What is the function of a vehicle’s retarder?
- Serve as an alternative to the service brakes (foot brake), in order to stop the vehicle when it is under imminent danger during an emergency.
- Assist the parking brake (hand brake) while parking on a steep descent.
- Balance the engine’s function and regulate the motor rotations,
- Correct answer: To reduce the vehicle speed, without using the vehicle’s braking system, e.g. during a long descent.
Why this is the answer
The correct answer in the official bank: To reduce the vehicle speed, without using the vehicle’s braking system, e.g. during a long descent.
A retarder is an extra slowing system on heavy vehicles that works separately from the braking system. It keeps speed under control while driving, especially on long descents, so the service brakes do not overheat and lose their effectiveness. It does not replace the foot brake for emergency stops and is not used to hold the vehicle when parked.