CDL Vehicle Combination Practice Test

How should air and electrical lines from the tractor to the trailer be positioned?

1. Loosely attached

2. Secured but with enough to loop the turn

3. Tightly secured

4. Completely disconnected

The correct answer is: Secured but with enough to loop the turn

The correct positioning of air and electrical lines from the tractor to the trailer is to secure them but also ensure there is enough slack to allow for movement, such as when making turns. This helps to prevent strain on the lines, which could lead to damage or disconnection while the vehicle is in operation. Securing the lines properly minimizes the risk of them dragging on the ground or interfering with the vehicle's mechanics, but leaving enough slack is crucial to accommodate the natural articulation and movement of the truck and trailer as they navigate turns and uneven surfaces. If the lines were too loosely attached, they could become disconnected or tangled, leading to serious operational issues. Conversely, if they were tightly secured or completely disconnected, it would hinder functionality and safety, as the air lines are critical for braking and the electrical lines are necessary for lights and other electronic functions on the trailer.