CDL Combination Vehicles TestDriving Combination Vehicles SafelyMedium
When driving a combination vehicle, you notice that your trailer is starting to swing wide on a curve. What is the most appropriate immediate action to take?
- AApply the trailer hand brake to bring the trailer back in line.
- BEase off the accelerator and make slight steering adjustments to maintain control.
- CSteer sharply into the curve to compensate for the swing.
- DSpeed up slightly to pull the trailer straight.
Show answer & explanationAnswer & explanation
Correct answer: B. Ease off the accelerator and make slight steering adjustments to maintain control.
If a trailer starts to swing wide, easing off the accelerator reduces the force pushing the trailer out, and slight steering adjustments can help guide it back into the proper path without overcorrecting or causing a loss of traction.
Why the other options are wrong
- A. Applying the trailer hand brake can cause the trailer wheels to lock up, leading to a trailer jackknife, which is more dangerous than a wide swing.
- C. Steering sharply can cause the tractor to lose traction or overcorrect, leading to a jackknife or rollover.
- D. Speeding up will increase the centrifugal force acting on the trailer, making the swing worse and potentially causing the trailer to overturn.
Trailer Swing Correction
Actions taken to bring a trailer back into alignment when it starts to swing wide on a curve.
- Reduce speed by easing off the accelerator.
- Make small, gentle steering corrections.
- Avoid sudden braking or sharp steering.
- Anticipate curves and reduce speed before entering them.
Memory trick: Smooth and slow, let the trailer flow.