When is it obligatory to operate the vehicle’s different types of decelerators or retarders ?
- When driving on a road section before which a “sharp curve” sign is placed.
- When driving on a road section before which a “danger of slipping” sign is placed.
- When driving on a road section before which a “hairpin curve” sign is placed.
- Correct answer: When driving on a road section before which a “dangerous descent” sign is placed.
Why this is the answer
The correct answer in the official bank: When driving on a road section before which a “dangerous descent” sign is placed.
Decelerators and retarders, such as the engine brake, exhaust brake or hydraulic retarder, must be used on a road section marked with a dangerous descent sign. On a long downhill, relying only on the service brakes overheats them and can cause brake fade or failure. Retarders hold a steady speed and keep the regular brakes cool and ready for stopping. Curves require slowing down beforehand, but this specific obligation applies to descents.