CDL Combination Vehicles Practice Test
The Combination Vehicles knowledge test is required for every Class A CDL applicant — the license you need to legally pull a tractor-trailer, a car-hauler, or any combination where the towed vehicle weighs more than 10,000 lb. It's not an optional endorsement; without it you cannot get a Class A CDL.
This free practice test walks you through everything the DMV covers: driving safely with a trailer, coupling and uncoupling procedures, inspecting the fifth wheel and kingpin, and handling the unique control challenges (off-tracking, rearward amplification, trailer skids) that come with pulling a load.
What this test covers
- Driving combination vehicles safely
- Coupling and uncoupling tractor-trailers step by step
- Fifth wheel, kingpin, and locking jaw inspection
- Inspecting a combination vehicle (added pre-trip items)
- Off-tracking and turning wide
- Rearward amplification and trailer sway
- Trailer skid recovery
How to study
- Learn the coupling and uncoupling steps in order — the DMV can ask you to identify what comes next in the sequence.
- Understand rearward amplification: a car hauler with double or triple trailers reacts faster than a single, and that changes how you steer.
- Pair this section with Air Brakes practice — nearly every Class A vehicle has both.
Frequently asked questions
- Is the Combination Vehicles test only for Class A?
- Yes. Class A CDL applicants must pass it. Class B drivers do not need it because Class B is a single unit over 26,000 lb without a heavy trailer.
- How many questions are on the Combination Vehicles test?
- Most states give a 20-question Combination Vehicles knowledge test and require 80% (16 out of 20) to pass. Wording and count can vary slightly by state.
- Do I need Air Brakes and Combination Vehicles together?
- Almost always. Nearly every Class A tractor-trailer uses air brakes, so most Class A applicants take General Knowledge, Air Brakes, and Combination Vehicles as a set.
Ready to start?
Practice this CDL topic free — no account needed for your first session. Unlock the full course when you're ready.