Vehicle knowledge: bus construction, systems and inspection (Kjøretøyteknikk)
Vehicle knowledge: bus construction, systems and inspection (Kjøretøyteknikk)
This domain tests the bus as a machine: air-brake system, doors and interlocks, steering and suspension, tyres, lights, warning systems and the periodic inspection regime.
Core systems
- Most Category D buses use air brakes. The compressor charges reservoirs; a low-pressure warning and gauge tell you when pressure is insufficient. Drain condensate daily from the reservoirs. Spring brakes apply automatically when pressure falls, so the bus cannot be driven with a serious air leak.
- Know ABS/EBS and ESP functions. ABS prevents wheel lock; ESP helps against skidding. Neither shortens the physical braking distance on ice.
- A retarder or engine brake saves the service brakes on long descents. It does not replace the parking brake.
- Passenger doors have an interlock: the bus should not be able to pull away with a door open. Know the emergency release and the door-brake override, and never defeat the interlock.
- Daily walk-around: tyres and tread, wheel nuts, lights, mirrors, windscreen, wipers, washers, fuel/AdBlue, fire extinguisher, first-aid kit, emergency exits, ramps and wheelchair restraints.
- Buses are subject to periodic vehicle inspection at least annually once in service; the first inspection is due within two years of registration. An overdue inspection or a safety defect grounds the bus.
Worked example
The low-pressure warning sounds as you start. The gauge shows 4 bar and falling. Do not drive. The spring brakes may be partially applied and brake performance is unpredictable. Switch off, check for a visible leak or a failed compressor belt only if safe, and report the defect. A bus with insufficient air pressure is not roadworthy.
Traps
Treating the retarder as a parking brake; ignoring a slow pressure drop; driving with a door interlock warning; and assuming ABS will stop you on ice. Check the inspection record and the daily defect log.