What is Off-Tracking in a Large Truck?
WHAT HAPPENS IN OFF-TRACKING?
Off-tracking is a term used to describe what happens with large trucks, or any vehicle with more than one set of wheels when the rear wheels don’t follow the same path as the front wheels while moving through a turn or a curve. Instead, the rear wheels will follow the shorter of the two paths, instead of tracking behind the path of the front wheels.
In eighteen-wheeler trucks, there are several variables that will determine when and how the truck wheels off-track while turning. These factors include:
- The distance between the rear wheels and the kingpin – when there is more distance between the rear wheels and the kingpin, the more off-tracking will occur;
- The sideways drag of the back tires, the more sideways drag, the greater the off-tracking will be;
- The radius of the curve for which the truck is attempting the turn.
WHAT TRAINING MUST A MOTOR CARRIER PROVIDE TO TRUCK DRIVERS TO REDUCE AND PREVENT OFF-TRACKING CRASHES FROM OCCURRING?
A reasonably safe motor carrier trains its professional drivers to slow down and adjust speed before turning. The sharper the turn, the slower the truck should travel through the turn. By slowing down, the truck driver can use all the space that is available to safely execute the turn.
The truck driver should shift into the proper gear before beginning to execute the turn. This will allow the driver to keep both hands on the steering wheel while executing the turn.
To avoid hitting the curb during a right turn, the truck driver must pull the truck about one-half the length of the truck past the corner of the curb before beginning the turn. Then, the driver should accelerate slightly and smoothly through the turn while checking the right and left mirrors to avoid collisions with other motorists in the area. The driver should also position the trailer so no vehicles could enter the area between the trailer and the curb.
After completing the turn, the driver should turn the steering wheel immediately back to the straight position.
A right turn becomes dangerous and increases the risk of harm to the motoring public when he or she neglects to reduce speed while approaching the turn, does not down shift, accelerates into the turn, shifts while turning, leaves too much space between the curb and the trailer, does not allow for the differential in off-tracking; and does not keep watch of the right and left mirrors during the turn maneuver and after the turn maneuver.
OFF TRACKING IN LEFT TURNS
The approach of a reasonably safe truck driver in executing a right turn maneuver is similar to the right turn. The driver will first shift into the correct gear to avoid shifting during the turn and to allow him or her to keep both hands on the steering wheel while turning. The driver also should leave as much room as possible towards the far right side to allow enough room to complete the turn.
If the driver turns too soon or too tightly, off-tracking can cause the left side of the trailer or tractor to strike another vehicle. The driver also should constantly check both left and right mirrors while completing the turn.