Inside the CDL Practice Pro Question Bank: 1,640 Questions, by the Numbers
We get asked what is actually inside CDL Practice Pro, so here are the real numbers, counted directly from the question bank on October 4, 2026. No estimates and no rounding up.
The headline number
The bank holds 1,640 active questions. Each one has a written explanation of the correct answer, and every explanation is available on the free plan. The median explanation is 26 words, so they are short: enough to name the rule and the reason, not a lecture.
Questions by knowledge test
These are the seven CDL knowledge tests the bank covers, with the number of active questions in each:
- General Knowledge: 506 questions. This is the test every applicant takes.
- Air Brakes: 254 questions.
- Combination Vehicles: 205 questions. Needed for Class A.
- Hazardous Materials (H): 205 questions. The endorsement also requires a TSA background check.
- School Bus (S): 165 questions.
- Passenger (P): 153 questions.
- Tanker (N): 152 questions.
General Knowledge is the largest by design. It is the one test that every CDL applicant must pass, and it covers the widest range of material.
Thirty-two topics, about fifty questions each
Inside those seven tests, every question is tagged to one of 32 topics, and most topics hold between 50 and 53 questions. The largest is stop procedures at 61. Others include vehicle inspection, space management, coupling and uncoupling, placarding, liquid surge, rollover prevention, dual air systems and emergency exit handling.
That tagging matters for studying. If you keep missing air brake questions, you can see whether the problem is the inspection routine, how the dual air system works, or what the brake parts do, and practice that one topic instead of re-reading the whole manual.
Difficulty
Questions are rated 1 to 3. Of the 1,640, 602 are rated 1, 800 are rated 2, and 238 are rated 3. In other words, about half sit in the middle, and a little under a sixth are the hardest tier.
Languages
Every question exists in English. Spanish versions cover 1,635 questions and Chinese versions cover 1,634. The Spanish and Chinese interfaces are still only partly translated, which is why the site's English pages are the ones we ask search engines to index.
What the bank is not
Two limits worth stating plainly:
- The questions are not state-specific. They cover the federal-standard topics that every state's knowledge test draws on. Your state sets its own fees, scheduling and extra rules, so each of our state pages links to the official licensing agency.
- They are not the real test. Actual exam questions are confidential. This is a practice tool, and passing the real test takes 80% on each knowledge test under 49 CFR 383.135.
How to use it
Start with the free CDL practice test page, which explains what the free plan includes: 10 new questions a day across every category, with explanations. Take the readiness check first if you are unsure where you stand, then work on the topics where you score lowest.
Counts reflect active questions in the CDL Practice Pro database as of October 4, 2026, and will change as questions are added or reviewed.