Do you currently have car insurance? Insurance is mandatory to drive in California Yes I have insurance. But please show me your best quotes. No, please help me find the best insurance. Question Most heavy-duty vehicles use ____ air brake systems. Answers Single Dual Triple Quad Explanation The majority of heavy-duty vehicles are equipped with dual air brake systems. Take a FREE Practice Test Now This questions appears in the following tests: Kansas Air Brakes , Maryland Air Brakes , Nebraska Air Brakes , Texas Air Brakes ,