On which of the following commercial vehicles and work vehicles is it obligatory to have a compression brake (retarder)?

1. On all of them, regardless of weight.
2. Correct answer: On a vehicle weighing at 8,000 kg or more.
3. On a vehicle weighing at least 12,000 kg.
4. On a vehicle weighing weighing 4,500 kg or more.

WhyAn engine brake is needed on commercial and work vehicles of 8,000 kg or more. It helps hold the vehicle back on long descents.