Master the System.
Stop with Confidence.

The CDL Air Brakes test is a written knowledge exam required for any driver operating a commercial vehicle equipped with air brakes. It covers air brake system components, inspection procedures, stopping distances, and emergency procedures. If you don't pass, you'll receive a restriction on your CDL that limits you to vehicles without air brakes.

Key PSI values include: governor cut-out at approximately 125 PSI, low-pressure warning activation below 60 PSI, and spring brakes engaging automatically between 20-45 PSI. You should also know the air pressure build-up rate of 85 to 100 PSI within 45 seconds for dual air systems.

Kaplan's CDL Air Brakes Prep Product costs $29 and includes practice questions covering all air brake system components, PSI thresholds, and test procedures with detailed answer explanations.