Turns, Lane Changes, and Backing
Turns, Lane Changes, and Backing
This domain tests low-speed control of a combination vehicle. The exam focuses on off-tracking, right and left turns, mirror use, lane changes, and safe backing.
Turns
- The trailer’s rear wheels follow a shorter path than the tractor’s front wheels, so the trailer cuts the corner. This is off-tracking.
- For a right turn, approach in the proper lane, signal early, and swing wide enough to keep the trailer tires off the curb without entering another traffic lane.
- Watch the trailer tires in the mirrors throughout the turn. If the trailer is tracking too close to the curb, stop and correct before continuing if it is safe to do so.
- Left turns also require room; do not turn so wide that the trailer enters an adjacent lane.
Lane changes and backing
Signal, check mirrors and blind spots, and move smoothly. A long trailer may still be in the old lane after the tractor has changed. For backing, use GOAL-Get Out And Look-use a spotter when available, back slowly, and make small steering corrections. Pull forward to correct a bad angle rather than forcing the trailer.
Worked example
A 53-foot trailer is making a right turn at a tight intersection. The tractor clears the curb, but the trailer’s right rear tires move inside the turn and approach the curb. The driver should have swung wider before the turn and watched the trailer tires in the right mirror. Continuing to crank the wheel tighter increases off-tracking.
Traps that cost marks
Cutting corners, oversteering, backing without a spotter, and assuming the trailer follows the tractor exactly are common errors. Do not back in traffic when a pull-up will correct the angle.
Key points
- Trailer rear wheels off-track inside turns.
- Swing wide enough for a right turn without crossing lanes.
- Watch trailer tires in the mirrors during turns.
- Signal and check blind spots before lane changes.
- Use GOAL, a spotter, and small corrections when backing.