You're driving a vehicle equipped with a dual air brake system. The low air pressure warning signal comes on, but one system still has normal pressure. What should you do?
- Slow down and test the brakes.
- Slow down and drive to the nearest garage.
- Continue your trip as usual.
- Stop your vehicle as soon as possible. ✓
Answer: D. Stop your vehicle as soon as possible.
Stop your vehicle as soon as possible; when the low-air pressure warning signal comes on, the handbook says to pull over and stop rather than keep driving.
Why this is the answer
The handbook treats the low-air warning as a signal to stop right away and find out why air pressure dropped. It says that if the warning activates, you should stop immediately and not continue until a repair is made. Another passage tells you to pull over and stop and not go further until you know the air brake system is safe. The remaining air may be enough for a controlled stop if you act promptly, so the answer is to stop, not to keep the trip going.
Why the other answers are wrong
- A. Slow down and test the brakes. — Slowing down and testing the brakes is not enough, because the handbook says to stop and find the cause of the air loss, not to continue after a brake check.
- B. Slow down and drive to the nearest garage. — Slowing down and heading for the nearest garage still keeps you driving with a low-air warning, while the handbook says to pull over and stop until you know the system is safe.
- C. Continue your trip as usual. — Continuing as usual ignores the warning, and the handbook says not to go further until the cause is found and the air brake system is safe.
Remember it
When the low-air warning shows up, stop first and diagnose second.
Official handbook: ICBC Driving Commercial Vehicles, 8 Air brakes – Parking brakes, p. 160