How to remove the air brake restriction (L or Z) from your CDL
What the L restriction means
An L on your CDL means no air brake equipped CMV. You cannot drive a commercial vehicle with any type of air brakes. Under federal rules, you get it if you fail (or do not take) the air brake knowledge test, or if you take your skills test in a vehicle without air brakes.
What the Z restriction means
A Z on your CDL means no full air brake equipped CMV. You get it if you take your skills test in a vehicle with air over hydraulic brakes. You can drive a vehicle with air over hydraulic brakes, but not one whose brakes work fully on air, which is most tractor-trailers.
Federal rules count any brake system that works fully or partly on air as air brakes, which is why the two restrictions are different.
How to remove the restriction
Federal rules (49 CFR 383.135) say you do not have to retake the whole skills test. To remove an L or Z restriction:
- Pass the air brake knowledge test (80 percent or more).
- Do the air brake pre-trip inspection (the air brake checks of the pre-trip).
- Pass a skills test in a vehicle with full air brakes. Your state may give a modified test that only shows you can safely operate the full air brakes.
You need to bring a vehicle with full air brakes to the test. Many drivers rent one from a local school. Study for the knowledge test with our free practice tests.
Do you need ELDT to remove it?
No. The FMCSA says drivers removing an L, Z or E (manual transmission) restriction are not subject to the Entry-Level Driver Training rules. You can go straight to your state DMV.
ELDT does apply if you are doing something else at the same time, like a Class B to Class A upgrade or a first-time Passenger, School Bus or HAZMAT endorsement. See the Class B to A upgrade and do I need ELDT.
What it costs
There is no single national price. You will usually pay your state's fees for the knowledge test, the skills test and a new license, plus the cost of renting a truck with full air brakes if you do not have one. Fees are set by each state, so check with your state DMV.
Avoid the restriction the first time
If you have not taken your skills test yet, take it in the same type of vehicle you want to drive. If you want to drive tractor-trailers, test in a truck with full air brakes and pass the air brake knowledge test, so the L or Z never goes on your license.
Questions drivers ask
What is the difference between the L and Z restriction?
L means no air brakes of any kind. Z means no full air brakes, because you tested in a vehicle with air over hydraulic brakes.
Do I need entry-level driver training to remove an air brake restriction?
No. The FMCSA says drivers removing an L, Z or E restriction are not subject to the ELDT rules.
Do I have to retake the whole CDL skills test?
No. Federal rules let your state give a modified skills test focused on the air brakes, plus the air brake pre-trip inspection and the air brake knowledge test.
How much does it cost to remove the air brake restriction?
It depends on your state's test and license fees, plus renting a truck with air brakes if you need one. Check with your state DMV.
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