How to Back a Tractor-Trailer: Straight, Offset, Alley Dock

For truck drivers

Updated September 28, 2026

To back a tractor-trailer, go slowly in your lowest reverse gear and watch both mirrors. Turn the steering wheel the opposite way from where you want the trailer to go. Once the trailer starts to turn, turn the wheel back to follow it.

Fix drift early, pull forward to set up again when you need to, and get out and look whenever you are not sure. The CDL manual says backing is always dangerous, so avoid it when you can.

6Backing and parking exercises in manual section 12

1 lookAllowed on the straight line backing exercise

2 looksMost allowed on the other backing exercises

3 ftHow close the rear must stop to the end of the alley

This guide walks through each backing maneuver on a tractor-trailer: straight line, offset, alley dock and parallel parking. The rules and the test scoring come from the Colorado Commercial Driver License Manual and the federal CDL rules. The step lists stick to what the manual says.

The Safe-Backing Basics

You cannot see everything behind a truck, so the manual’s first rule is to avoid backing whenever you can. When you park, try to park so you can pull forward to leave. When you have to back, the manual gives these rules (section 2.2.4):

Start in the right position.Put the truck where it can back most safely. That spot depends on the kind of backing you have to do.
Look at your path.Before you start, get out and walk around the truck. Check your clearance to the sides and overhead, in and near the path you will take.
Use the mirrors on both sides.Check them often. If you are unsure, get out and check your path again.
Back slowly.Use the lowest reverse gear. You can fix steering errors more easily and stop fast if you need to.
Back toward the driver’s side.You can see the rear of the truck out the side window. The manual says it is worth going around the block to set this up.
Use a helper.There are blind spots you cannot see. Your helper stands near the back of the truck where you can see them. Agree on hand signals first, including one for stop.

Which Way to Turn the Wheel

In a car or a straight truck, you back by turning the top of the steering wheel the way you want to go. With a trailer, the manual says it works the opposite way. Once the trailer starts to turn, turn the wheel the other way to follow it.

Wheel top left

Trailer goes right

Wheel top right

Trailer goes left

From the manual’s figure 6.5, Backing a Trailer

When the trailer starts to drift off your path, the manual says to correct it right away by turning the top of the steering wheel toward the drift. Small, early corrections are easier than big, late ones.

Straight Line Backing

Federal rules require every CDL applicant to show they can back in a straight line and check path and clearance while backing (49 CFR 383.113). It is also the setup for most real backing, because the manual says to position your rig so you can back straight whenever you can.

Straight line backing: back through the lane without touching the cones or lines.

Line up straight.Position the rig so you can back in a straight line. Pull forward first if you need to.
Check the path.Get out and look at the space behind the trailer and overhead before you start.
Back slowly in the lowest reverse gear.Slow speed lets you correct before you get far off course.
Watch both mirrors.Check the outside mirrors on both sides often.
Correct drift right away.As soon as the trailer starts to drift, turn the top of the wheel toward the drift.
Pull up if you need to.If the trailer gets too far off, stop, pull forward to straighten out, and start again.

Offset Backing, Left and Right

Offset backing moves the rig from one lane into the lane beside it, in reverse. On the manual’s test layout you drive straight forward to the outer boundary, then back into the other lane until the front of your truck has passed the first set of cones.

Offset backing: start in one lane and finish straight in the lane beside it.

Offset left backs into the lane to your left rear. That is the driver’s side, so you can watch the trailer out the window.
Offset right backs into the lane to your right rear. That is the side you see least, so use your mirrors, a helper or a look.
Finish straight. The trailer has to end up straight in the new lane without touching the cones or lines.

Alley Dock (90-Degree) Backing

An alley dock backs the rig into an alley that sits at a right angle to where you start. The manual’s version is a sight-side back: you drive past the alley, stop parallel to the outer boundary, then back in.

Alley dock: back around the corner and stop straight, with the rear within 3 feet of the end.

Set up on the sight side.Drive past the alley so it ends up on your driver’s side as you back. Stop parallel to the outer line.
Look first.Check the alley, the corners and anything overhead before you start.
Back slowly and turn the trailer toward the alley.Remember the wheel works opposite. Then follow the trailer in.
Straighten in the alley.The rig has to finish straight within the lane.
Stop at the end.On the test, the rear of the trailer has to stop within 3 feet of the rear of the alley without touching the cones or lines.

Parallel Parking a Tractor-Trailer

The manual lists two parallel parking exercises. In both, you drive past the space with your rig parallel to it, then back in without crossing the front, side or rear lines. The whole rig has to end up inside the space.

Driver side. The space is on your left, so you can watch the trailer out the window as you back.
Conventional. The space is on your right, the side you see least. Take it slow and check your mirrors often.

Parallel park, driver side: pull past the space, then back in until the whole rig is inside the lines.

Sight Side vs Blind Side Backing

Sight side means backing toward the driver’s side. You can lean out and see the trailer, the corner and the space. The manual says to back to the driver’s side whenever you can.

Blind side is the opposite: backing toward the right side. The manual calls that very dangerous, because you cannot see as well. If you have to back to the right, slow down, use a helper, and get out and look more often.

Car hauler parked in an open lot with a full load of SUVs on both decks — An Accelerated rig carries up to nine cars. The same backing rules apply to every tractor-trailer.

Get Out and Look

The manual puts it plainly: if you are unsure of your path, get out of the vehicle and check it. Do it before you start, and again whenever the picture in your mirrors does not match what you expect.

Do it safely every time. Set the parking brake, put the truck in neutral, and climb down facing the truck with three points of contact.

On the CDL test, every time you open the door or leave your seat counts as a look, and looks are limited (see below). Opening the door while the truck is moving can be an automatic fail.

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Backing on the CDL Test

Backing is part of the basic control skills test. The Colorado manual prints two versions of that test. Your state’s manual and your examiner will tell you which exercises you get, and the examiner explains each one before you start.

Manual section	Exercises	Looks allowed
Section 12	Straight line backing, offset back right, offset back left, parallel park (driver side), parallel park (conventional), alley dock	1 on straight line backing, up to 2 on the others
Section 12M	Forward stop, straight line backing, forward offset tracking, reverse offset backing	1 free look on straight line backing, 2 on reverse offset backing

How the examiner scores you:

Encroachments. Each time any part of the rig touches or crosses a line or cone counts as an error.
Pull-ups. Stopping and pulling forward to fix your position is a pull-up. The first ones are free, but too many count as errors. Section 12M allows 1 free pull-up on straight line backing and 2 on reverse offset backing.
Looks. Opening the door or leaving your seat counts as a look, up to the limits above.
Final position. If the rig does not finish where the examiner told you, you fail the basic control test.

Federal rules also require every applicant to show they can back along a curved path (49 CFR 383.113). Still in training? See our guide to entry-level driver training.

Haul Cars With Accelerated

We have hauled finished vehicles for the automakers since 1999, and we contract with our drivers. You get a $5,000 sign-on bonus, paid in your first month. We ask for 3 years of CDL-A driving and 1 year of verifiable 9-car experience. Our driving test comes at orientation, not before you apply.

Apply With Accelerated

See everything we ask for on our careers page.

Backing a Tractor-Trailer FAQs

Which way do you turn the wheel when backing a trailer?

The opposite way from where you want the trailer to go. Turn the top of the wheel left to send the trailer right, and right to send it left. Once the trailer starts to turn, turn the wheel back to follow it.

What is straight line backing?

It is backing the rig in a straight line between two rows of cones without touching them. Federal rules require every CDL applicant to show they can back in a straight line and check path and clearance while backing.

What is sight side backing?

It is backing toward the driver’s side, where you can see the trailer out the window. The CDL manual says to back to the driver’s side whenever you can, even if it means going around the block.

What is an alley dock?

It is backing the rig into an alley at a right angle to where you start. On the manual’s test, you back in from the sight side and stop straight, with the rear within 3 feet of the end of the alley.

How many times can you get out and look on the CDL backing test?

It depends on the exercise. The Colorado manual allows one look on straight line backing and up to two on the other backing exercises. Opening the door or leaving your seat counts as a look.

Sources

Last checked September 28, 2026. Test layouts and scoring vary by state. Check your state’s CDL manual and follow your examiner’s instructions.