A tractor-trailer is an articulated vehicle combination weighing about 80,000 pounds. The combination consists of a vehicle that does the towing -- the tractor -- and one or more trailers that carry the freight. Learning how to back is an essential part of a training program. Schools vary, but most devote 50 to 60 hours to teaching backing. The training time is divided among the students. Most schools allocate one instructor to three or four students.

To back a tractor-trailer combination, you create an angle at the articulation point that will allow you to guide the trailer into position by steering the tractor while moving in reverse gear.

Back the trailer to the left -- rather than the right -- whenever possible. This is called sight-side backing, and gives a better view of the area into which you are backing. Inspect the area into which you will back for anything that might damage the vehicle. Check the area over the vehicle. It should be clear of anything that might damage the top. Check the area under the truck for anything that may have rolled underneath, which might damage the underside of the vehicle or the tires. Return to the truck cab. Adjust your mirrors to provide a good view of both sides of the vehicle.

Create the angle between the tractor and the trailer by jacking. Jacking is turning the tractor so that it is at an angle to the trailer. As the tractor moves backward, this angle will direct the rear of the trailer toward the area into which you want to back. To jack the tractor, turn the top of the steering wheel opposite the direction in which you want the rear of the trailer to go. Another method is to place your hand on the bottom of the steering wheel. Move your hand -- and the wheel -- in the direction you want the trailer to go.

Shift into reverse. If you jacked the tractor by turning the steering wheel to the right, reverse the steering angle by turning the wheel to the left. If you jacked the tractor by turning the steering wheel to the left, turn it to the right. As the trailer moves backward, the tractor will "follow" it, traveling in the same path. Once the trailer is headed towards the space, turn the steering wheel to the right or left. Adjust as necessary to keep the trailer centered in the space.

Use your mirrors and watch both sides of the rig. Roll down the window if you must to get a better view but don’t open the driver’s side door and lean out of it. That makes it impossible to use the right side mirror and increases the risk of being injured.

Back slowly. Be prepared to stop immediately. Keep your right foot off the throttle and poised over the clutch instead.

Maintain idle speed. If you directed the trailer by turning the steering wheel to the left, straighten the tractor and trailer by turning the steering wheel even more to the left. If you directed the trailer by turning the steering wheel to the right, turn it even more to the right. When the tractor is aligned with the trailer, and the combination forms a straight line, use the steering wheel to straighten the tractor wheels.