[Code of Federal Regulations]
[Title 49, Volume 5]
[Revised as of October 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR325.93]

[Page 18]
 
                        TITLE 49--TRANSPORTATION
 
                      DEPARTMENT OF TRANSPORTATION
 
PART 325_COMPLIANCE WITH INTERSTATE MOTOR CARRIER NOISE EMISSION 
STANDARDS--Table of Contents
 
                   Subpart G_Exhaust Systems and Tires
 
Sec.  325.93  Tires.

    (a) Except as provided in paragraph (b) of this section, a motor 
vehicle does not conform to the visual tire inspection requirements, 40 
CFR 202.23, of the Interstate Motor Carrier Noise Emissions Standards, 
if inspection of any tire on which the vehicle is operating discloses 
that the tire has a tread pattern composed primarily of cavities in the 
tread (excluding sipes and local chunking) which are not vented by 
grooves to the tire shoulder or circumferentially to each other around 
the tire.
    (b) Paragraph (a) of this section does not apply to a motor vehicle 
operated on a tire having a tread pattern of the type specified in that 
paragraph, if the motor carrier who operates the motor vehicle 
demonstrates to the satisfaction of the Administrator or his/her 
designee that either--
    (1) The tire did not have that type of tread pattern when it was 
originally manufactured or newly remanufactured; or
    (2) The motor vehicle generates a maximum sound level reading of 90 
dB(A) or less when measured at a standard test site for highway 
operations at a distance of 15.3 meters (50 feet) and under the 
following conditions:
    (i) The measurement must be made at a time and place and under 
conditions specified by the Administrator or his/her designee.
    (ii) The motor vehicle must be operated on the same tires that were 
installed on it when the inspection specified in paragraph (a) of this 
section occurred.
    (iii) The motor vehicle must be operated on a highway having a 
posted speed limit of more than 56.3 kph (35 mph).
    (iv) The sound level measurement must be made while the motor 
vehicle is operating at the posted speed limit.

[40 FR 42437, Sept. 12, 1975, as amended at 60 FR 38743, July 28, 1995]

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