Question An Anti-Lock Braking System (ABS): Answers Is not available for most trucks. Is not helpful in most situations. Is required on newer trucks. Explanation Beginning between 1997 and 1999, most commercial vehicles, trailers, and dollies are required to be equipped with ABS. Take a FREE Practice Test Now This questions appears in the following tests: Idaho Knowledge Test Class A , Maryland Knowledge Test Class A , Wyoming Knowledge Test Class A , Alaska Knowledge Test Class B , South Carolina Knowledge Test Class B , Oklahoma Passenger ,