CDL Air Brakes TestUsing Air BrakesHard
A driver is operating a commercial vehicle on a very slippery road and needs to slow down. To maintain steering control and prevent a skid, which braking technique should be primarily used if the vehicle does NOT have ABS?
- AUse the stab braking method by applying firm pressure, then releasing completely.
- BShift to neutral and apply emergency brakes intermittently.
- CPump the brake pedal rapidly and continuously.
- DApply continuous, light brake pressure.
Show answer & explanationAnswer & explanation
Correct answer: A. Use the stab braking method by applying firm pressure, then releasing completely.
Stab braking involves applying the brakes firmly until the wheels just begin to lock up, then releasing completely until they roll freely, and repeating. This allows for maximum braking on slippery surfaces without losing steering control, especially without ABS.
Why the other options are wrong
- B. Shifting to neutral removes engine braking, and using emergency brakes can easily cause a full skid and loss of control, which is extremely dangerous.
- C. Rapid, continuous pumping is less effective than stab braking; it doesn't allow for full brake application and release cycles necessary to regain traction.
- D. Continuous light pressure on slippery roads may still lead to wheel lock-up and loss of control without the ability to release and regain traction.
Stab Braking (Non-ABS, Slippery)
A braking technique for non-ABS vehicles on slippery surfaces, where the driver applies firm brake pressure, releases completely when wheels are about to lock, and then reapplies, to maximize braking while maintaining steering.
- For vehicles without ABS.
- Used on slippery surfaces.
- Apply firm, release completely, reapply.
- Prevents sustained wheel lock-up.
Memory trick: Slippery Road, No ABS? 'Stab and Steer, My Dear!'