Offtracking, Turning, and Lane Positioning
Offtracking, Turning, and Lane Positioning
This domain tests whether you understand that the rear trailer does not follow the tractor's path. Offtracking is the difference between the path of the front wheels and the path of the rear wheels.
Offtracking
- Rear wheels track inside the front wheels in a turn.
- With multiple trailers, the last trailer cuts the corner the most.
- The longer the combination, the more room you need.
Turning
- Swing wide before a turn, but do not swing into another lane without checking.
- Slow down before the turn, not during it.
- Watch the rear trailer in the mirrors; it may clip a curb or sign.
- Right turns may require using part of the left lane to keep the rear trailer off the curb.
Lane positioning
- Keep the combination centered; wind and road crown cause drift.
- Check mirrors often, especially before lane changes.
- Signal early and allow extra time.
Worked example
At a right turn, the lead trailer clears the curb, but the rear trailer cuts inside. Move left before the turn, keep the tractor slow, and watch the rear trailer's tires in the right mirror. If the rear trailer is heading for the curb, stop and correct rather than accelerating.
Traps
Turning too fast, watching only the lead trailer, and forgetting that the last trailer has the greatest offtracking. Also, swinging wide without checking traffic.