[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: 49CFR393.41]

[Page 1063-1064]
 
                        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. 393.41  Parking brake system.

    (a) Every commercial motor vehicle manufactured on and after March 
7, 1990, except an agricultural commodity trailer, converter dolly, 
heavy hauler or pulpwood trailer, shall at all times be equipped with a 
parking brake system adequate to hold the vehicle or combination under 
any condition of loading as required by FMVSS 571.121. An agricultural 
commodity trailer, heavy hauler or pulpwood trailer shall carry 
sufficient chocking blocks to prevent movement when parked.
    (b) The parking brake system shall at all times be capable of being 
applied in conformance with the requirements of paragraph (a) of the 
section by either the driver's muscular effort, or by spring action, or 
by other energy, provided, that if such other energy is depended on for 
application of the parking brake, then an accumulation of such energy 
shall be isolated from any common source and used exclusively for the 
operation of the parking brake.

[[Page 1064]]

    (c) The parking brake system shall be held in the applied position 
by energy other than fluid pressure, air pressure, or electric energy. 
The parking brake system shall be such that it cannot be released unless 
adequate energy is available upon release of the parking brake to make 
immediate further application with the required effectiveness.

[34 FR 15418, Oct. 3, 1969, as amended at 53 FR 49398, Dec. 7, 1988]