Earning your class A commercial driver’s license (CDL) allows you to drive vehicles with a gross combination weight rating (GCWR) of 26,001 pounds or more with trailers of 10,000 pounds or more. This includes semi-trucks, but a standard CDL does not permit you to drive every single type of tractor-trailer. There are two different factors that can change which vehicles you can and cannot drive with your license: endorsements and restrictions. Endorsements are added to your CDL and are “extra” qualifications. Restrictions prevent you from driving specific types of vehicles or under certain conditions. The air brake restriction is one example and may reduce the number of jobs available to you after earning your license.
More information about the CDL air brake restriction:
What Are Air Brakes?
Brakes stop a vehicle from moving by converting the energy from motion into heat. Most smaller passenger vehicles have a hydraulic system, which uses fluid to accomplish this. Conversely, large vehicles such as semi-trucks typically use compressed air instead. This is because, unlike brake fluid, air does not need to be refilled for the system to work. Air brakes are also safer for vehicles of this size and there are typically a few different back-ups in place in case there are any issues.
The Two Air Brake Restrictions
Although many people will refer to one air brake restriction, there are technically two different codes that could be placed on your license. Both of them limit your ability to drive vehicles with air brakes, but they are slightly different and you will need to make sure you take the proper steps to remove both.
L Restriction
If you have the L restriction on your CDL, you will not be able to drive a vehicle with any type of air brake system. This will be added to your license if you fail the air brakes portion of the written exam or CDL skills test. You can also have this restriction if you take the skills test using a vehicle that does not use air brakes. To remove it, you will need to pass all sections of the CDL exam relating to air brakes.
Z Restriction
Taking the skills test using a vehicle that has only a partial air brake system will result in the Z restriction being placed on your license. You will be unable to drive semi-trucks with a full air brake system. To remove this air brake restriction, you need to take the skills test with a vehicle that is fully equipped with air brakes.
We Can Help You Earn Your CDL
At HDS Truck Driving Institute (HDS truck driving school), we can help you earn your CDL and start on the road to a rewarding trucking career. We work with you to remove restrictions, including those for air brakes, so you have more opportunities available to you after graduation. Our program also includes material for three endorsements: hazardous materials (hazmat), tanker, and doubles/triples.
