[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: 49CFR393.40]

[Page 1063]
 
                        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. 393.40  Required brake systems.


    (a) General. A bus, truck, truck tractor, or a combination of motor 
vehicles must have brakes adequate to control the movement of, and to 
stop and hold, the vehicle or combination of vehicles.
    (b) Specific systems required. (1) A bus, truck, truck tractor, or 
combination of motor vehicles must have--
    (i) A service brake system that conforms to the requirements of 
Sec. 393.52; and
    (ii) A parking brake system that conforms to the requirements of 
Sec. 393.41.
    (2) A bus, truck, truck tractor, or a combination of motor vehicles 
manufactured on or after July 1, 1973, must have an emergency brake 
system that conforms to the requirements of Sec. 393.52(b) and consists 
of either--
    (i) Emergency features of the service brake system; or
    (ii) A system separate from the service brake system.

A control by which the driver applies the emergency brake system must be 
located so that the driver can readily operate it when he/she is 
properly restrained by any seat belt assembly provided for his/her use. 
The control for applying the emergency brake system may be combined with 
either the control for applying the service brake system or the control 
for applying the parking brake system. However, all three controls may 
not be combined.
    (c) Interconnected systems. (1) If the brake systems specified in 
paragraph (b) of this section are interconnected in any way, they must 
be designed, constructed, and maintained so that, upon the failure of 
any part of the operating mechanism of one or more of the systems 
(except the service brake actuation pedal or valve)--
    (i) The vehicle will have operative brakes; and
    (ii) In the case of a vehicle manufactured on or after July 1, 1973, 
the vehicle will have operative brakes capable of performing as 
specified in Sec. 393.52(b).
    (2) A motor vehicle to which the emergency brake system requirements 
of Federal Motor Vehicle Safety Standard No. 105 (Sec. 571.105 of this 
title) applied at the time of its manufacture conforms to the 
requirements of paragraph (c)(1) of this section if--
    (i) It is maintained in conformity with the emergency brake 
requirements of Standard No. 105 in effect on the date of its 
manufacture; and
    (ii) It is capable of performing as specified in Sec. 393.52(b), 
except upon structural failure of its brake master cylinder body or 
effectiveness indicator body.
    (3) A bus conforms to the requirements of paragraph (c)(1) of this 
section if it meets the requirements of Sec. 393.44 and is capable of 
performing as specified in Sec. 393.52(b).

[36 FR 20297, Oct. 20, 1971, as amended at 37 FR 5251, Mar. 11, 1972]