Most heavy-duty vehicles use: Question Most heavy-duty vehicles use: Answers Mono air brake systems. Dual air brake systems. Triple air brake systems. Quadruple air brake systems. Explanation Most heavy-duty vehicles use dual air brake systems. A dual system has two separate air brake systems with a single set of controls. This questions appears in the following tests: Arkansas Class B Knowledge Test Connecticut Class B Knowledge Test Massachusetts Double Massachusetts Air Brakes New Jersey Class A Knowledge Test New Jersey Air Brakes New Jersey Air Brakes North Dakota Air Brakes Utah Class B Knowledge Test West Virginia Air Brakes
