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  • § 393.11
    Lamps and reflective devices.
  • § 393.17
    Lamps and reflectors—combinations in driveaway-towaway operation.
  • § 393.24
    Requirements for head lamps, auxiliary driving lamps and front fog lamps.
  • § 393.25
    Requirements for lamps other than head lamps.
  • § 393.28
    Wiring systems.
  • § 393.40
    Required brake systems.
  • § 393.41
    Parking brake system.
  • § 393.42
    Brakes required on all wheels.
  • § 393.43
    Breakaway and emergency braking.
  • § 393.44
    Front brake lines, protection.
  • § 393.48
    Brakes to be operative.
  • § 393.51
    Warning signals, air pressure and vacuum gauges.
  • § 393.52
    Brake performance.
  • § 393.60
    Glazing in specified openings.
  • § 393.61
    Truck and truck tractor window construction.
  • § 393.62
    Emergency exits for buses.
  • § 393.65
    All fuel systems.
  • § 393.67
    Liquid fuel tanks.
  • § 393.70
    Coupling devices and towing methods, except for driveaway-towaway operations.
  • § 393.71
    Coupling devices and towing methods, driveaway-towaway operations.
  • § 393.75
    Tires.
  • § 393.76
    Sleeper berths.
  • § 393.81
    Horn.
  • § 393.82
    Speedometer.
  • § 393.83
    Exhaust systems.
  • § 393.87
    Warning flags on projecting loads.
  • § 393.88
    Television receivers.
  • § 393.89
    Buses, driveshaft protection.
  • § 393.92
  • § 393.93
    Seats, seat belt assemblies, and seat belt assembly anchorages.
  • § 393.100
    Which types of commercial motor vehicles are subject to the cargo securement standards of this subpart, and what general requirements apply?
  • § 393.102
    What are the minimum performance criteria for cargo securement devices and systems?
  • § 393.106
    What are the general requirements for securing articles of cargo?
  • § 393.201
    Frames.

Part 393

Section § 393.48: Brakes to be operative.

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The regulations text of the section can be found on the eCFR website. To view the regulations text, use the link below. For assistance, please send an email to FMCSA.Webmaster@dot.gov.
View regulations for Part 393

Question 1: If a Commercial Motor Vehicle CMV manufactured on or after July 25, 1980 (see §393.42) has brake components on the front axle, and the brakes are not operable, does the vehicle comply with §393.48?

Guidance: No.

Question 2: If a truck or truck tractor manufactured prior to July 25, 1980, and having 3 or more axles, has inoperable brakes on the front axle or some of the brake components are missing, would the vehicle be in violation of §393.48?

Guidance: Yes. §393.48(a) requires that all brakes with which the vehicle is equipped must be operable at all times. Although §393.42(b)(1) provides an exception to the requirement for brakes on all wheels for trucks and truck tractors with 3 or more axles and manufactured prior to July 25, 1980, the exception does not affect the applicability of §393.48 for those cases in which the vehicle is equipped with inoperable front wheel brakes or only has certain portions of the front wheel brake system (e.g., shoes, linings, chambers, hoses) in place.

Question 3: Are the brakes on a vehicle towed in a driveaway-towaway operation or towed disabled vehicle required to be operable at all times?

Guidance: §393.48(c) provides an exception to the requirement that brakes be operable at all times. This exception covers disabled vehicles being towed and vehicles towed in a driveaway-towaway operation.

The driveaway-towaway exception in §393.48(c) is contingent upon the conditions outlined in §393.42(b)(2). Towed vehicles must have brakes as may be necessary to ensure compliance with the performance requirements of §393.52. A motor vehicle towed by means of a tow-bar when any other vehicle is full-mounted on the towed vehicle, or any combination of motor vehicles utilizing 3 or more saddle-mounts, would not be covered under the exception found at §393.48(c).

With regard to the disabled-vehicle provision of §393.48(c)(1), the combination vehicle would have to meet the applicable performance requirements of §393.52.


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