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CDL · Antilock Brakes

Are converter dollies required to have antilock brakes?

Correct answer

Converter dollies manufactured on or after March 1, 1998 are required to have ABS

  1. A Never
  2. B Converter dollies manufactured on or after March 1, 1998 are required to have ABS
  3. C Only for triples
  4. D Only for combinations over a certain weight

Why this is the answer

Federal regulations require ABS on air-braked converter dollies manufactured on or after March 1, 1998, matching the requirement for trailers. ABS on the dolly is important because the dolly's wheels are part of the braking system; locked dolly wheels can contribute to jackknife or trailer swing during heavy braking. An ABS warning light on the dolly indicates a malfunction that should be addressed at the next opportunity. Dollies made before March 1998 are not required to have ABS but may have been retrofitted. The full combination (tractor + lead trailer + dolly + rear trailer) should ideally have ABS on every unit to deliver the full safety benefit during emergency braking.
Source: FMCSA CDL Manual 7.4.1 Dolly ABS

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