8 CDL A restriction codes every truck driver needs to know

Estimated reading time: 4 minutes

As a commercial truck driver, you'll come across various codes on your Commercial Driver's License (CDL). These include not only endorsements, but restrictions to your license. These codes, known as CDL A restriction codes, determine what you can and can’t do with your license.

Below, we’ll go over the most common Class A restrictions, what impact they have and how to remove them.

What are CDL restrictions?

A CDL restriction is a limitation placed on a driver’s CDL. These restrictions affect things like the vehicles you can drive and when you can drive them. While CDL endorsements let you drive more types of Commercial Motor Vehicles (CMVs), CDL restrictions limit what you can do.

CDL restrictions help keep the roads safe by making sure drivers only drive vehicles they know how to handle. For example, if a driver hasn't passed a test for air brakes, they can't drive vehicles with air brakes.

8 common types of Class A CDL restrictions

There are 8 main restrictions that can be applied to your CDL. It is best to avoid having CDL restrictions on your license, as they can limit the job options available to you.

That said, most restrictions can be removed from your CDL. For each restriction listed below, the way to remove it is included, if applicable.

Note that this is not a complete list of CDL restrictions, as each state may have extra restrictions. Please check your state’s CDL restrictions to ensure you remain compliant.

L restriction – No air brake equipped CMV

The "L” restriction prohibits drivers from operating a CMV with air brakes.

This restriction is applied when a driver does not:

• Pass the Air Brakes Knowledge Test.
• Identify the air brake system components correctly.
• Conduct an air brake systems check properly.
• Take the Skills test in a vehicle with a full air brake system.

Almost all vehicles over 26,000 pounds use air brakes. Because of this, the "L" restriction is very limiting for those looking for a Class A or B CDL job.

How to remove the “L” restriction:

You must pass the air brakes knowledge test and the skills test in a vehicle equipped with air brakes.

Z restriction – No full air brake equipped CMV

Similar to the “L” restriction, the “Z” restriction prohibits drivers from operating a CMV with air brakes.

This restriction is applied when a driver does their test in a vehicle that has partial air brakes or hydraulic brakes. It’s not because they failed part of the test, like the "L" restriction.

How to remove the “Z” restriction:

You must pass the air brakes knowledge test and the skills test in a vehicle equipped with a full air brake system.

E restriction – No manual transmission equipped CMV

With this restriction, drivers are only permitted to drive automatic transmission vehicles.

This restriction is applied when a driver takes their skills test in a vehicle with an automatic transmission. Even though automatic transmissions are becoming more common, having a “E” restriction still limits a driver’s options.

How to remove the “E” restriction:

You must pass the CDL skills test in a manual transmission truck.

O restriction – No tractor-trailer CMV

With this restriction, drivers can't drive a Class A vehicle with a fifth wheel connection.

This restriction is applied when a driver takes their skills test in a Class A vehicle with a pintle hook or other non-fifth wheel connection. Having this restriction means that the driver is not allowed to operate a tractor-trailer. While drivers with an “O” restriction can still operate some Class A vehicles, their jobs options are very limited.

How to remove the “O” restriction:

You must pass the CDL skills test in a tractor-trailer combination vehicle.

M restriction – No Class A passenger vehicle

An "M" restriction limits drivers from driving Class A passenger vehicles.

This restriction is applied when a driver has a Class A CDL, but obtains their “P” or “S” endorsement in a Class B vehicle. Drivers with this restriction can still drive:

• Non-passenger Class A vehicles.
• Class B or C passenger vehicles.

How to remove the “M” restriction:

You must pass your skills test in a Class A vehicle.

N restriction – No class A and B passenger vehicle

Similar to the "M" restriction, the "N" restriction prevents drivers from driving both Class A and B passenger vehicles.

This restriction is applied when a driver has a Class B CDL, but obtains their “P” or “S” endorsement in a Class C vehicle. Drivers with this restriction can still drive:

• Non-passenger Class B vehicles.
• Class C passenger vehicles.

How to remove the “N” restriction:

You must pass your skills test in a Class A or B vehicle. If you pass with a Class B vehicle, an “M” restriction will be applied.

V restriction – CMV medical variance required

The “V” restriction indicates that a driver has a medical variance that goes along with their DOT medical certification.

Medical variances are impairments that can impact a driver’s ability to drive. Common examples include:

• Diabetes.
• Seizures.
• Hearing problems.
• Eyesight impairment.

Unlike other restrictions, this does not impact a driver’s ability to drive certain vehicles. This restriction just means that the driver has a condition requiring a waiver to operate a CMV.

K restriction – CDL intrastate only

Having a “K” restriction means that you’re only allowed to drive commercially within the state your CDL was issued in. There are two main reasons this restriction is applied:

Age:

This restriction applies to those between 18-21 years old. This is because they are not allowed to drive between states per FMCSA regulations. To remove it, you must apply for an upgraded license at your local DMV once you’re over the age of 21.

Medical condition:

The "K" restriction may also apply to those with a disqualifying medical condition. In this case, the driver may not meet federal medical standards, but may qualify for an intrastate medical waiver.

In either case, drivers with a “K” restriction are limited to intrastate driving. This makes them ineligible for most regional and over-the-road driving jobs. However, drivers with this restriction can still find local driving opportunities that move just intrastate freight.

Why do CDL restrictions matter?

Understanding and adhering to CDL restrictions is important for several reasons:

Employment opportunities:

Restrictions can limit the types of jobs you can take. If you want more job opportunities, it can be smart to remove any restrictions. Getting rid of restrictions shows you have more skills, making you a better choice for more employers

Safety:

Restrictions help make sure drivers are only operating vehicles they are proficient with. This helps keep the roads safer.

Compliance:

Violating CDL restrictions can result in penalties such as fines and license suspension.