TM9-2330-207-14
2-34. OPERATI NG TOWING VEHICLE AND SEMITRAILER
a. Driving. When driving the truck tractor and semitrailer, the overall length of the unit must be kept in
mind when passing other vehicles and when turning. Because the unit is hinged in the middle, turning and
backing are also affected. The semitrailer's payload will affect stopping and off road meneuverability.
b. Turning. When turning corner, allow for the fact that the semitrailer wheels turn inside the turning
radius of the truck tractor. To make a right turn at a road intersection, drive the towing vehicle about half-
way into the intersection and then cut sharply to the right. This will allow for the shorter turning radius of
the semitrailer and will keep it off the curb.
c. Stopping. In normal operation, the brakes of the truck tractor and the semitrailer are applied at the
same time when the driver steps on the brake pedal. Brake pressure must be applied gradually and smoothly.
The semitrailer brakes may be applied separately by using the brake control lever on the truck tractor steering
column. On steep down grades or slippery surfaces, the semitrailer brakes must be applied before the truck
tractor brakes. This will reduce the possibility of jack-knifing the semitrailer.
d. Parking. When the truck tractor and the semitrailer are to be parked and left unattended, set the park-
ing brake on the truck tractor and apply the brakes on the semitrailer. Turn off the truck tractor engine before
leaving the cab. Block the semitrailer wheels with chock blocks.
e. Backing. Whenever possible, the assistant driver or another person will act as a ground guide to assist
and direct the driver. Adjust all rear view mirrors before backing. When backing, the rear of the semitrailer
will always move in the opposite direction of that in which the front wheels are turned. When the wheels of
the truck tractor are turned to the right, the rear of the semitrailer will go to the left. When the semitrailer
has turned and backing in a straight line is required, turn the truck tractor wheels in the direction the semi-
trailer is moving. This will slowly bring the truck tractor and the semitrailer into a straight line.
