District of Columbia CDL Practice Test
Free, full District of Columbia 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.
District of Columbia 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. |
District of Columbia source: DC DMV Commercial Driver License ↗. 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: DC DMV Commercial Driver License ↗. Always confirm state-specific licensing rules with your state licensing agency.
Sample District of Columbia CDL general knowledge test questions
An ELD (Electronic Logging Device) is required for:
- A. Most CMV drivers who must keep duty status records
- B. All passenger cars, regardless of commercial use
- C. Hazmat carriers
- D. Owner-operators
Show answer
A. Most CMV drivers who must keep duty status records — Most CMV drivers who must maintain records of duty status are required to use an ELD to track hours of service electronically.
Universal rule · checked against 49 CFR Part 395 — Electronic logging device and hours of service records · verified 2026-05-17
Cargo that is loaded improperly can cause:
- A. Better fuel economy from a lower center of gravity
- B. Faster delivery times
- C. The vehicle to tip over or handling problems
- D. Reduced tire wear
Show answer
C. The vehicle to tip over or handling problems — Improperly loaded or unbalanced cargo can cause rollovers, poor handling, axle damage, or brake problems.
Universal rule · checked against FMCSA Commercial Driver License Manual — Section 3: Transporting Cargo Safely · verified 2026-05-17
If your vehicle catches fire, the first thing you should do is:
- A. Pull off the road, shut off the engine, and get away from the vehicle
- B. Use the CB radio first before taking any other action
- C. Open the hood to check
- D. Keep driving to a fire station
Show answer
A. Pull off the road, shut off the engine, and get away from the vehicle — Pull over safely, shut off the engine, grab your fire extinguisher if safe to use, and get away from the vehicle. Call 911.
Universal rule · checked against FMCSA Commercial Driver License Manual — Section 2: Emergencies · verified 2026-05-17
During the walk-around inspection, you should check that all lug nuts are:
- A. Painted brightly for visibility at night
- B. Present, not cracked, and not showing rust streaks from looseness
- C. Made of aluminum
- D. Covered with hub caps
Show answer
B. Present, not cracked, and not showing rust streaks from looseness — Check that all lug nuts are present, tight, and not cracked. Rust streaks can indicate loose nuts. Missing or damaged lugs are out-of-service conditions.
Universal rule · checked against 49 CFR Part 177 — Carriage by public highway - hazardous materials loading and transport · verified 2026-05-17
The trailer supply valve (red octagonal knob) controls:
- A. The tractor engine
- B. Air supply to the trailer
- C. The fuel supply
- D. Window defrosters
Show answer
B. Air supply to the trailer — The trailer supply valve (red octagonal knob) controls the air supply from the tractor to the trailer brake system.
Universal rule · checked against FMCSA Commercial Driver License Manual — Section 6: Combination Vehicles · 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 District of Columbia 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 District of Columbia 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 this District of Columbia 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 DC DMV Commercial Driver License and applicable licensing references. Citation scope and recency are being revalidated across the bank.
Can I study for the District of Columbia 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.
