
---------------------------------------------------------------------------

\95\ SAE J826, Devices for Use in Defining and Measuring Vehicle
Seating Accommodation, Rev. JUL95.
\96\ See also Consumer Reports (August, 2006). Blind-zone
measurements. http://www.consumerreports.org/cro/cars/safety-recalls/mind-that-blind-spot-1005/blindspot-measurements/index.htm.
Accessed 3/1/2006.
\97\ See also Paine, M., Macbeth, A., and Henderson, M. (2003).
The Danger to Young Pedestrians from Reversing Motor Vehicles. 18th
International Technical Conference on the Enhanced Safety of
Vehicles. Paper Number 466.
---------------------------------------------------------------------------

4. Rear Visibility Measurement Test Object Height
NHTSA's rear visibility tests to date have been based on a test
object height representing the approximate height of a 1-year-old
child. As indicated earlier in this notice, 1-year-old children are the
most frequent (approximately 26 percent of all backovers) victims of
fatal backover incidents. The height chosen to represent a 1-year-old
child in NHTSA's tests to date was determined by averaging standing
height values from the Center for Disease Control's (CDC) growth chart
\98\ (see Table 11 below) for a male and female 1-year-old child. The
average height value obtained was 29.4 inches.
---------------------------------------------------------------------------

\98\ CDC, Clinical Growth Charts. Birth to 36 months: Boys;
Length-for-age and Weight-for-age percentiles. Published May 30,
2000 (modified 4/20/2001) CDC, Clinical Growth Charts. Birth to 36
months: Girls; Length-for-age and Weight-for-age percentiles.
Published May 30, 2000 (modified 4/20/2001).

Table 11--50th Percentile Child Height
--------------------------------------------------------------------------------------------------------------------------------------------------------
Age 1 2 3 4 5 6 7 8 9 10
--------------------------------------------------------------------------------------------------------------------------------------------------------
Height--Girl........................................... 29.125 33.5 37.2 39.5 42.5 45.25 47.75 50.25 52.2 54.5
Height--Boy............................................ 29.6 34 37.5 40.25 43 45.5 48 50.5 52.5 54.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: CDC, 2000.

5. Laser Detector (in Lieu of a Visual Target)
To improve the efficiency of our test procedure, NHTSA's rear
visibility measurement effort in 2008 used a different test object than
used in prior measurements. This new test object incorporates a laser
beam detector that automatically produces an audible signal when the
laser beam, simulating the driver's line of sight, intersects with the
laser detector. Since laser beams can

[[Page 9509]]

be difficult to detect with the human eye, even in low light
conditions, use of a laser beam detector would improve both the
accuracy and speed of test conduct.
The laser detector target was constructed with a commercial laser
detector mounted vertically on a post. The base of the post was a 12-
inch square of wood used to stabilize the fixture and center it within
a 1-foot grid square. The target's detection field was horizontally
centered with respect to the post and base. The bottom of the laser
detector's approximately 2-inch tall detection field was aligned at a
vertical height of 28 inches, to simulate a 30-inch overall detection
height.
For this approach to be usable and accommodate the 50 feet long
test grid and all possible lengths of vehicles to be measured, the
particular laser pointing device and laser beam detector were required
to have performance ranges of at least 70 feet.
An alternative approach, without a laser detector device, would be
to rely on a test operator to visually confirm that the laser beam
contacted the test object within the detection area while the test
object was positioned within a particular location on the test grid.
6. Eye Midpoint Locations for Use in Positioning Laser Pointing Devices
NHTSA researchers experimentally determined the most appropriate
locations for the lasers used to represent the line of sight for a
driver glancing over the right and left shoulder. Human eye locations
for three male drivers of 50th percentile height were determined using
photometric measurements while these drivers glanced at a cone
positioned 25 feet behind a vehicle and approximately at its centerline
and while looking directly (i.e., 90 degrees from forward) out the left
and right sides of the vehicle. Photographs were taken from the rear
and right (passenger) side of the vehicle for each of the three drivers
and three vehicles. Driver eye positions for each vehicle were
determined for both rear-looking glancing postures (rearward over the
left and right shoulders) and both side-looking glancing postures (left
and right). These eye positions were determined with respect to the
vehicles' seats using a scale of rigid rulers. Researchers calculated
an average left and right eye point locations to determine a midpoint
between the left and right eye for each of the four postures. These
midpoint values, which were used to identify locations of the laser
pointing device to simulate a driver's line of sight, are provided in
Table 12 below. NHTSA welcomes comments on the validity and
appropriateness of these eye points for use in evaluating a vehicle's
rear visibility for a 50th percentile male driver.

Table 12--Left-Right Eye Midpoint Locations for Posture of Driver Glancing Rearward and to Either Side
----------------------------------------------------------------------------------------------------------------
Longitudinal (distance
forward of the head Lateral offset from the Vertical with respect
Glancing rearward over the: restraint's vertical vertical centerline of to H-Point (in.) (z)
face) (in.) (x) the seat (in.) (y)
----------------------------------------------------------------------------------------------------------------
Left shoulder........................ 3.5 5.5 26.5 \*\
Right shoulder....................... 5.3 7.0 26.5 \*\
Left window (-90 degrees from 7.6 -5.5 26.5 \*\
forward)............................
Right window (90 degrees from 7.6 5.0 26.5 \*\
forward)............................
----------------------------------------------------------------------------------------------------------------
\*\ Note: These measurements assume that the distance from the seat pan to the H-Point is 3.6 inches.

7. Vehicle Setup
Vehicle setup conditions may be an important part of a repeatable
visibility measurement procedure. Considerations which we used for our
recent, laser-based measurements are detailed below.
Fuel Tank--Ensure that the vehicle's fuel tank is filled to
capacity, to provide a consistent fuel level (can affect vehicle
pitch).
Vehicle Tires--The vehicle's tires should be set to their
recommended inflation pressures (can affect vehicle pitch).
Vehicle Position on Test Grid--Position the vehicle on a flat,
level test grid such that it is properly aligned (i.e., rear bumper
flush with the `0' foot line, vehicle centered on the `0' longitudinal
axis of the test grid).
Vehicle Windows--The vehicle's windows should be closed, clean, and
clear of obstructions (e.g., window stickers).
H-Point Device Configuration--Place the H-Point device in the
driver's seat and adjust the seat as follows:
Install the H-Point machine in the vehicle per the
installation procedure outlined in SAE J826.\99\
---------------------------------------------------------------------------

\99\ SAE J826, Devices for Use in Defining and Measuring Vehicle
Seating Accommodation, Rev. JUL95.
---------------------------------------------------------------------------

Adjust the driver's seat to the longitudinal adjustment
position recommended by the manufacturer for a 50th percentile adult
male as specified in FMVSS Nos. 208,\100\ 212,\101\ 219 (partial),\102\
and 301 \103\ compliance testing. If this recommended adjustment
setting is not available, position the seat at the midpoint of the
longitudinal adjustment range. If no midpoint is selectable, then
position the seat at the first notch rearward of the midpoint.
---------------------------------------------------------------------------

\100\ 49 CFR 571.208, Standard No. 208; Occupant crash
protection.
\101\ 49 CFR 571.212, Standard No. 212; Windshield mounting.
\102\ 49 CFR 571.219, Standard No. 219; Windshield zone
intrusion.
\103\ 49 CFR 571.301, Standard No. 301; Fuel system integrity.
---------------------------------------------------------------------------

Adjust the driver's seat to the vertical adjustment
position recommended by the manufacturer for a 50th percentile adult
male as specified in FMVSS Nos. 208, 212, 219 (partial), and 301
compliance testing. If this recommended adjustment setting is not
available, position the seat at the lowest point of all vertical
adjustment ranges present.
Use the H-Point machine to adjust the driver's seat back
angle at the vertical portion of the H-Point machine's torso weight
hanger to that recommended by the manufacturer for a 50th percentile
adult male as specified in FMVSS 208, 212, 219 (partial), and 301
compliance testing. If this recommended adjustment setting is not
available, adjust the seat back angle to 25 degrees, as specified in
SAE J826.
Adjust the driver's seat head restraint such that the
distance from the H-Point to the topmost point of the head restraint,
as measured along a line parallel to the seat back, is 32.5
inches.\104\ If a distance of 32.5 inches is not attainable given the
adjustment range of the head restraint or detent

[[Page 9510]]

positions, the closest detent position to that height should be used.
---------------------------------------------------------------------------

\104\ This 32.5 inch measurement is based on sitting height of
36.3 inches for 50th percentile adult males aged 20 and over. See
CDC Web site at: http://www.cdc.gov/nchs/about/major/nhanes/anthropometric_measures.htm.
---------------------------------------------------------------------------

For any head restraints with longitudinal adjustment, the
restraint should be positioned fully forward.
Vehicle Seat Positioning--Adjust all seats in positions other than
the driver's as follows:
Vehicles with standard stowable second or third row seats
should have all seats in an upright, occupant-ready position. This
configuration provides a consistent approach for rear seat positioning
to avoid vehicle-to-vehicle test differences. If a vehicle is offered
with an optional original equipment third row seat, the vehicle should
be measured in this seating configuration to assess the vehicle's rear
visibility characteristics in this worst-case condition.
For seats with longitudinally adjustable head restraints,
the restraint should be positioned at the midpoint of longitudinal
adjustment
For seats with vertically adjustable head restraints, the
restraint should be positioned in the lowest possible position. This
configuration provides a consistent approach for head restraint
positioning to avoid vehicle-to-vehicle test differences.
For seats with an adjustable seat back angle, adjust the
seat back angle to that recommended by the manufacturer for a driver's
seat back angle position for a 50th percentile adult male as specified
in FMVSS 208, 212, 219 (partial), and 301 compliance testing. If this
recommended driver's seat back angle setting is not available, adjust
the seat back angle to 25 degrees.
Any rear seating position shoulder belts originating from
the headliner (e.g., for use in rear center seating positions) should
be latched into their receivers at the seat bite.
8. Measurement Procedure
Once the vehicle has been properly set and the laser fixture has
been set up, the laser devices are turned on and a pre-test is
performed. To ensure that the laser device and laser detector are
capable of performing the test, the laser device shall be properly
mounted at the required driver eye point position (as indicated in
Table 12), and aimed at the laser detector test object which shall be
centered at a distance of 50 feet aft of the vehicle's bumper to
determine whether the laser detector is able to sense the laser beam.
This confirmation pre-test shall also be performed for the laser
detector test object positioned at a distance of 50 feet from the rear
bumper and 25 feet laterally to either side of the vehicle. If the
laser detector detects the laser beam (e.g., as indicated by a ``beep''
or other confirming signal) in each of these three locations, then the
equipment is considered to perform at an acceptable level for use in
this test procedure.
To complete the rear visibility measurements, the laser devices
while maintaining the x, y, z coordinates may be manually or
automatically maneuvered to pan the area behind the vehicle in both the
vertical and horizontal directions. The vertical extent of the laser
beam movement shall extend from the lower edge of the rear window to
the horizon. The horizontal range of laser motion shall permit the
evaluation of the direct visibility of the test object as positioned
within 1 foot of the rear bumper and 25 feet to both sides of the
vehicle's centerline.
The test object is placed on the grid one time in each 1-foot
square behind the vehicle. The test observer listens to determine
whether the laser detector beeps (or otherwise signals) to indicate
that the detector field has been contacted by a laser beam. The test
object is considered visible if the laser detector beeps when a laser
beam intersects with the test object. An operator records this
measurement and repeats the prior steps for all positions in the grid.
Observations About Available Rear Visibility Measurement Procedures
The above descriptions summarize NHTSA's knowledge of existing
procedures for measuring vehicles' rear visibility. NHTSA seeks
comments on the utility of these methods as objective rear visibility
assessment methods.
While the noted laser-based measurement method appears to provide a
robust, objective test method, the repeatability of the method must be
confirmed. Therefore, to further assess the utility of our laser-based
rear visibility measurement procedure, we also assessed the
repeatability of the test method as described in the following section.

B. Rear Visibility Measurement Method Variability

To assess the variability of NHTSA's improved rear visibility test
method using laser pointing devices, four test vehicles were measured
using the laser-based rear visibility measurement protocol. The
measurement procedure was completed four times for each vehicle,
including repositioning of the vehicle on the test grid. Results of
these measurements are illustrated in Figure 13. As indicated in Table
13, the rear blind zone area data varied less than 3.2 percent of the
measured value. This variability is believed to be due to the test
vehicle's alignment of the rear bumper with respect to the lateral grid
axis. More carefully aligning the vehicle on the test grid to ensure
that the vehicle's centerline is aligned with the test grid's
longitudinal axis will likely reduce variation to 2 percent or less.

[[Page 9511]]

[GRAPHIC] [TIFF OMITTED] TP04MR09.012

Table 13--Rear Blind Zone Area Measurement Repeatability Results and Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
Std dev/
Vehicle Test 1 Test 2 Test 3 Test 4 Avg Std. Min Max Range (max- avg
dev. min) (percent)
--------------------------------------------------------------------------------------------------------------------------------------------------------
2005 Chrysler 300C...................................... 1608 1631 1590 1604 1608 17.0 1590 1631 41 1.1
2006 BMW 330i........................................... 1523 1542 1533 1513 1528 12.5 1513 1542 29 0.8
2007 Cadillac Escalade.................................. 1863 1800 1889 1887 1860 41.5 1800 1889 89 2.2
2007 Honda Odyssey...................................... 1783 1834 1705 1739 1765 55.9 1705 1834 129 3.2
--------------------------------------------------------------------------------------------------------------------------------------------------------

In summary, this rear visibility measurement procedure seems to
provide for a controlled vehicle setup (for test consistency and
repeatability) by its use of an automated test object, and dynamic
laser movement.

C. Comparison of Human-Based Versus Laser-Based Rear Visibility
Measurement Protocols

NHTSA compared rear visibility data for 18 vehicles that were
measured using both the human-based and laser-based rear visibility
measurement procedures to assess the results (i.e., similar vehicle
rankings, etc.) of the test procedure under consideration. This
comparison found data from the two measurement methods to be different
but correlated to a statistically significant degree.

D. Input From Industry Regarding Rear Visibility Measurement

NHTSA received input from the Alliance for Automotive Manufacturers
regarding the method for assessment for the purposes of assessing the
need for a rear visibility enhancement countermeasure. The Alliance
suggested a protocol similar to that used in FMVSS No. 111 for the
measurement of the field of view of the interior rear mirror.\105\ This
protocol would use a 95th percentile male driver. No additional details
regarding a rear visibility measurement procedure were provided by the
Alliance or any other group.
---------------------------------------------------------------------------

\105\ Presentation to NHTSA, January 28, 2009 meeting; Alliance
for Automotive Manufacturers. Available at Docket Number 2009-0041.
---------------------------------------------------------------------------

E. Questions

(1) While a 50th percentile male body size was used for the rear
visibility measurements outlined here, we note that FMVSS No. 111
currently requires that the driver's eye reference point be at a
nominal location appropriate for any 95th percentile male driver for
the assessment of rearview mirror field of view compliance. We further
note that under FMVSS No. 111 the driver's eye location for school bus
mirror compliance testing is the eye location of a 25th percentile
female driver. NHTSA requests comment on the use of the 50th percentile
male driver size as a midpoint in terms of driver height and whether
using multiple driver heights for these tests would cause undue
hardship relative to the safety value of assessing different driver
heights. Specific information regarding

[[Page 9512]]

additional cost, if any, that would be incurred by vehicle
manufacturers due to the use of different driver sizes for these
different portions of FMVSS No. 111 is requested.
(2) NHTSA has been using seating position settings recommended by
the vehicle manufacturers for agency crash tests. For most vehicles,
the vertical seat position setting recommended for seats with vertical
adjustability is the lowest position. NHTSA seeks comment on whether
this setting is the most suitable position for a 50th percentile male,
or if a midpoint setting would be more appropriate for measuring rear
visibility. NHTSA also seeks comment on whether the specific crash test
seating specifications used are the most appropriate for this context.
(3) NHTSA seeks comment on the placements of head restraints. For
example, would our test procedure result in the elimination of rear
head restraints or a reduction in their size? If so, please identify
the affected vehicles and explain why the rear head restraints
particularly impair visibility in those vehicles. Similarly, NHTSA
seeks comment on the approach to setting the longitudinal position of
all adjustable head restraints for rear visibility measurements. While
longitudinally adjustable head restraints positioned fully forward may
minimize the chance of whiplash, a more reasonable option for this test
may be to position the head restraint at the midpoint of the
longitudinal adjustment range.
(4) In our testing, we found that the laser beam is difficult to
detect visually. Therefore, we used the laser detector. NHTSA invites
comment on the availability of other options for detecting the laser
beam as used in this test that does not involve the use of an
electronic laser detector.
(5) For locating the laser devices at the selected driver eye
points, is there another device besides the H-point device which can be
utilized for this purpose or should the agency? For simplicity, should
eye points be indicated in a similar fashion as is currently in FMVSS
No. 111 for school bus testing in which a single eye point is located
at a specified distance from the seat cushion/seat back intersection
and within a 6-inch semi-circular area?

XI. Options for Assessing the Performance of Rear Visibility
Countermeasures

To assess the minimum performance of a required rear visibility
enhancement countermeasure, a compliance test would need to be
developed. This test would serve to assess whether the system permits
obstacles and standing children in the path of a backing vehicle to be
detected over a minimum required area. Considerations that the agency
has identified which may be necessary for this new compliance test are
described below.

A. Countermeasure Performance Test Object

A test object may be needed to assess whether the countermeasure
functions over a specified area. Based on the crash data and our
testing to date, we have used a test object with an approximate height
of 30 inches (0.762 meters). As indicated earlier, this height
corresponds to the average height of a 1-year-old child. To further
simulate the appearance of a 1-year-old child, some have suggested
other dimensional characteristics. Based on our research we have found
that that the object would need to be cylindrical in shape with a
diameter of 5 inches, to represent the breadth of the average 1-year-
old child's head.\106\
---------------------------------------------------------------------------

\106\ Henry Dreyfuss Associates (2002). The Measure of Man and
Woman; Human Factors in Design (rev.). New York: John Wiley & Sons.
---------------------------------------------------------------------------

Depending on the type of countermeasure, the composition of the
test object may be important. For example, rearview video systems would
display images of objects of all possible material types, but
ultrasonic and radar sensors are better at detecting some materials
than others. NHTSA is aware of the requirement detailed in ISO 17386
\107\ for use of a cylinder composed of polyvinyl chloride (PVC) pipe
to test the detection performance of ultrasonic parking aids. NHTSA
welcomes input regarding all aspects of the test object.
---------------------------------------------------------------------------

\107\ ISO 17386:2004 Transport information and control systems--
Manoeuvring Aids for Low Speed Operation (MALSO)--Performance
requirements and test procedures.
---------------------------------------------------------------------------

The Alliance for Automotive Manufacturers has indicated to NHTSA
that their suggestion is to use a cylindrical test object with a height
of 1 meter (39.37 inches) and a diameter of 0.3 meters (11.3
inches).\108\ No requirements for material composition of the test
object were suggested by the Alliance.
---------------------------------------------------------------------------

\108\ Presentation to NHTSA, January 28, 2009 meeting; Alliance
for Automotive Manufacturers. Available at Docket Number 2009-0041.
---------------------------------------------------------------------------

B. Countermeasure Performance Test Area

One possible compliance test area can be identified using the
results of the Monte Carlo simulation (illustrated in Figure 1 and
described in Appendix A) that examined backover crash risk as a
function of a pedestrian's location behind a vehicle.\109\ NHTSA used
these results to define an area behind a vehicle that must be visible
to the driver. Based on these results, an area over which the test
object should be visible could be defined to include an area 8 feet
wide at the vehicle's rear bumper that widens symmetrically along
diagonal lines of 45 degrees with respect to the vertical plane of the
vehicle's rear bumper and extending outward from the vehicle's rear
corners. The maximum longitudinal range of this required visible area
is 40 feet, as shown in Figure 14.
---------------------------------------------------------------------------

\109\ See Appendix B, Method for Assessment of Backover Crash
Risk by Pedestrian Location.
---------------------------------------------------------------------------

BILLING CODE 4910-59-P

[[Page 9513]]

[GRAPHIC] [TIFF OMITTED] TP04MR09.013

BILLING CODE 4910-59-C

[[Page 9514]]

Alternatively, the test area could be defined based on the results
of the above mentioned Monte Carlo analysis, as well as the assessments
of the correlation between vehicles' rear blind zone areas and backing
crash data. The test area suggested by the combination of results of
these three analyses is one that is centered behind the vehicle and
having the dimensions of 40 feet square or 50 feet square.
The Alliance for Automotive Manufacturers has indicated to NHTSA
that their suggestion is to use a test area composed of 9 test object
locations behind the vehicle.\110\ The 9 test object locations would
consist of 3 rows of 3 locations. The 3 rows would be positioned with
one at the rear bumper, and two others positioned 1.5 meters and 3.0
meters aft of the rear bumper. The 3 lateral locations would consist of
one at each lateral edge of the vehicle and the third at the vehicle's
longitudinal centerline. By this scheme, the test area size would be
based on each vehicle model's individual width, and therefore may be
different for all vehicle models.
---------------------------------------------------------------------------

\110\ Presentation to NHTSA, January 28, 2009 meeting; Alliance
for Automotive Manufacturers. Available at Docket Number 2009-0041.
---------------------------------------------------------------------------

C. Countermeasure Performance Test Procedure

The test procedure currently used for school bus mirrors (section
13, ``School bus mirror test procedures'' of FMVSS No. 111, ``Rearview
mirrors'') \111\ could be modified and used to determine countermeasure
performance. For example, a still photography camera placed with the
imaging sensor located at a midpoint eye location for a 50th percentile
male (rather than a 95th percentile male), could be used to photograph
the test objects as they are displayed in the countermeasure system's
visual display. As is done now with cones in rear visibility
measurements, for all specified locations of the test object on the
test grid, at least a 3-inch tall by 3-inch wide portion of the test
object would be required to be visible in order for the rear visibility
enhancement system to be deemed compliant. This minimum detection area
would represent the area that would need to be visible to adequately
identify the test object.
---------------------------------------------------------------------------

\111\ 49 CFR 571.111, Standard No. 111, Rearview Mirrors.
---------------------------------------------------------------------------

D. Questions

(1) NHTSA invites comments on the need for and adequacy of the
described area which rear visibility countermeasure systems may be
required to detect obstacles. NHTSA is particularly interested in any
available data that may suggest an alternative area behind the vehicle
over which a rear visibility enhancement countermeasure should be
effective? Is the described area of coverage unrealistically large? Is
it adequate to mimic real world angles at which children may approach
vehicles?
(2) Is it reasonable to define the limits of the test zone such
that it begins immediately behind the rear bumper for the test object
defined here or should a gap be permitted before the visibility zone
begins? What additional factors should the agency consider in defining
the zone?
(3) NHTSA requests comments on potentially requiring only the
perimeter of the specified area to be tested for rear visibility
enhancement systems. For video-based rear visibility countermeasure
systems, NHTSA assumes that confirming the visibility of the test
object over the perimeter of the required area is sufficient, since a
system able to display the object at the perimeter of the required area
should also be able to display the object at all points in between the
extremities. Is this a reasonable assumption?
(4) Would vehicles with rearview video cameras mounted away from
the vehicle centerline have the ability to detect the test object over
the area under consideration? Is there flexibility to relocate such
off-center cameras to meet the requirements under consideration, if
necessary?
(5) NHTSA seeks comment as to the availability of any mirrors that
may have a field of view that encompasses a range of 50 feet, as well
as the quality of image that might be provided over such a range. How
different is the image size and resolution, and how significant are the
differences to the mirrors' potential effectiveness?
(6) If a gap is permitted behind the vehicle before the visibility
zone begins, how will systems prevent children who may be immediately
behind a vehicle from being backed over?
(7) NHTSA seeks input on what level of ambient lighting would be
appropriate to specify for conduct of this compliance test. What other
environmental and ambient conditions, if any, should the agency include
in the test procedure?
(8) NHTSA invites input regarding the composition of the
countermeasure compliance test object and the types of technologies
that are likely to be able to provide coverage of the related test
area.

XII. Options for Characterizing Rear Visibility Countermeasures

Existing rear visibility technologies, which formed the basis for
NHTSA's effectiveness estimates, already contain certain performance
levels specified by vehicle manufacturers. Some of these specifications
may be necessary to ensure that our effectiveness estimates will be
applicable to real-world crashes and to prevent for inferior systems
from entering the fleet. However, NHTSA is not aware of consensus
industry specifications (e.g., SAE standards) or published recommended
practices for rear visibility enhancement systems other than mirrors
that may serve this purpose. While FMVSS No. 111 contains performance
specifications for convex mirrors, the mirror specifications contained
therein may not be adequate for this application. As such, certain
performance specifications may be necessary in order to ensure adequate
system effectiveness. NHTSA solicits comment on whether the performance
aspects we have identified are appropriate or whether additional
specifications, particularly for electronic image-based visual
displays, should be considered. NHTSA has not evaluated these
performance specifications nor have we developed possible compliance
tests for them.

A. Options for Display Characteristics

Given that a particular rear visibility countermeasure technology
has not been specified, the type of visual display associated with a
rear visibility countermeasure has the potential to take a variety of
forms. Such visual displays may include mirrors, flashing lights from
sensor-based rear object detection system, or a video-based image
display. Some characteristics relevant to possible visual display types
are described below.
Performance Criteria Which May be Needed for All Rear Visibility
Enhancement Countermeasure Displays (e.g., Rearview Video System
Displays, Mirrors, and Electronic Warning Displays)
Overall display size--The minimum overall image size should be
defined to ensure that drivers will be able to detect small children in
the visual display. If the image size is too small, the effectiveness
of the system may be impacted by a driver's inability to identify a
child or other object.
Image resolution--It may be necessary to define the minimum image
resolution so that drivers will be able to identify objects in the
display.
Image distortion--A maximum allowable distortion parameter may be

[[Page 9515]]

necessary to ensure that image quality is sufficient to allow drivers
to accurately identify objects located behind the vehicle.
Image minification--To ensure that objects behind the vehicle
appear in the image of the area behind the vehicle as presented by the
countermeasure's display with sufficient size to allow them to be
identified by drivers, a maximum allowable minification level may be
necessary.
Environmental performance--It may be necessary to specify minimum
environmental requirements under which systems would be expected to
operate in common real world conditions.
Additional Performance Criteria Which May be Needed for Electronic
Visual Displays (e.g., Rearview Video Systems, Electronic Warning
Displays)
Display location--In order to facilitate a driver's effective use
of an electronic visual display, it may be beneficial to specify a
permitted location for the display unit and image. For example, a
rearview video image present in the interior rearview mirror must be
displayed on the left side of the mirror so that the distance between
the driver and image is not too large.
Overall display size--For electronic, rearview video system
displays, NHTSA is considering specifying a minimum image size of 3.25
inches measured diagonally for an electronic visual display with aspect
ratio of 4:3 \112\ (or approximately 4-inch diagonal size for 16:9
aspect ratio displays).
---------------------------------------------------------------------------

\112\ General Motors, SAE Government and Industry Meeting, May
2008, oral presentation.
---------------------------------------------------------------------------

Brightness--A minimum brightness value \113\ may be necessary to
ensure that the display image can be seen by drivers in a wide variety
of ambient conditions, such as glare from sunlight or ambient light.
---------------------------------------------------------------------------

\113\ Measured in cd/m\2\.
---------------------------------------------------------------------------

Contrast ratio--Minimum contrast ratio may be necessary to ensure
that the display image can be seen by drivers in a wide variety of
ambient conditions.
Image response time--A minimum response time for the system to
display an image of the area behind the vehicle may be necessary to
enable a driver to engage the system while backing. NHTSA is
considering a maximum of 1.25 seconds based on our research to
date.\114\
---------------------------------------------------------------------------

\114\ Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and
Ranney, T.A. (2008). On-Road Study of Drivers' Use of Rearview Video
Systems (ORSDURVS). National Highway Traffic Safety Administration,
DOT 811 024.
---------------------------------------------------------------------------

Image ``linger'' time--To limit unintended distraction to drivers,
the maximum image linger time (i.e., the time that the visual display
remains on after the vehicle's transmission has been shifted out of
reverse gear), may be specified. Some linger time is desirable for
situations where frequent transitions from reverse to forward gear are
needed to adjust a vehicle's position (e.g., parallel parking and
hitching). NHTSA is considering a minimum of 4 seconds but not more
than 8 seconds of linger time is appropriate after the vehicle is
shifted from the reverse position.

Options for Other Display Characteristics

NHTSA does not believe that a malfunction telltale is necessary for
rearview video systems, since video camera or visual display failure
would be indicated by the apparent lack of image presented in the
visual display. We invite comments on this point and any evidence that
would suggest that such an indicator may be necessary.

B. Options for Rearview Video System Camera Characteristics

Currently, NHTSA does not have data which could be used to
establish minimum specifications for a rearview video system's camera.
However, based upon our knowledge of the current technology the agency
believes that requirements for the following categories might be
necessary: Low light performance requirements; resolution; and
environmental performance limits/ranges.

C. Questions

(1) Are there any existing industry consensus standards for rear
visibility enhancement systems which address the parameters outlined in
this section? Are there any ongoing efforts to develop such industry
consensus standards? If so, when will the standards be published?
(2) Are there additional parameters which should be specified to
define a rear visibility enhancement system? What should the minimum
specified performance be for each parameter?
(3) Are future rear visibility systems anticipated which may have
significantly different visual display types that may require other
display specification parameters?

XIII. Conclusion

In developing this notice, NHTSA tried to address the concerns of
all stakeholders. Your comments will help us develop a rearward
visibility standard to be included as part of FMVSS No. 111. We invite
you to provide different views on the questions we ask, new approaches
and technologies about which we did not ask, new data, insight as to
how this notice may affect you, or other relevant information. We
welcome your views on all aspects of this notice but we especially
request comments on the specific questions articulated throughout this
document.

XIV. Public Participation

How do I prepare and submit comments?

Your comments must be written and in English. To ensure that your
comments are correctly filed in the Docket, please include the docket
number of this document in your comments.
Your comments must not be more than 15 pages long. (49 CFR 553.21).
We established this limit to encourage you to write your primary
comments in a concise fashion. However, you may attach necessary
additional documents to your comments. There is no limit on the length
of the attachments.
Please submit two copies of your comments, including the
attachments, to Docket Management at the address given above under
ADDRESSES.
Comments may also be submitted to the docket electronically by
logging onto the Docket Management System Web site at http://www.regulations.gov. Follow the online instructions for submitting
comments.
Please note that pursuant to the Data Quality Act, in order for
substantive data to be relied upon and used by the agency, it must meet
the information quality standards set forth in the OMB and DOT Data
Quality Act guidelines. Accordingly, we encourage you to consult the
guidelines in preparing your comments. OMB's guidelines may be accessed
at http://www.whitehouse.gov/omb/fedreg/reproducible.html. DOT's
guidelines may be accessed at http://dms.dot.gov.

How can I be sure that my comments were received?

If you wish Docket Management to notify you upon its receipt of
your comments, enclose a self-addressed, stamped postcard in the
envelope containing your comments. Upon receiving your comments, Docket
Management will return the postcard by mail.

How do I submit confidential business information?

If you wish to submit any information under a claim of
confidentiality, you should submit three copies of your complete
submission, including the information you claim to be confidential

[[Page 9516]]

business information, to the Chief Counsel, NHTSA, at the address given
above under FOR FURTHER INFORMATION CONTACT. In addition, you should
submit two copies, from which you have deleted the claimed confidential
business information, to Docket Management at the address given above
under ADDRESSES. When you send a comment containing information claimed
to be confidential business information, you should include a cover
letter setting forth the information specified in our confidential
business information regulation. (49 CFR Part 512.)

Will the agency consider late comments?

We will consider all comments that Docket Management receives
before the close of business on the comment closing date indicated
above under DATES. To the extent possible, we will also consider
comments that Docket Management receives after that date. If Docket
Management receives a comment too late for us to consider in developing
a final rule (assuming that one is issued), we will consider that
comment as an informal suggestion for future rulemaking action.

How can I read the comments submitted by other people?

You may read the comments received by Docket Management at the
address given above under ADDRESSES. The hours of the Docket are
indicated above in the same location. You may also see the comments on
the Internet. To read the comments on the Internet, go to http://www.regulations.gov. Follow the online instructions for accessing the
dockets.
Please note that even after the comment closing date, we will
continue to file relevant information in the Docket as it becomes
available. Further, some people may submit late comments. Accordingly,
we recommend that you periodically check the Docket for new material.

XV. Rulemaking Analyses and Notices

Executive Order 12866 and DOT Regulatory Policies and Procedures

Executive Order 12866, ``Regulatory Planning and Review'' (58 FR
51735, October 4, 1993), provides for making determinations whether a
regulatory action is ``significant'' and therefore subject to OMB
review and to the requirements of the Executive Order. The Order
defines a ``significant regulatory action'' as one that is likely to
result in a rule that may:
(1) Have an annual effect on the economy of $100 million or more or
adversely affect in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or State, local, or Tribal governments or
communities;
(2) Create a serious inconsistency or otherwise interfere with an
action taken or planned by another agency;
(3) Materially alter the budgetary impact of entitlements, grants,
user fees, or loan programs or the rights and obligations of recipients
thereof; or
(4) Raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
the Executive Order.
We have considered the potential impact of this ANPRM under
Executive Order 12866 and the Department of Transportation's regulatory
policies and procedures. As discussed above, there are a number of
considerations and technologies that can be applied to address the
issue of backovers and the agency lacks the necessary information to
develop a proposal at this time. Based on the information we have, we
developed this notice and placed in the docket a Preliminary Regulatory
Impact Analysis to facilitate public input. Therefore, we have not yet
determined whether or not this rulemaking will be economically
significant under Executive Order 12866. However, this rulemaking
action has been determined to be ``significant'' under the Department
of Transportation's Regulatory Policies and Procedures (44 FR 11034;
February 26, 1979) and has been reviewed by the Office of Management
and Budget.

Regulatory Flexibility Act

Pursuant to the Regulatory Flexibility Act, 5 U.S.C. 601 et seq.,
no analysis is required for an ANPRM. However, vehicle manufacturers
and equipment manufacturers are encouraged to comment if they identify
any aspects of the potential rulemaking that may apply to them.

Executive Order 13132 (Federalism)

NHTSA has examined today's ANPRM pursuant to Executive Order 13132
(64 FR 43255, August 10, 1999) and concluded that no additional
consultation with States, local governments or their representatives is
mandated beyond the rulemaking process at this time. The agency has
concluded that the document at issue does not have federalism
implications because it does not have ``substantial direct effects on
the States, on the relationship between the national government and the
States, or on the distribution of power and responsibilities among the
various levels of government.''
NHTSA's safety standards can have preemptive effect in at least two
ways. First, the National Traffic and Motor Vehicle Safety Act contains
an express preemption provision: ``When a motor vehicle safety standard
is in effect under this chapter, a State or a political subdivision of
a State may prescribe or continue in effect a standard applicable to
the same aspect of performance of a motor vehicle or motor vehicle
equipment only if the standard is identical to the standard prescribed
under this chapter.'' 49 U.S.C. 30103(b)(1). It is this statutory
command that would unavoidably preempt State legislative and
administrative law, not today's rulemaking, so consultation would be
unnecessary.
We are aware that, depending on the nature of the proposal
ultimately adopted, federalism implications could arise. Currently,
there is no Federal requirement regarding visibility of the area
directly behind a passenger vehicle. As a result, any State laws or
regulations that seek to regulate this aspect of performance would not
currently be preempted by Federal law. However, if NHTSA issues a
standard on the same aspect of performance, those State laws and
regulations would be preempted if they differed from the Federal
requirements. Thus, the possibility of statutory preemption of State
laws and regulations does exist. At this time, we do not know of any
State laws or regulations that currently exist that are potentially at
risk of being preempted, but in this document do request comment on any
existing or planned laws or regulations that would fall into this
category.
Second, the Supreme Court has recognized the possibility of implied
preemption: State requirements imposed on motor vehicle manufacturers,
including sanctions imposed by State tort law, can stand as an obstacle
to the accomplishment and execution of a NHTSA safety standard. When
such a conflict is discerned, the Supremacy Clause of the Constitution
makes the State requirements unenforceable. See Geier v. American Honda
Motor Co., 529 U.S. 861 (2000). NHTSA has considered today's ANPRM and
does not currently foresee any potential State requirements that might
conflict with it. Without any conflict, there could not be any implied
preemption.

Executive Order 12988 (Civil Justice Reform)

With respect to the review of the promulgation of a new regulation,

[[Page 9517]]

section 3(b) of Executive Order 12988, ``Civil Justice Reform'' (61 FR
4729, February 7, 1996) requires that Executive agencies make every
reasonable effort to ensure that the regulation: (1) Clearly specifies
the preemptive effect; (2) clearly specifies the effect on existing
Federal law or regulation; (3) provides a clear legal standard for
affected conduct, while promoting simplification and burden reduction;
(4) clearly specifies the retroactive effect, if any; (5) adequately
defines key terms; and (7) addresses other important issues affecting
clarity and general draftsmanship under any guidelines issued by the
Attorney General. This document is consistent with that requirement.
Pursuant to this Order, NHTSA notes as follows. The preemptive
effect of this document is discussed above. NHTSA notes further that
there is no requirement that individuals submit a petition for
reconsideration or pursue other administrative proceeding before they
may file suit in court.

Protection of Children From Environmental Health and Safety Risks

Executive Order 13045, ``Protection of Children from Environmental
Health and Safety Risks'' (62 FR 19855, April 23, 1997), applies to any
rule that: (1) Is determined to be ``economically significant'' as
defined under Executive Order 12866, and (2) concerns an environmental,
health, or safety risk that the agency has reason to believe may have a
disproportionate effect on children. If the regulatory action meets
both criteria, the agency must evaluate the environmental health or
safety effects of the planned rule on children, and explain why the
planned regulation is preferable to other potentially effective and
reasonably feasible alternatives considered by the agency.
While this document does not make any changes with regard to the
standard at issue, the rulemaking is intended, in large part, to
address a safety concern that is particularly applicable to young
children. In response to the executive order and in alignment with the
agency's policies, we have tailored our research efforts addressed in
this document to be particularly sensitive to the needs of children.
These steps have included, but are not limited to, analyzing accident
cases that involve children and designing testing procedures and
performance criteria with particular emphasis on the ultimate goal of
detecting and preventing accidents involving the youngest children.

Paperwork Reduction Act

Under the Paperwork Reduction Act of 1995 (PRA), a person is not
required to respond to a collection of information by a Federal agency
unless the collection displays a valid OMB control number. There is not
any information collection requirement associated with this ANPRM.

National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (NTTAA), Public Law 104-113, (15 U.S.C. 272) directs the
agency to evaluate and use voluntary consensus standards in its
regulatory activities unless doing so would be inconsistent with
applicable law or is otherwise impractical. Voluntary consensus
standards are technical standards (e.g., materials specifications, test
methods, sampling procedures, and business practices) that are
developed or adopted by voluntary consensus standards bodies, such as
the Society of Automotive Engineers. The NTTAA directs us to provide
Congress (through OMB) with explanations when we decide not to use
available and applicable voluntary consensus standards. There are no
voluntary consensus standards developed by voluntary consensus
standards bodies pertaining to this ANPRM.

Unfunded Mandates Reform Act

The Unfunded Mandates Reform Act of 1995 requires agencies to
prepare a written assessment of the costs, benefits and other effects
of proposed or final rules that include a Federal mandate likely to
result in the expenditure by State, local or tribal governments, in the
aggregate, or by the private sector, of more than $100 million annually
(adjusted for inflation with base year of 1995). This ANPRM would not
result in expenditures by State, local or tribal governments, in the
aggregate, or by the private sector in excess of $100 million annually.
However, given the cost estimates of some of the technologies at issue,
most relevantly RV video systems, it is very possible that the total
cost of a proposed rule could substantially exceed $100 million. Given
that, the agency has prepared a preliminary assessment of some of the
possible costs of the technologies investigated in this ANPRM.

National Environmental Policy Act

NHTSA has analyzed this rulemaking action for the purposes of the
National Environmental Policy Act. The agency has determined that
implementation of this action will not have any significant impact on
the quality of the human environment.

Executive Order 13211

Executive Order 13211 (66 FR 28355, May 18, 2001) applies to any
rulemaking that: (1) Is determined to be economically significant as
defined under E.O. 12866, and is likely to have a significantly adverse
effect on the supply of, distribution of, or use of energy; or (2) that
is designated by the Administrator of the Office of Information and
Regulatory Affairs as a significant energy action. This rulemaking is
not subject to E.O. 13211.

Plain Language

Executive Order 12866 and the President's memorandum of June 1,
1998, require each agency to write all rules in plain language.
Application of the principles of plain language includes consideration
of the following questions:
Have we organized the material to suit the public's needs?
Are the requirements in the rule clearly stated?
Does the rule contain technical language or jargon that
isn't clear?
Would a different format (grouping and order of sections,
use of headings, paragraphing) make the rule easier to understand?
Would more (but shorter) sections be better?
Could we improve clarity by adding tables, lists, or
diagrams?
What else could we do to make the rule easier to
understand?
If you have any responses to these questions, please include them
in your comments on this ANPRM.

Regulatory Identifier Number (RIN)

The Department of Transportation assigns a regulation identifier
number (RIN) to each regulatory action listed in the Unified Agenda of
Federal Regulations. The Regulatory Information Service Center
publishes the Unified Agenda in April and October of each year. You may
use the RIN contained in the heading at the beginning of this document
to find this action in the Unified Agenda.

Privacy Act

Anyone is able to search the electronic form of all comments
received into any of our dockets by the name of the individual
submitting the comment (or signing the comment, if submitted on behalf
of an association, business, labor union, etc.). You may review DOT's
complete Privacy Act Statement in the Federal Register published on
April 11, 2000 (Volume

[[Page 9518]]

65, Number 70; Pages 19477-78) or you may visit http://www.regulations.gov.

Issued on: February 26, 2009.
Stephen R. Kratzke,
Associate Administrator for Rulemaking.

Appendix A--Methodology for Assessing Backover Crash Risk by Pedestrian
Location

Monte Carlo simulation was used to calculate a probability-based
risk weighting for each square in a grid of 30-cm squares behind the
vehicle. The grid of 30-cm squares extended 27 m back from the rear
edge of the rear bumper of the vehicle, 6 m forward of the rear
bumper, and 10.5 m to the left and to the right of the longitudinal
centerline of the vehicle, resulting in a total of 7,700 30-cm grid
squares. The probability-based risk weightings for each grid square
were based on the number of pedestrian-vehicle backing crashes
predicted by the simulation for trials for which the pedestrian was
initially (i.e., at the time that the vehicle began to back up) in
the center of one square of the grid of 30-cm squares. For each
Monte Carlo simulation trial, the pedestrian was initially placed in
the center of one square of the grid of 30-cm squares. A total of
1,000,000 Monte Carlo simulation trials were run with the pedestrian
initially in the center of each square. Since the Monte Carlo
simulation used had left-right symmetry, mirroring was used to
increase the effective number of simulation trials to 2,000,000 for
each grid square.
Important assumptions were made about the behavior of the driver
and the pedestrian for this analysis. The vehicle and pedestrian
were assuming to begin moving at the same time and were assumed to
be completely unaware of each other. Therefore, the motions of the
vehicle and pedestrian were totally independent of the each other.
Note that it was possible for the pedestrian to walk or run into the
vehicle. If the impact was with the rear of the vehicle, a back-over
incident was considered to have resulted. If the impact was with the
side or front of the vehicle, the crash was not counted as a backing
crash for the purposes of this analysis.

Vehicle Descriptors

Four descriptors were used to define the simulated vehicle in
this analysis. The width of the vehicle was assumed to be 6.0 feet
for this analysis. The distance that the vehicle backed up during
each backing trial was determined by a random draw from a three-
parameter Weibull probability distribution for distance backed that
was based on data from the ``On-Road Study of Drivers' Use of
Rearview Video Systems'' study.\115\ To simplify the analysis this
simulation assumed that the vehicle backed up at a constant speed
based on a random draw from a three-parameter Weibull probability
distribution also based on NHTSA's research data.\116\
---------------------------------------------------------------------------

\115\ Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and
Ranney, T.A. (2008). On-Road Study of Drivers' Use of Rearview Video
Systems (ORSDURVS). National Highway Traffic Safety Administration,
DOT 811 024.
\116\ Id.
---------------------------------------------------------------------------

Since backing maneuvers frequently involve turning, any backing
trial more than 25 feet long was assumed to possibly include a turn.
To determine whether the vehicle turned to the left, went straight,
or turned to the right during each backing trial, a uniformly
distributed random number was drawn. There was a 40 percent
probability of a left turn, a 40 percent probability of a right
turn, and a 20 percent probability of a no turn. The turn, if there
was one, did not commence until after 25 feet of backing or 30 feet
from the end of the back, whichever was greater. Once turning
commenced the rear bumper of the vehicle traveled around a 20 foot
radius circle. Since the maximum distance in the turn was 30 feet,
the angle which the vehicle turned through ranged from 0 to 85.9
degrees (1.5 radians).

Pedestrian Descriptors

The pedestrian was modeled in the horizontal plane as a circle
of radius 0.375 feet. To simplify the analysis, the pedestrian was
assumed to move at constant speed and direction. The angle of
pedestrian travel was determined by a random draw from a uniform
probability distribution extending from -180.0 to +180.0 degrees.
Walking speed was determined by a random draw from a triangular
probability distribution ranging from 0.0 to 5.0 mph.
To define the position of the pedestrian behind the vehicle,
axes were assigned to the grid. An X axis was set up pointing
straight back along the longitudinal centerline of the vehicle with
its origin at the rear bumper of the vehicle. A Y axis was set up
pointing along the (assumed straight) rear edge of the rear bumper
with its origin at the center of the rear bumper. Positive Y values
were on the driver's side of the vehicle. The pedestrian was always
started at the center of one of the 1-foot grid squares. Therefore,
the initial positions of the pedestrian, in both X and Y, were
always at a half foot mark. All possible initial pedestrian
positions were simulated. Therefore, the initial pedestrian X
positions ranged from 0.5 to 49.5 feet in 1.0-foot increments.
Similarly, the initial pedestrian Y positions ranged from -9.5 to
9.5 feet also in 1.0-foot increments.

Additional Simulation Information

As was previously mentioned, a total of 1,000,000 Monte Carlo
simulation trials were run with the pedestrian initially in the
center of each square. Each trial simulated 60.0 seconds of time
unless the pedestrian collided with the vehicle or the vehicle
completed its movement first. Actual backing events do not last for
60.0 or more seconds. The longest backing event out of the 6,185 in
the ``On-Road Study of Drivers' Use of Rearview Video Systems''
study \117\ data set was 52.8 seconds long. However, for the
simulation, both the backing distance and average backing speed were
determined independently of each other from Weibull probability
distributions. This is actually not correct; statistical analyses of
the ``On-Road Study of Drivers' Use of Rearview Video Systems''
study \118\ data set indicates that for real driving, as backing
distance increases so does average backing speed. However, it was
decided to accept the independence of the backing distance and
average backing speed so as to simplify the simulation. As a result,
1.1 percent of all simulated backing trials had not been completed
after 60.0 seconds of simulation. For the purposes of this analysis
it was decided that the normalization process would probably
adequately account for not otherwise dealing with this issue.
---------------------------------------------------------------------------

\117\ Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and
Ranney, T.A. (2008). On-Road Study of Drivers' Use of Rearview Video
Systems (ORSDURVS). National Highway Traffic Safety Administration,
DOT 811 024.
\118\ Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and
Ranney, T.A. (2008). On-Road Study of Drivers' Use of Rearview Video
Systems (ORSDURVS). National Highway Traffic Safety Administration,
DOT 811 024.
---------------------------------------------------------------------------

A count was made of all trials for which the pedestrian collided
with the rear bumper of the vehicle. If the pedestrian collided
first with either the front or sides of the vehicle, then this was
not counted as a backing collision.
After completion of the simulation for all grid squares, a
normalization of the backing crash counts for each grid square was
performed. The normalization converted each grid square's crash
count into its probability of crash relative to the probability of
crash for the grid squares for which a crash was most likely to
occur. The grid squares for which a crash was most likely to occur
were the two directly behind the bumper in the center of the
vehicle, i.e., the grid squares at (0.5 ft, 0.5 ft) and at (0.5 ft,
-0.5 ft). The relative probability of crash for these two grid
squares was set to 1.0. For all other grid squares, the crash count
was divided by the crash count for grid square (0.5, 0.5). Note that
due to left-right mirroring, the grid squares at (0.5, 0.5) and at
(0.5, -0.5) both had the same crash counts. This resulted in a
probability of crash relative to the probability of crash for the
grid squares at (0.5, 0.5) and at (0.5, -0.5). Since all grid
squares were subjected to the same simulation imperfections, this
first normalization was expected to reduce the impact of these
imperfections of the simulation results.
Figure 1 of this notice summarizes the calculated relative crash
risk for each grid square. Note that the white shaded area does not
have a zero backover risk; it merely has a low (less than 12.5
percent of the maximum) risk.
This analysis shows that the probability of crash decreases
rapidly as the pedestrian's initial location is moved back, further
away, from the rear bumper of the vehicle. There are substantial
side lobes, giving pedestrians a reasonable chance of being hit even
though they were not initially directly behind the vehicle.

Appendix B--Method for On-Road Study of Drivers' Use of Rearview Video
Systems

Drivers' use of rearview video systems was observed during
staged and naturalistic backing maneuvers to determine whether

[[Page 9519]]

drivers look at the RV display during backing and whether use of the
system affects backing behavior.\119\ Thirty-seven test
participants, aged 25 to 60 years, were comprised of twelve drivers
of RV-equipped vehicles, thirteen drivers of vehicles equipped with
an RV system and a rear parking sensor system, and twelve drivers of
vehicles with no backing aid system. All three system conditions
were presented using original equipment configurations of the 2007
Honda Odyssey minivan. All participants had driven and owned a 2007
Honda Odyssey minivan as their primary vehicle for at least 6
months. Participants were not aware that the focus of the study was
on their behavior and performance during backing maneuvers.
---------------------------------------------------------------------------

\119\ Mazzae, E.N., Barickman, F.S., Baldwin, G.H.S., and
Ranney, T.A. (2008). On-Road Study of Drivers' Use of Rearview Video
Systems (ORSDURVS). National Highway Traffic Safety Administration,
DOT 811 024.
---------------------------------------------------------------------------

Participants visited a test lab to have unobtrusive video and
other data recording equipment installed in their personal vehicles,
and for a brief test drive. Participants then drove their vehicles
for a period of 4 weeks in their normal daily activities while
backing maneuvers were recorded. At the end of 4 weeks, participants
returned to the research lab to have the recording equipment
removed. Then, participants took a second test drive, identical to
the first, except that when backing out of the garage bay, an
unexpected 36-inch-tall obstacle consisting of a two-dimensional
photograph of a child appeared behind the vehicle.

Appendix C--Details Regarding Development of a Possible Countermeasure
Application Threshold Based on Rear Blind Zone Area

To begin to investigate what this threshold value might be,
NHTSA plotted the average backing and backover rates versus the
direct-view rear blind zone areas for 28 vehicles, as shown in
Figure C-1. Several options for setting a threshold were examined.
One option could be to choose the natural break point on the plotted
curve at which the slope dramatically increases for crash rate as a
function of direct-view rear blind zone area. This option results in
vehicles with the poorest rear visibilities that contribute
disproportionately to backover crashes being affected. One
observation with this option is that the worst offenders for rear
visibility would be captured, but a large percentage of overall
backover crashes would not be addressed, such as those involving
small pickups.
[GRAPHIC] [TIFF OMITTED] TP04MR09.014

Figure C-1. Backing and Backover Crash Rates as a Function of Rear
Blind Zone AreaAppendix D--Results for Analysis of Correlation Between
Rear Blind Zone Area Measurement Field Size and Backing Crashes

To support the determination of the dimensions of the rear
visibility measurement field, NHTSA's measured rear blind zone area
data for a variety of vehicles were compared with backing crashes
for those vehicles. Data analysis was performed to assess the
correlation between vehicles' rear blind zone areas measured using a
50th percentile male driver and backing crash data for 21
vehicles.\120\ Complete results of this analysis for a portion of
the field sizes assessed are summarized in Table D-1.
---------------------------------------------------------------------------

\120\ Mazzae, E.N., Light Vehicle Rear Visibility Assessment,
DOT HS 810 909, September 2008. NHTSA's visual target for this test
was a traffic cone with a reflector atop; its height is
representative of a 1-year-old child.

[[Page 9520]]

Table D-1--Correlation Between Human-Based Rear Blind Zone Area Measured
Over Various Field Sizes and Backing Crashes
[Sorted by correlation coefficient]
------------------------------------------------------------------------
Probability
Measurement field dimensions (width by Correlation occurred by
length) coefficient chance
------------------------------------------------------------------------
50W x 10L............................... 0.60117 0.0039
40W x 10L............................... 0.60117 0.0039
30W x 10L............................... 0.58233 0.0056
30W x 50L............................... 0.55212 0.0095
40W x 40L............................... 0.54681 0.0103
30W x 40L............................... 0.53635 0.0122
50W x 40L............................... 0.53113 0.0132
20W x 40L*.............................. 0.52621 0.0143
50W x 50L**............................. 0.52375 0.0148
20W x 50L............................... 0.52367 0.0148
40W x 30L............................... 0.52341 0.0149
50W x 60L............................... 0.51360 0.0172
30W x 30L............................... 0.51227 0.0176
60W x 50L............................... 0.51891 0.0159
50W x 30L............................... 0.50641 0.0192
60W x 60L............................... 0.50403 0.0198
40W x 20L............................... 0.48513 0.0258
20W x 30L............................... 0.48117 0.0272
50W x 20L............................... 0.47920 0.0280
70W x 70L............................... 0.47331 0.0302
70W x 80L............................... 0.45159 0.0399
70W x 90L............................... 0.43665 0.0478
20W x 20L............................... 0.39522 0.0762
10W x 40L............................... 0.35315 0.1163
10W x 10L............................... 0.27903 0.2206
------------------------------------------------------------------------
* This measurement field size was indicated by pedestrian backover crash
risk simulation as encompassing pedestrian locations at which risk of
a backing crash was 20 percent or higher.
** Blind zone area measured over a field this size was found by
preliminary analysis of laser-based measurement data to be well
correlated with backing crashes.

[FR Doc. E9-4500 Filed 2-27-09; 11:15 am]
BILLING CODE 4910-59-P