Question Truck tractors with air brakes built on or after March 1, 1997 must be equipped with: Answers ABS. A flag. White warning lamps. GPS. Explanation Truck tractors with air brakes built on or after March 1, 1997 must be equipped with an Anti-Lock Braking System (ABS). Take a FREE Practice Test Now This questions appears in the following tests: Nebraska Knowledge Test Class A , Arkansas Knowledge Test Class B , Indiana Knowledge Test Class B ,