[Code of Federal Regulations]
[Title 49, Volume 4]
[Revised as of October 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR393.48]

[Page 1067-1068]
 
                        TITLE 49--TRANSPORTATION
 
        CHAPTER III--FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION,
                      DEPARTMENT OF TRANSPORTATION
 
PART 393--PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION--Table of Contents
 
                            Subpart C--Brakes
 
Sec. 393.48  Brakes to be operative.

    (a) General rule. Except as provided in paragraphs (b) and (c) of 
this section, all brakes with which a motor vehicle is equipped must at 
all times be capable of operating.
    (b) Devices to reduce or remove front-wheel braking effort. A motor 
vehicle may be equipped with a device to reduce the braking effort upon 
its front wheels or, in the case of a three-axle truck or truck tractor 
manufactured before March 1, 1975, to remove the braking effort upon its 
front wheels, if that device conforms to, and is used in compliance 
with, the rules in paragraph (b) (1) or (2) of this section.
    (1) Manually operated devices. A manually operated device to reduce 
or remove the front-wheel braking effort must not be--
    (i) Installed in a motor vehicle other than a bus, truck, or truck 
tractor; or
    (ii) Installed in a bus, truck, or truck tractor manufactured after 
February 28, 1975; or

[[Page 1068]]

    (iii) Used in the reduced mode except when the vehicle is operating 
under adverse conditions such as wet, snowy, or icy roads.
    (2) Automatic devices. An automatic device to reduce the front-wheel 
braking effort by up to 50 percent of the normal braking force, 
regardless of whether or not antilock system failure has occurred on any 
axle, must not--
    (i) Be operable by the driver except upon application of the control 
that activates the braking system; and
    (ii) Be operable when the pressure that transmits brake control 
application force exceeds--
    (A) 85 psig on air-mechanical braking systems; or
    (B) 85 percent of the maximum system pressure in the case of 
vehicles utilizing other than compressed air.
    (c) Towed vehicle. Paragraph (a) of this section does not apply to--
    (1) A disabled vehicle being towed; or
    (2) A vehicle being towed in a driveaway-towaway operation which is 
exempt from the general rule of Sec. 393.42 under paragraph (b) of that 
section.

(Sec. 204 of the Interstate Commerce Act, as amended (49 U.S.C. 304); 
sec. 6 of the Department of Transportation Act (49 U.S.C. 1655), and the 
delegations of authority by the Secretary of Transportation and the 
Federal Highway Administrator at 49 CFR 1.48 and 301.60, respectively)

[39 FR 26907, July 24, 1974, as amended at 41 FR 29130, July 15, 1976; 
41 FR 53031, Dec. 3, 1976]