CDL general knowledge
Every commercial driver starts with the general knowledge test. It covers the federal rules drivers live by (hours of service, inspections, disqualifications), vehicle control, space and speed management, hazards, emergencies, cargo and railroad crossings.
Federal law requires a commercial driver's license to drive a commercial motor vehicle, and every CDL applicant must pass the general knowledge test first. 49 CFR 383.23 (Commercial driver's license required) and 383.111 (Required knowledge).
Practice and timed mocks are free, with right or wrong on every answer and your total score. The full analysis is $39, once.
How the exam is built
Owned by Federal Motor Carrier Safety Administration (standards); state licensing agencies (tests).
General knowledge test
50 scored questions, to pass: 80% of scored questions right.
| Topic | Share |
|---|---|
| Safe operations regulations (hours of service, disqualification, electronic devices, entry-level training) | 13% |
| Vehicle inspections and safety control systems | 14% |
| Basic control, shifting, and backing | 6% |
| Visual search and communication | 8% |
| Speed management and space management | 12% |
| Hazard perception | 6% |
| Night operation, extreme driving conditions, and mountain driving | 10% |
| Emergency maneuvers, skid control, crashes, and fires | 11% |
| Relationship of cargo to vehicle control | 7% |
| Railroad-highway grade crossings | 5% |
| Alcohol, drugs, fatigue, and fitness to drive | 5% |
| Hazardous materials rules for all drivers | 3% |
The official outline: www.ecfr.gov/api/renderer/v1/content/enhanced/current/title-49?part=383§ion=383.111. Checked 2026-10-08.
Sources
- FMCSA required knowledge for the CDL general knowledge test, 49 CFR 383.111(a)(1) to (20), with testing standards in 383.133 and 383.135 (eCFR current as of 2026-10-07); content as taught in state CDL manuals (New York CDL-10, Sections 1 rev. 2/26, 2 and 3 rev. 11/25), retrieved 2026-10-08.
- Exam format and pass rule, retrieved 2026-10-08.
Questions are original, written from the official outline and primary sources under an assessment framework designed by Julian Calvo, Ed.D., M.S. DecipherU is not affiliated with FMCSA or any state licensing agency. Every practice question is original and written from federal regulations and official state CDL manuals.