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Antilock Brake Systems

Antilock Brake Systems on combination vehicles fall under the general operating-practices knowledge area, 49 CFR 383.111(c)(3)(ii). The ABS equipment mandate for trailers is directly codified at 49 CFR 393.55(c)(2).

Practice Antilock Brake Systems

4 Questions

  1. Under 49 CFR 393.55, which combination-vehicle components must have antilock brake systems (ABS) if manufactured on or after March 1, 1998?
  2. A trailer was built before ABS became mandatory, and it is not clear from the outside whether it has ABS installed. According to the manual, how can a driver check?
  3. You are driving a tractor-trailer combination and are not sure whether the trailer has ABS. How should you brake?
  4. A combination vehicle has ABS on the trailer only. While braking hard, the driver begins to lose steering control and feels the start of a tractor jackknife. What should the driver do?