Connecticut CDL Combination Vehicles Permit Practice Exam: Study Guide & Prep

When air lines are crossed in a combination vehicle, it is crucial to fix the lines before proceeding. Properly connected air lines ensure that the trailer’s braking system functions correctly. If the lines are crossed, this could lead to a severe braking failure, as the brake signals may not reach the trailer properly, putting you and others on the road at significant risk.

For example, if the supply line is connected to the service line on the trailer, the trailer brakes may not activate when you attempt to stop, leading to a dangerous situation. Therefore, it’s essential to check and correct any issues with the air lines to ensure that all connections adhere to safety standards and vehicle operational guidelines. Taking the time to fix the lines helps maintain vehicle safety and compliance with regulations.