Free, full Missouri CDL general knowledge test practice right here in your browser — real exam format (50 questions, 80% to pass), diagnostic and adaptive modes, spaced-repetition review, and a readiness dashboard. No signup, no paywall — your progress is saved automatically on this device. Matched to the official DOR knowledge exam.
Before starting down this long, steep grade in a heavy truck, you should:
B. Select a low gear before the descent and use light, intermittent braking — Choose a low gear before the grade so engine braking controls speed, using brief snub braking to avoid overheating the brakes.
Perception distance is:
B. The distance the vehicle travels from when you see a hazard until your brain recognizes it — Perception distance is how far you travel from spotting a hazard until your brain identifies it, and it adds to total stopping distance.
On a long downgrade, excessive use of service brakes can cause:
B. Brake fade from overheating — Continuous braking on a long downgrade overheats the brakes, causing brake fade — the brakes become less effective or fail entirely.
When transporting hazmat and parking temporarily, the vehicle must:
B. Be attended or parked in a safe, legal location — A loaded hazmat vehicle must be attended or parked in a designated safe area. Specific parking rules vary by class of material.
Your reaction time and judgment as a driver are first affected by fatigue when you:
D. Begin to feel drowsy, miss exits, or drift in your lane — Early fatigue shows as drifting, missed exits, and slowed reactions, so stop and rest before it becomes dangerous.
Under the 60/70-hour rule, a driver whose company operates every day of the week may not drive after being on duty:
D. 70 hours in any 8 consecutive days — If the carrier runs every day, a driver may not drive after 70 hours on duty in any 8 consecutive days until hours rebuild.
When driving in heavy traffic, the most important thing is to:
C. Maintain a safe following distance and stay alert — In heavy traffic, maintain your following distance and stay fully alert. Avoid unnecessary lane changes.
What should you check on the landing gear of a trailer during a vehicle inspection?
A. That it is retracted and the crank handle is secured — During inspection with the trailer coupled, landing gear must be fully retracted and the crank handle secured so it does not catch on anything during travel.
CDL safety scenario 9: During an en-route inspection, what should you check after the first 50 miles?
D. Cargo securement, tires, brakes, lights, and coupling devices — Cargo securement, tires, brakes, lights, and coupling devices. Commercial drivers are expected to manage this situation before it becomes a crash risk. The CDL manual emphasizes controlling the vehicle, inspecting safety-critical systems, and correcting hazards promptly.
At the end of a bus route or shift, the driver should:
B. Inspect the bus and report any defects or problems found during the day — A post-trip inspection and written report of any defects ensure the next driver gets a safe bus and problems get repaired.
The Missouri CDL general knowledge test has 50 questions, and you need 80% to pass — at least 40 correct answers. The practice tests on this page use the same format. The 80% passing score is a federal FMCSA standard used by every state.
80%. You can miss at most 10 of the 50 questions. The readiness dashboard on this page tracks whether you're consistently scoring above that bar.
In Missouri, driver licensing is handled by the Missouri Department of Revenue (DOR), so you'll often see the exam called the DOR CDL general knowledge test. The practice tests on this page match the official DOR knowledge exam format.
Yes. Every practice test on this page and everything in the DMVPrep iPhone app is free — no ads, no paywall, no account.
Federal motor carrier safety regulations (FMCSA) — the same rules every state's CDL exam is drawn from. Every question in the DMVPrep app cites the regulation or handbook section it comes from.
Yes — the DMVPrep app includes all 3,745+ questions in Spanish, and the whole app works in Spanish.