Backing and Parking Combination Vehicles
What this domain covers
Backing and parking questions test low-speed control of an articulated vehicle. The trailer pivots at the fifth wheel, so small steering inputs produce large trailer movement, and a sharp angle can lead to a jackknife.
Core rules
- Get out and look (GOAL) if unsure. Use a spotter when available and agree on hand signals before backing.
- Back toward the driver's side (left) when possible, because the blind side is harder to judge. Use both mirrors and watch the trailer's rear corners.
- Back slowly; if the trailer goes wrong, pull forward to straighten rather than oversteering. A combination should be backed in small corrections.
- Avoid backing at a sharp angle, especially on slippery surfaces; the trailer can push the tractor into a jackknife.
- When parking, set the tractor and trailer parking brakes, chock wheels on a grade, and turn wheels into the curb. Use the trailer brake to hold the trailer while spotting.
Worked example
You need to back into a dock on the right. Position the tractor so the trailer is angled toward the dock, then back slowly while watching the trailer's right rear in the mirror. If the trailer's rear drifts left, stop, pull forward, and re-establish the angle. Do not crank the wheel hard and continue; that increases the jackknife angle.
Traps that cost marks
Backing blind side when a left-side approach is possible; backing without a spotter; oversteering; forgetting to set the trailer brake; and parking on a grade without chocks. Also, do not rely on mirrors alone when the trailer's rear is obscured.