CDL Exam FAQ

A CDL (Commercial Driver's License) is a driver's license required to operate large, heavy, or hazardous material vehicles in commerce in the United States. CDLs are classified as Class A, Class B, or Class C depending on the type and weight of vehicle. The Federal Motor Carrier Safety Administration (FMCSA) sets minimum CDL standards that all states must follow.

The minimum age for an intrastate CDL (operating within one state only) is 18 years old. For interstate commerce (crossing state lines), the federal minimum is 21 years old. Check your state's DMV for specific rules.

Class A: Any combination of vehicles with a Gross Combination Weight Rating (GCWR) of 26,001+ lbs, where the towed vehicle exceeds 10,000 lbs. Includes tractor-trailers, semis, flatbeds, and lowboys.

Class B: Single vehicles with a GVWR of 26,001+ lbs. Includes straight trucks, large buses, dump trucks, and delivery vehicles. Class A holders can also drive Class B vehicles.

Class C: Vehicles not covered by A or B that transport 16+ passengers or hazardous materials requiring placards. Includes small HazMat vehicles and large vans.

It depends on the weight. Box trucks (straight trucks) with a GVWR over 26,000 pounds require a Class B CDL. Smaller box trucks under 26,001 lbs GVWR typically do not require a CDL. If the box truck is used to transport hazardous materials requiring placards, a Class C CDL with Hazmat endorsement may be required regardless of weight.

Federal disqualifications include: conviction for using a CMV in a felony, DUI in a CMV or personal vehicle, leaving the scene of an accident, serious traffic violations (two within 3 years), and certain medical conditions. The Hazmat endorsement requires passing a TSA security threat assessment, which checks criminal history. Some prior convictions, especially related to terrorism, automatically disqualify applicants.

General Knowledge: 50 questions (40 correct = 80% to pass)
Air Brakes: 25 questions (20 correct = 80% to pass)
Combination Vehicles: 20 questions
Hazmat: 30 questions (24 correct = 80% to pass)
Tanker: 20 questions
Passenger: 20 questions
School Bus: 20 questions
Doubles/Triples: 20 questions
All endorsement tests require 80% to pass.

If you fail, you can typically retake the test after a waiting period set by your state (usually 24 hours to 2 weeks). Most states limit the number of attempts before you must wait longer or pay additional fees. Use CDL Pass USA's free practice tests to identify weak areas before retesting.

The Air Brakes test is not required for all CDL applicants — however, if you don't pass it or don't take it, your CDL will have an Air Brakes restriction, meaning you cannot operate vehicles with air brakes. Since most commercial vehicles have air brakes, it is highly recommended to take and pass the Air Brakes test.

H — Hazmat: Transport hazardous materials requiring placards
N — Tanker: Operate tank vehicles with 1,000+ gallon capacity
P — Passenger: Drive vehicles with 16+ passengers
S — School Bus: Drive school buses (also requires P endorsement)
T — Doubles/Triples: Pull more than one trailer (Class A only)
X — Hazmat + Tanker: Combination endorsement for hazmat tankers

Which endorsements you need depends on your job. Truck drivers often need H and/or N. Bus drivers need P. School bus drivers need P and S.

1. Meet your state's eligibility requirements (age, residency, medical)
2. Get a DOT physical exam and receive your Medical Examiner's Certificate
3. Study the CDL manual for your state
4. Take and pass the CDL knowledge tests at your state DMV to get your CDL Learner's Permit (CLP)
5. Hold your CLP for at least 14 days before taking skills tests
6. Complete CDL training at an FMCSA-registered school (required under ELDT rules)
7. Pass the CDL skills test (pre-trip inspection, basic vehicle control, road test)
8. Receive your CDL

Entry-level CDL training typically takes 3 to 7 weeks at an accredited program. The full process from starting school to receiving your CDL (including testing and waiting periods) usually takes 4 to 8 weeks. Sponsored training programs through trucking companies may move faster.

CDL school tuition: $1,000–$10,000 depending on program
Sponsored programs: $0 upfront (company pays in exchange for work commitment)
DOT physical: $75–$150
State DMV fees: $50–$200 for tests and license
Hazmat TSA background check: ~$86

Total out-of-pocket (self-pay) typically ranges from $2,000 to $12,000. Sponsored programs through carriers can reduce this to near zero.

The Entry-Level Driver Training (ELDT) rule, effective February 7, 2022, requires all first-time CDL applicants to complete training from an FMCSA-registered school before taking their CDL skills test. This applies to Class A and B CDL applicants and those seeking Passenger, School Bus, or Hazmat endorsements. Self-study alone is no longer sufficient for skills testing.

1. Read your state's CDL manual — most DMVs publish it free online
2. Take CDL practice tests — CDL Pass USA offers free practice tests for all topics
3. Identify weak areas — focus study time on topics you're missing
4. Repeat practice tests — aim for 90%+ before the real test
5. Use the CDL Pass app — study anywhere on your phone
Most students need 2–4 weeks of consistent study to feel prepared.

CDL practice tests like those on CDL Pass USA are modeled after the actual CDL knowledge test content — they cover the same topics and question types. However, the exact questions on the real test will differ. Practicing with many different questions builds the knowledge needed to answer any question the DMV might ask on a given topic.

CDL Pass USA offers full Spanish-language CDL practice tests at cdlpassusa.com/cdl-pass-es. The CDL Pass mobile app also includes full Spanish support. Most state DMVs also offer the CDL knowledge test in Spanish — contact your state DMV to confirm availability.