What is the function of a retarder applied in buses?
Show the correct answer
Correct answer
B. It offers the possibility of an alternative method of braking.
Explanation
In the photo you can see a lever by the steering wheel of a bus with the symbol of the retarder. The retarder gives an alternative way of braking - answer B.
The Road Traffic Act requires a vehicle to allow reliable use of the braking controls. A retarder is an additional brake, usually hydraulic or electromagnetic, which slows the bus down without using the service brakes. You use it especially on long descents and when losing speed before a bend, so that the linings and discs do not overheat and stay cool in case of sudden braking. A retarder does not help with accelerating (answer A) - on the contrary, it creates resistance. Nor does it protect against skidding (answer C); on a slippery surface, heavy use of the retarder can even make the drive axle skid, so you use it gently.
Legal basis: Art. 66 para. 1 point 5 of the Road Traffic Act (Prawo o ruchu drogowym)