CDL General Knowledge TestCombination Vehicles (if applicable)Hard
You are driving a combination vehicle and notice that the trailer is 'fishtailing' or swinging from side to side. What is the MOST appropriate immediate action to regain control?
- AIncrease engine speed and accelerate out of the skid.
- BSteer gently in the direction of the skid and release the accelerator.
- CApply the trailer hand valve firmly and continuously.
- DApply the service brakes hard and hold them until the vehicle straightens.
Show answer & explanationAnswer & explanation
Correct answer: B. Steer gently in the direction of the skid and release the accelerator.
When a trailer begins to skid or fishtail, the key is to reduce the forces causing the skid and gently steer to correct. Releasing the accelerator reduces engine power and allows the tires to regain traction, while steering into the skid helps align the vehicle.
Why the other options are wrong
- A. Accelerating would likely worsen the skid by decreasing traction and control.
- C. Applying the trailer hand valve during a fishtail can worsen the skid or cause a jackknife by locking the trailer wheels.
- D. Applying service brakes hard would likely cause the tractor to jackknife or further destabilize the trailer.
Trailer Skid Recovery
Techniques used to regain control of a combination vehicle when the trailer begins to fishtail or skid.
- Involves steering into the skid.
- Requires easing off the accelerator.
- Avoids harsh braking or hand valve use.
Memory trick: Steer where you want to go, ease the gas, avoid the tow.