When is it obligatory to operate the vehicle speed retarders?

1. When driving in a road section before which a “hairpin curve” sign is placed.
2. When driving in a road section before which a “danger of sliding” sign is placed.
3. Correct answer: When driving in a road section where a “dangerous descent” sign is placed.
4. When driving in a road section before which a “sharp curve” sign is placed.

WhyThe speed retarder is used on the road section after a dangerous descent sign. Bends and slippery roads are not the trigger.