In what types of buses is it obligatory to have a speed retarder?
- Every bus in which a techograph was installed.
- Correct answer: Buses with a minimum all up weight of 10,000 kg.
- Every bus in which a retarder was installed during its manufacturing process.
- Every bus that is permitted to carry more than 20 passengers.
Why this is the answer
The correct answer in the official bank: Buses with a minimum all up weight of 10,000 kg.
The requirement for a speed retarder depends on the bus's total weight: buses with an all up weight of 10,000 kg or more must have one. A retarder is an auxiliary braking system that slows a heavy vehicle without using the service brakes, preventing them from overheating and fading on long descents. Passenger capacity or having a tachograph is not what triggers this obligation.