Commercial Vehicle Safety Inspections, Brakes and Emergency Procedures
What this domain tests
This domain tests inspection responsibilities, brake condition, and emergency response. Ontario expects a driver to know when a vehicle is out of service, how to check brake adjustment, and what to do when brakes fade or a tire fails.
Inspection and brake condition
- Complete and record the daily inspection; report defects and do not operate with a major defect.
- Know that commercial vehicles also require periodic annual inspections and that CVOR records affect the operator’s standing.
- Check pushrod travel and slack adjuster operation; a brake that is out of adjustment may not apply full force.
- Understand brake fade: overheating reduces friction, so use gears and engine braking on long downgrades instead of riding the pedal.
Emergency procedure
- For a tire blowout, hold the wheel firmly, ease off the throttle, and avoid hard braking until control is regained.
- For a brake failure, downshift, use engine braking, apply the trailer brake or parking brake gradually, and look for a runaway lane.
- For a fire, stop, shut off the engine, evacuate, and use the extinguisher from upwind.
Worked example: A loaded tractor-trailer’s service brakes fade on a long descent. Pumping the pedal repeatedly will not restore friction and can exhaust air pressure. The correct response is to select a lower gear, use the engine brake, apply the parking brake in controlled stages, and stop at the first safe pullout.
Traps: assuming ABS shortens stopping distance; applying a spring brake at highway speed and locking the wheels; and continuing after a low-air warning because the vehicle still rolls. A low-air warning is a stop-now defect.