What's the Passing Score on the Missouri CDL General Knowledge Test?
You need about 80% on Missouri's CDL General Knowledge test — and on the Air Brakes and Combination Vehicles tests too, if your license class requires them. That figure comes from federal regulation, not the DOR.
One standard, three separate tests
49 CFR Part 383 sets the roughly 80% passing standard nationwide for CDL knowledge testing, independent of which specific tests a given applicant needs to take.
A missed attempt costs more than just your time — Missouri's CLP costs $44, and rescheduling a retest means another trip to a Highway Patrol driver examination station.
Building in a safety margin
Treat 80% as a floor, not a target — aim for 90%+ on each required test in practice, since real testing conditions under time pressure tend to run a few points below your practice average.
Our practice tests break your score down by topic immediately after each set, so a weak spot doesn't stay hidden inside an otherwise decent overall percentage.
The parts of the test that pull scores down
Air brake systems and hours-of-service limits are common trouble spots, since both hinge on exact numbers (PSI thresholds, hour caps) rather than driving intuition.
Cargo securement sequencing is another frequent miss — remembering that the first check happens within 50 miles, then every 150 miles or 3 hours after, is easy to get backwards under pressure.
Read the explanation on every practice question, correct or not — it's what actually closes these gaps, not just re-answering until you get lucky.
Frequently Asked Questions
Can Missouri require a higher passing score than the federal minimum?
No. 49 CFR Part 383 fixes the roughly 80% passing threshold nationwide for CDL knowledge testing — the DOR and Highway Patrol administer that federal standard rather than setting their own.
Do the Air Brakes and Combination Vehicles tests use the same passing score?
Yes — all three tests use roughly the same 80% standard, though each is scored and passed independently.
What score should I aim for on practice tests?
Aim for 90% or higher consistently before your appointment. That buffer accounts for first-attempt nerves and any last-minute rule changes.
Ready to put this into practice?
Start a free Missouri cdl practice testLast reviewed: 2026-07-21