Missouri CDL Practice Test
Free, full Missouri CDL general knowledge test practice right here in your browser — 50 questions with a configured 80% practice threshold, diagnostic and adaptive modes, spaced-repetition review, and a readiness dashboard. No signup, no paywall — your progress is saved automatically on this device.
Missouri CDL requirements
| Minimum age (within the state) | 18 Federal floor for commercial driving within one state (49 CFR 383). A state may set a higher age. |
|---|---|
| Minimum age (across state lines) | 21 Required to drive commercially across state lines, or to haul hazardous materials at any distance. |
| Learner's permit hold | 14 days 49 CFR 383.25 — minimum time you must hold the commercial learner's permit before the skills test. No exceptions. |
| ELDT training required | Yes Entry-level driver training from an FMCSA Training Provider Registry provider is required for a first CDL, a Class B to Class A upgrade, and a first H, P or S endorsement. |
| HazMat renewal | 5 years Hazmat endorsement expires every 5 years; most states require the written test again plus a new TSA security threat assessment. |
Missouri source: Missouri Commercial Driver License Manual ↗. Fees and testing arrangements vary and change — confirm current figures with the agency.
The full CDL process, step by step → · Which endorsements you need →
Primary study source: Missouri Commercial Driver License Manual ↗. Always confirm state-specific licensing rules with DOR.
Sample Missouri CDL general knowledge test questions
What is the maximum BAC allowed for CDL holders operating a commercial vehicle?
- A. 0.04%
- B. 0.08%
- C. 0.02%
- D. 0.00%
Show answer
A. 0.04% — CDL holders face a stricter 0.04% BAC limit because commercial vehicles are heavier and harder to stop, making impairment far more dangerous. Even at 0.04% a driver can be charged with DUI regardless of how they feel.
Universal rule · checked against 49 CFR § 392.5 — Alcohol prohibition and 0.04 BAC standard for drivers on duty · verified 2026-05-17
What are the three emergency equipment items required on commercial vehicles?
- A. Fire extinguisher, spare fuses, warning triangles
- B. First aid kit, flares, flashlight
- C. Jack, tire iron, jumper cables
- D. Tow strap, shovel, ice scraper
Show answer
A. Fire extinguisher, spare fuses, warning triangles — Federal law requires all commercial motor vehicles to carry a fire extinguisher of the correct type and rating, a set of three reflective warning triangles, and spare electrical fuses — missing any item is an out-of-service violation.
Universal rule · checked against 49 CFR § 393.95 — Emergency equipment on commercial motor vehicles · verified 2026-05-17
How often should you check your mirrors while driving a commercial vehicle?
- A. Every 30 seconds
- B. Every minute
- C. Every 5-8 seconds
- D. Only when changing lanes
Show answer
C. Every 5-8 seconds — Check mirrors every 5-8 seconds to maintain awareness of your surroundings and traffic conditions.
Universal rule · checked against FMCSA Commercial Driver License Manual — Section 2: Driving Safely · verified 2026-05-17
At what PSI does the low air pressure warning usually activate?
- A. 40 PSI
- B. 60 PSI
- C. 50 PSI
- D. 70 PSI
Show answer
B. 60 PSI — The low air pressure warning signal must come on before air pressure drops below 60 PSI.
Universal rule · checked against FMCSA Commercial Driver License Manual — Section 5: Air Brakes · verified 2026-05-17
During the engine compartment check, you should verify the alternator belt is:
- A. Any color
- B. Made of rubber only
- C. Not cracked, frayed, or too loose/tight
- D. Connected to the air compressor
Show answer
C. Not cracked, frayed, or too loose/tight — Check the alternator/serpentine belt for cracks, fraying, and proper tension. A broken belt causes charging and cooling system failure.
Universal rule · checked against FMCSA Commercial Driver License Manual — Section 11: Vehicle Inspection Test · verified 2026-05-17
Questions last verified 2026-05-17 · Reviewed by the DMV Prep editorial team · Editorial policy
Frequently asked questions
How many questions are in this Missouri CDL general knowledge test practice test?
This practice test uses 50 questions and a 80% study target — at least 40 correct answers. Confirm the current official exam format with the state licensing agency. CDL content here focuses on the federal general-knowledge core; endorsements and vendor formats can vary.
What score should I target for the Missouri CDL general knowledge test?
Use 80% as the practice target on this site. The readiness dashboard tracks consistent performance; the state agency remains the source for current official requirements.
Is the Missouri CDL general knowledge test taken at the DMV?
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. Confirm the current official format with DOR; this page uses DMV Prep's recorded practice configuration.
Is this Missouri CDL general knowledge test practice really free?
Yes. Every practice test on this page and everything in the DMV Prep app is free — no ads, no paywall, no account.
Where do these CDL general knowledge test questions come from?
Questions use Missouri Commercial Driver License Manual and applicable licensing references. Citation scope and recency are being revalidated across the bank.
Can I study for the Missouri CDL general knowledge test in Spanish?
Yes — the DMV Prep app includes all 3,671+ questions in Spanish, and the whole app works in Spanish.
