CDL Alley Dock Backing: The 90 Degree Back
Last updated · By David Nelson
In the alley dock you drive past a dock opening, then back the trailer at a 90 degree angle into the box and stop with the rear of the trailer close to the back line.
Your setup decides the result. Pull up far enough, angle the tractor away from the dock, and start the trailer turning early and slowly.
The course
The dock is a box about 12 feet wide and as deep as your trailer. A line of cones in front of it marks how far you can swing the tractor. You approach with the dock on your left, so you back from the driver's side.
Scoring basics
- Pull-ups beyond the free ones cost points.
- Encroachments, especially the front of the tractor crossing the outer line, cost points.
- G.O.A.L. is allowed a limited number of times. Use one right before the trailer enters the box.
- Final position: the trailer must be inside the box and within a few feet of the rear line without touching it.
Setup and steps
- Drive past the dock until your trailer tandems are just past the far side of the opening.
- Turn away from the dock slightly to set an angle, then stop.
- Back slowly while turning toward the dock until the trailer starts to swing in.
- Follow the trailer with the tractor and straighten once it lines up with the box.
- G.O.A.L. near the end to judge the distance to the back line.
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Frequently asked questions
Is the alley dock the hardest backing maneuver?
Many drivers say yes, because it combines a big turn, a tight box and a precise final stop.
How close do I need to get to the back of the dock?
Most states want the rear of the trailer within about 3 feet of the rear line without crossing it. Check your manual.
Why do I keep cutting the corner cone?
You are probably starting the turn too early or with too little setup angle. Pull further past the opening first.
Can I use more pull-ups to fix the alley dock?
Yes, but each one past your free limit costs points. A good setup means you rarely need them.
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