The control of a single unit vehicle is maintained in the same manner as that of a passenger vehicle.

In backing a tractor with a semi-trailer, the front wheels of the tractor must be turned in a direction opposite to that in which it is desired to move the rear of the trailer.

Depending on the amount of change in direction, the tractor must follow in a track related to the track of the trailer, otherwise a jackknife position will be reached. The tracking pattern for a normal right angle turn would be an "S" shaped curve.