Which of the following driving techniques is the best when driving a loaded lorry downhill?
Show the correct answer
Correct answer
A. Driving downhill with an appropriately chosen gear and using the retarder.
Explanation
The question is about driving downhill in a loaded lorry. It is best to drive down in a suitably chosen gear and using the retarder - answer A.
The Road Traffic Act requires you to drive at a speed that keeps the vehicle under control, taking into account the shape of the land and the load, and to brake in a way that does not create danger. The retarder and the exhaust brake (engine brake) slow the vehicle down without using the service brake, so the service brake stays cool and ready for sudden braking. A high gear and braking only with the service brake (answer B) lead to overheating of the linings and the discs or drums, and overheated brakes lose their effectiveness. Going downhill in neutral (answer C) is even more dangerous: the engine does not brake at all, and the vehicle picks up speed. You choose the gear before the descent, usually the same gear in which you would be able to drive up this hill.
Legal basis: Art. 19 para. 1 and para. 2 point 2 of the Road Traffic Act (Prawo o ruchu drogowym)