The Z Restriction
Applied when you pass the air brakes knowledge test but take the skills test in a vehicle with an air-over-hydraulic braking system.
What it actually stops you doing
A restriction is printed on the licence and is enforceable roadside. Driving outside it is driving outside your licence class, with the same consequences — so an employer will check it before they hire you, whatever your experience.
How to remove it
Retake the skills test in a vehicle without the limitation — there is no written test for this one. The restriction records what you demonstrated in the vehicle you brought, so the only way to change it is to demonstrate again in a different vehicle.
Book with the vehicle you intend to drive professionally. Borrowing whatever was available is how most drivers end up with this restriction in the first place.
See all CDL restriction codes →
More CDL guides
See every CDL knowledge test and guide →
Frequently asked questions
What does the Z restriction mean?
Applied when you pass the air brakes knowledge test but take the skills test in a vehicle with an air-over-hydraulic braking system.
How do I remove the Z restriction?
Retake the skills test in a vehicle without the limitation — there is no written test for it.
