Earning your commercial driver’s license (CDL) allows you to operate a commercial motor vehicle (CMV). To earn this license, you will need to pass a written exam and a skills test. In addition to understanding what is necessary to earn a standard license, you should also understand CDL restrictions. These are codes that can be placed on your license that prevent you from driving certain types of CMVs or driving under specific conditions. (An exception to this is the V restriction. This indicates that there is a medical variance on your CDL. However, it does not directly affect what vehicles you can drive.)
Some of the most common CDL restrictions include:
K Restriction
Per federal CDL requirements, you need to be 21 years of age or older to operate a CMV across state lines. However, you can drive within the state if you are 18 or older. In this case, a K restriction will be placed on your license to indicate that your CDL is valid for intrastate travel only.
E Restriction
If your CDL has an E restriction, you will not be able to drive a CMV with a manual transmission. This can make finding a trucking job more difficult, as many semi-trucks use manual transmissions. You will have an E restriction on your license if you take the skills test using a vehicle that has an automatic or semi-automatic transmission.
O Restriction
An O restriction means you cannot operate a tractor-trailer. You will have this restriction on your license if you take your skills test with a vehicle that has a non-fifth wheel connection or pintle hook.
Air Brake CDL Restrictions
Air brakes use compressed air to stop a vehicle, as opposed to traditional hydraulic braking systems that use brake fluid. Because air brakes are often more effective at stopping larger vehicles, they are common for CMVs. There are two different types of air brake restrictions that can be placed on your CDL and either one can limit the truck driving jobs that are available to you.
L Restriction
If your license has an L restriction, you will not be able to operate a motor vehicle that has air brakes. This restriction will be placed on your CDL if you fail the air brakes portion of the written test and/or the air brake inspection during your skills test. Your license will also have an L restriction if you do not use a vehicle with air brakes for your skills test.
Z Restriction
A Z CDL restriction prevents you from operating a CMV with a full air brake system. This restriction applies if you took your skills test with a vehicle that only had a partial air brake system.
CDL School in Tucson, AZ
If you are interested in earning your CDL, HDS Truck Driving Institute (HDS truck driving school) can help. Our programs cover material from the CDL test and we will work with you to help you avoid restrictions on your license. Our students are also able to earn endorsements for hazardous materials (hazmat), tanker vehicles, and doubles/triples.
