CDL Guide
Your complete guide to getting a Commercial Driver's License. CDL class A vs B vs C, the step-by-step process, DOT physical, skills test, and everything in between.
CDL Classes: A, B, and C
Combination Vehicles
Examples: Tractor-trailers (semis), tankers, flatbeds, lowboys, doubles, triples, livestock carriers
Threshold: Towing vehicle >26,001 lbs AND towed vehicle >10,000 lbs
Min. Age: 18 (intrastate) / 21 (interstate)
Large Single Vehicles
Examples: Straight trucks, dump trucks, city buses, transit buses, concrete mixers, delivery trucks
Threshold: Single vehicle >26,001 lbs (or towing <10,000 lbs)
Min. Age: 18 (intrastate) / 21 (interstate)
Specialized Small Vehicles
Examples: Vehicles for 16+ passengers (not requiring Class B), hazmat vehicles below A/B thresholds
Threshold: Below Class A/B thresholds but requires special operation
Min. Age: 18 (intrastate) / 21 (interstate)
How to Get Your CDL — Step by Step
Pass the DOT Physical
Visit a FMCSA-certified medical examiner. You must have adequate vision (with or without correction), hearing, and blood pressure within acceptable ranges. You'll receive a medical examiner's certificate valid for 2 years (shorter if you have certain medical conditions).
Pass CDL Knowledge Tests
Pass the CDL General Knowledge test at your state DMV (100 questions, 80% to pass). If you want endorsements like Air Brakes or Hazmat, take those tests at the same visit. Passing issues you a Commercial Learner's Permit (CLP).
Hold the CLP for 14 Days
Federal law requires you to hold the CLP for at least 14 calendar days before taking the skills test. Use this time to practice with a CDL holder riding with you.
Pass the CDL Skills Test
The CDL skills test has three parts: pre-trip vehicle inspection (identify components and potential defects), basic vehicle control (straight-line backing, offset backing, alley dock), and on-road driving (15-30 minutes on public roads with an examiner).
Receive Your CDL
After passing the skills test, the DMV issues your CDL with the appropriate class. If you completed the Hazmat endorsement, you still need to pass the TSA background check before the H endorsement is added.
CDL Endorsements Overview
| Code | Name | Required For | Questions |
|---|---|---|---|
| H | Hazardous Materials | Transporting hazmat requiring placards | 30 |
| N | Tanker | Tank vehicles ≥1,000 gallons | 25 |
| P | Passenger | Vehicles with 16+ passengers | 20 |
| S | School Bus | School buses (also requires P) | 20 |
| T | Doubles/Triples | Pulling double or triple trailers | 20 |
| X | Hazmat + Tanker | Combined H and N endorsement | Combined |
Frequently Asked Questions
What is the highest CDL class?
Class A is the highest CDL class. A Class A CDL qualifies you to drive combination vehicles (tractor-trailers, doubles, triples, tankers, flatbeds, and lowboys) where the towing vehicle weighs over 26,001 lbs and the towed vehicle exceeds 10,000 lbs. Class A holders may also drive Class B and C vehicles.
Do you need a DOT physical to get a CDL?
Yes. To obtain a CDL, you must pass a Department of Transportation (DOT) physical examination performed by a licensed medical examiner listed on the FMCSA National Registry. The physical evaluates vision, hearing, blood pressure, neurological function, and other health factors. A valid medical certificate (typically good for 2 years) must be maintained throughout your CDL career.
How long does it take to get a CDL?
The CDL process typically takes 3 to 7 weeks for CDL school plus testing time. After passing the CDL knowledge tests, you must hold a Commercial Learner's Permit (CLP) for at least 14 days before taking the skills test. Full-time CDL training programs can have you licensed in 4-8 weeks total.
What disqualifies you from getting or keeping a CDL?
Major disqualifying offenses include: DUI conviction (1-year disqualification for first offense, lifetime ban for second), operating a CMV while impaired, refusing a blood alcohol test, causing a fatality through negligent CMV operation, and using a CMV in the commission of a felony. Losing your regular driver's license for 60 or more days also disqualifies you.
What endorsements are required?
The endorsements you need depend on what you drive. H (Hazmat) is required for hazardous materials, N (Tanker) for tank vehicles, P (Passenger) for 16+ passengers, S (School Bus) for school buses, T (Doubles/Triples) for pulling multiple trailers. Most truck drivers need only the CDL General Knowledge — endorsements are required for specialized operations.
Related Resources
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