What You Can (and Can't) Do With a CDL

Operating certain vehicles, even with a CDL (commercial driver’s license), may require you to remove restrictions or add endorsements. Additional testing and fees will be required to meet these criteria.

CDL Restrictions

Restrictions placed on a commercial driver’s license may keep you from operating some vehicles. Here are the most common federal restriction codes for CDL operators.

L Restriction: Prohibits the operation of a vehicle with full air brakes. This restriction is placed on a license when:

  • Take the road skills test in a vehicle that does not have a full air brake system
  • Fail the Air Brakes Knowledge Test
  • Fail to conduct a proper air brakes system check
  • Incorrectly identify the components of an air brakes system

Z Restriction: Also restricts the operation of a vehicle with full air brakes if you tested in a vehicle with an air over hydraulic brake system.

E Restriction: Prohibits the operation of a vehicle with a manual transmission. This restriction is placed on a license when you take your skills test in a vehicle with an automatic transmission.

M Restriction: Restricts you to the operation of only Class B or C passenger vehicles or school buses. This restriction is placed on a license if you have a Class A CDL, but you earned your passenger vehicle endorsement in a Class B vehicle.

N Restriction: Restricts you to the operation of Class C passenger vehicles/school busses only. An N restriction is added to the license of Class B drivers who earn their passenger endorsement in a Class C vehicle.

O Restriction: Prevents the operation of a Class A vehicle with a fifth wheel connection. This restriction is added if you take your skills test in a vehicle with a ball hitch or pintle hook connection.

V Restriction: Means that a medical variance has been reported by the Federal Motor Carrier Safety Administration (FMCSA). This may be due to a diabetic or vision waiver being issued by the FMCSA.

There can be other restrictions that may be placed on your CDL, depending on state and local laws.

CDL Endorsements

If you have met the criteria for a CDL, some commercial vehicles require additional written and driving tests before being allowed to operate them.

This list reviews the more common federal endorsements that may be needed, and the tests that your state will require.

H Endorsement: This permits the transport hazardous materials and will require a written knowledge test.

N Endorsement: Allows the operation of tanker trucks after taking a written knowledge test.

P Endorsement: This will allow the operation of a vehicle carrying a specified number of passengers (the exact number may depend on the state that you are in). This endorsement will require a written knowledge and road skills test.

S Endorsement: Permits the operation of school buses and requires both a road skills test and a written knowledge test.

T Endorsement: Will allow you to tow a double or triple trailer and will necessitate a written knowledge test.

X Endorsement: Requires a written knowledge test to allow for the operation of tanker and HAZMAT vehicles.

Your state can help you determine the steps needed to obtain these endorsements or remove restrictions.