CDL Vehicle Combination Practice Test

What is the effect of off-tracking or cheating during turns?

1. The rear wheels follow a tighter path

2. The trailer detaches from the tractor

3. The tractor towing a 45 feet trailer follows a wider path

4. The tractor remains stationary

The correct answer is: The tractor towing a 45 feet trailer follows a wider path

When navigating turns, particularly with a combination vehicle like a tractor-trailer, off-tracking—also referred to as cheating—occurs because the rear wheels of the vehicle do not follow the same path as the front wheels. This is especially prominent when the trailer being towed is longer. The correct answer highlights that when a tractor towing a long trailer turns, the trailer's rear wheels swing out wider than the front wheels. This happens due to the geometry of the vehicles; the longer the trailer, the more pronounced the effect will be. Thus, while the front of the tractor takes a path that is relatively close to the desired turning radius, the back of the trailer will cut into a wider area. This effect is critical for drivers to understand when making turns, to avoid running over curbs, hitting obstacles, or getting into accidents with nearby vehicles. Being aware of this characteristic allows drivers to adjust their turning maneuvers effectively to accommodate the wider path followed by the trailer.