Colorado CDL Practice Test 2025 – Complete Exam Prep

Retarders are devices used in vehicles, particularly heavy trucks, to help slow down the vehicle and reduce brake wear. They provide an additional method of deceleration beyond the conventional braking system, allowing the driver to maintain better control of the vehicle, especially on downhill slopes. By using retarders, drivers can manage speed effectively without having to frequently apply the brakes, which minimizes wear on the braking components. This is especially beneficial during long descents, where repeated use of brakes can lead to overheating and diminished braking effectiveness. Therefore, the primary purpose of retarders is to safely slow a vehicle while simultaneously extending the life of the braking system.