Vermont Air Brakes Practice Test
Required if the vehicle you'll drive has air brakes — which in practice means nearly every combination vehicle and most straight trucks. The test covers the parts of an air-brake system (compressor, governor, tanks, valves), the specific pressures where things happen (cut-in, cut-out, low-air warning, spring-brake pop-out), and the inspection sequence for leaks and warning devices. Fail this knowledge test or take the skills test in a vehicle without air brakes, and your license carries an air-brake restriction that keeps you out of most trucking jobs.
Who needs it: Anyone who'll drive a vehicle with air brakes. Skipping it puts an L or Z restriction on the license.
Sample practice questions
ABS (antilock braking system):
Answer: Keeps wheels from locking and helps you keep control during hard braking — ABS prevents lockup and helps control; it does not necessarily shorten stopping distance and is an addition to normal brakes.
In stab braking, after the wheels lock you:
Answer: Release the brakes, then reapply fully once the wheels start rolling again — Release on lockup; when wheels roll again (up to one second later), apply fully again.
The application pressure gauge shows:
Answer: How much pressure you're applying to the brakes — It shows the pressure you're applying to the brakes; it's not on all vehicles.
Common mistakes on the Air Brakes test
- Mixing up the pressure numbers — cut-out (~125 psi), cut-in (~100 psi), low-air warning (~60 psi) are all tested
- Confusing spring brakes (parking/emergency) with service brakes — which system does what, and when
- Forgetting the air-leak rate limits for the applied and released tests during inspection
- Assuming ABS changes how you brake — the test wants normal braking with ABS, not pumping
Studying with the full Truckcess course does double duty: the theory counts toward the federal ELDT requirement (Truckcess is listed on the FMCSA Training Provider Registry).
Official source: Vermont Department of Motor Vehicles
CDL licensing in Vermont is administered by the Vermont Department of Motor Vehicles. Fees, scheduling, forms, and the official Vermont CDL manual live on the official site: Vermont DMV — official CDL page (verified 2026-08-09).
Truckcess is not affiliated with or endorsed by the Vermont Department of Motor Vehicles. Our practice tests cover the federal CDL knowledge standards (49 CFR Part 383) that every state exam is built on; exact question counts, fees, and procedures vary by state and change over time — the official site is always the authority.
More Vermont practice tests
Full prep courses are one-time from $59 with 12 months of access — mytruckcess.com/cdl.
CDL practice tests by state · Meet the Course Director · The completion certificate