[Code of Federal Regulations]

[Title 49, Volume 5]

[Revised as of October 1, 2005]

From the U.S. Government Printing Office via GPO Access

[CITE: 49CFR393.41]



[Page 396-397]

 

                        TITLE 49--TRANSPORTATION

 

                      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) Hydraulic-braked vehicles manufactured on or after September 2, 

1983. Each truck and bus (other than a school bus) with a GVWR of 4,536 

kg (10,000 pounds) or less which is subject to this part and school 

buses with a GVWR greater than 4,536 kg (10,000 pounds) shall be 

equipped with a parking brake system as required by FMVSS No. 571.105 

(S5.2) in effect at the time of manufacture. The parking brake shall be 

capable of holding the vehicle or combination of vehicles stationary 

under any condition of loading in which it is found on a public road 

(free of ice and snow). Hydraulic-braked vehicles which were not subject 

to the parking brake requirements of FMVSS No. 571.105 (S5.2) must be 

equipped with a parking brake system that meets the requirements of 

paragraph (c) of this section.

    (b) Air-braked power units manufactured on or after March 1, 1975, 

and air-



[[Page 397]]



braked trailers manufactured on or after January 1, 1975.

    Each air-braked bus, truck and truck tractor manufactured on and 

after March 1, 1975, and each air-braked trailer except an agricultural 

commodity trailer, converter dolly, heavy hauler trailer or pulpwood 

trailer, shall be equipped with a parking brake system as required by 

FMVSS No. 121 (S5.6) in effect at the time of manufacture. The parking 

brake shall be capable of holding the vehicle or combination of vehicles 

stationary under any condition of loading in which it is found on a 

public road (free of ice and snow). An agricultural commodity trailer, 

heavy hauler or pulpwood trailer shall carry sufficient chocking blocks 

to prevent movement when parked.

    (c) Vehicles not subject to FMVSS Nos. 105 and 121 on the date of 

manufacture. (1) Each singly driven motor vehicle not subject to parking 

brake requirements of FMVSS Nos. 105 or 121 at the time of manufacturer, 

and every combination of motor vehicles must be equipped with a parking 

brake system adequate to hold the vehicle or combination on any grade on 

which it is operated, under any condition of loading in which it is 

found on a public road (free of ice and snow).

    (2) The parking brake system shall, at all times, be capable of 

being applied by either the driver's muscular effort or by spring 

action. If other energy is used to apply the parking brake, there must 

be an accumulation of that energy isolated from any common source and 

used exclusively for the operation of the parking brake.

    Exception: This paragraph shall not be applicable to air-applied, 

mechanically-held parking brake systems which meet the parking brake 

requirements of FMVSS No. 121 (S5.6).

    (3) 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 not be capable of being released unless 

adequate energy is available to immediately reapply the parking brake 

with the required effectiveness.



[70 FR 48048, Aug. 15, 2005]