Question You must have an air brake endorsement: Answers To use a vehicle with air brakes. To drive any truck with a trailer. To transport hazardous materials. Explanation You must take an air brakes knowledge test to become licensed to operate a vehicle that is equipped with air brakes, including an air over hydraulic braking system. Take a FREE Practice Test Now This questions appears in the following tests: Oklahoma Knowledge Test Class A , Utah Knowledge Test Class A , Connecticut Knowledge Test Class B , Idaho Knowledge Test Class B , South Dakota Knowledge Test Class B , Wyoming Knowledge Test Class B , Virginia Air Brakes ,