Free, full Ohio 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 BMV knowledge exam.
According to federal regulations, you must inspect your cargo within the first ____ miles of your trip.
C. 25 miles — You must check your cargo and securing devices within the first 25 miles of starting your trip, then every 150 miles or 3 hours thereafter.
What is the minimum eyesight requirement to qualify for a CDL under 49 CFR Part 391?
B. At least 20/40 vision in each eye (with or without correction) and adequate field of vision — CDL applicants must have at least 20/40 acuity in each eye separately, with or without corrective lenses, and a field of vision of at least 70 degrees in the horizontal meridian in each eye.
What should you do if you find a defect on your vehicle during a pre-trip that makes the vehicle unsafe to operate?
B. Correct the defect before operating the vehicle, or report it to your supervisor and wait for authorization or repair — you may not drive an unsafe vehicle — If a pre-trip inspection reveals a defect that makes the vehicle unsafe, you must not drive the vehicle. Report it immediately to your supervisor and wait for the defect to be repaired before operating.
What is the function of the relay valve in an air brake system?
A. To speed up apply and release of rear brakes — Relay valves speed up air delivery to the trailer brakes. Without them, there would be excessive brake lag.
Reaction distance is the distance your vehicle travels:
C. From when your brain recognizes a hazard until your foot pushes the brake — Reaction distance covers the roughly three-quarters of a second between recognizing danger and moving your foot to the brake pedal.
What is a 'converter dolly' used for?
B. To connect a second semitrailer to a lead trailer, forming a double combination — A converter dolly is a set of one or two axles with a fifth wheel, used to convert a semitrailer into a full trailer. It connects two trailers to make a double (B-train) combination.
When checking the engine compartment during a pre-trip, the engine should be:
A. Off, with the parking brake on and wheels chocked — Checking the engine compartment with the engine off, brake set, and wheels chocked keeps you safe from moving belts and accidental rolling.
What is the primary hazard of a partially filled tanker compared to a full or empty tanker?
B. More liquid surge due to free liquid movement in the tank — A partially filled tanker has free liquid that can surge violently. A full tank has no room to surge, and an empty tank has no liquid. The half-full condition is most dangerous.
What is the safe following distance for commercial vehicles?
B. At least one second per 10 feet of vehicle length — Follow the formula: one second for each 10 feet of vehicle length at speeds below 40 mph, plus one extra second above 40 mph.
When driving a tanker through an on-ramp or off-ramp curve, you should:
A. Slow to well below the posted ramp speed because of the high rollover risk — Ramp speeds are set for ordinary vehicles, so a top-heavy tanker should enter well below them to avoid rolling over.
The Ohio 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 Ohio, driver licensing is handled by the Bureau of Motor Vehicles (BMV), so you'll often see the exam called the BMV CDL general knowledge test. The practice tests on this page match the official BMV 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.