In which of the following situations can the ABS of a bus be ineffective when braking?
Show the correct answer
Correct answer
B. When driving on uneven road surfaces.
Explanation
The question is about the situation in which ABS may be ineffective when braking a bus. This happens when driving over many bumps in the road - answer B.
The Road Traffic Act requires a vehicle to ensure reliable use of the brakes, but no system will change the laws of physics. ABS judges whether a wheel is locking on the basis of its rotational speed. On bumps, the wheels bounce and lose contact with the road surface for a moment, so the sensors read this as locking, and the system reduces the braking force - the stopping distance becomes longer. In the rain (answer A) ABS works, and that is exactly when it helps you keep steering control. On a dry, even surface (answer C) braking is most effective, and ABS works properly. So on a road full of potholes you drive more slowly and brake with a bigger safety margin.
Legal basis: Art. 66 para. 1 point 5 of the Road Traffic Act (Prawo o ruchu drogowym)