A heavy vehicle operator driving a truck without an antilock braking system (ABS) must execute an emergency stab stop to avoid a sudden road hazard. Arrange the operational actions in the correct chronological sequence required to perform this emergency braking technique.
- 1Apply the service brakes with full pedal pressure until the wheels lock up.
- 2Release the brake pedal fully as soon as the wheels lock up.
- 3Wait up to one-half second for the wheels to begin rolling again and regain directional stability.
- 4Reapply the service brakes with full pedal force once all wheels are rolling freely.
- 5Repeat the cycle of applying, releasing, and reapplying the brakes until the vehicle comes to a complete halt.
Answer
The correct sequence begins with applying full brake pressure until wheel lockup, immediately releasing the brake pedal, waiting up to one-half second for the wheels to regain rolling momentum, reapplying full brake pressure once rolling, and repeating the cycle until fully stopped.
In commercial vehicles without ABS, the stab braking technique requires applying the service brakes fully until lockup occurs, releasing the pedal completely, allowing up to one-half second for all wheels to resume rolling and regain steering control, reapplying full brake force once rolling, and repeating the sequence until stopped. Reapplying the brakes before the wheels roll prevents the vehicle from straightening out.
Step-by-Step Solution
Key Concept
Emergency stab braking procedure on non-ABS commercial motor vehicles
Estimated Time:1m 30s