Using Air Brakes Safely
Safe use of air brakes starts with understanding that air brakes are not instantaneous. There is a slight lag between pressing the pedal and the brakes applying, so you must plan ahead and increase following distance. Braking distance is longer than with hydraulic brakes, especially when heavily loaded.
Use progressive braking: apply steady, increasing pressure rather than pumping. Pumping wastes air and can reduce available pressure. On long downgrades, use a low gear and engine braking to control speed, applying the brakes in short applications rather than riding them continuously, which can overheat the brakes and cause fade.
Speed management is critical. Enter curves and downgrades at a safe speed, and avoid harsh braking on slippery surfaces. Remember that spring brakes are for parking and emergencies, not for normal stopping. The parking brake should be set whenever you leave the vehicle.
A common trap is thinking you can pump the brakes to build pressure; pumping actually uses up air. Another trap is riding the brakes down a long hill, which can cause overheating and loss of braking. Questions often test the idea of using a lower gear and controlled braking on downgrades.
Rule of thumb: look ahead, keep space, brake progressively, and use gears, not brakes alone, to control speed on long downgrades.