Question Some air brake systems use alcohol: Answers To reduce the risk of ice forming in air brake valves. To make the compressor run more efficiently. To lubricate parts of the braking system. To reduce the risk of rust forming on air brake valves. Explanation Some air brake systems contain an alcohol evaporator. This device introduces alcohol into the braking system to inhibit the formation of ice. This questions appears in the following tests: Colorado Class A Knowledge Test District Of Columbia Air Brakes Georgia Class B Knowledge Test Georgia Air Brakes New Hampshire Class B Knowledge Test North Carolina Class B Knowledge Test Pennsylvania Class A Knowledge Test Wisconsin Air Brakes