CDL General Knowledge TestCombination Vehicles (if applicable)Hard
A driver is maneuvering a combination vehicle through a tight turn. To avoid 'off-tracking' (trailer cutting the corner), what is the most effective technique?
- AUse the trailer hand brake to slow the trailer during the turn.
- BIncrease speed significantly through the turn to reduce the turning radius.
- CStart the turn from the center of the lane.
- DBegin the turn by swinging wide to the left before turning right, or vice-versa.
Show answer & explanationAnswer & explanation
Correct answer: D. Begin the turn by swinging wide to the left before turning right, or vice-versa.
Off-tracking causes the rear wheels of a combination vehicle to follow a shorter path than the front wheels. To counteract this, a driver must swing wide in the opposite direction of the turn before initiating the turn, effectively creating more space for the trailer to follow without hitting curbs or other objects.
Why the other options are wrong
- A. Using the trailer hand brake during a turn can cause the trailer to skid or jackknife, leading to loss of control.
- B. Increasing speed in a turn reduces control and increases the risk of a rollover, and does not effectively mitigate off-tracking.
- C. Starting from the center will likely cause the trailer to off-track and hit the curb or other obstacles.
Off-tracking Prevention
To prevent off-tracking, a driver must swing wide in the opposite direction of the turn to allow the trailer sufficient room to follow the tractor.
- Trailer cuts corners.
- Swing wide opposite turn.
- Creates space for trailer.
Memory trick: To avoid a cut, take a wider strut.