Straight answers. Primary sources.
23 questions, answered. Every one starts with the answer — no wind-up — and every factual claim links to the federal rule or official dataset behind it. Written by Travis Stuckert, a 15-year Class A CDL driver. New questions ship in verified batches; this hub grows.
These are the federal rules, which are the floor. States add their own requirements on top — where that matters most, the answer says so.
Getting Your CDL
The process, the permit, the training, the tests.
How do I get a CDL?
To get a CDL, you pass your state's knowledge tests for a commercial learner's permit (CLP), complete Entry-Level Driver Training from a provider on the federal Training Provider Registry, hold the CLP at least 14 days, then pass the three-part skills test. Your state issues the license.
Read the full answer to: How do I get a CDL?Last verified against primary sources: July 22, 2026Report a mistake in the answer to: How do I get a CDL?What's the difference between a CLP and a CDL?
A commercial learner's permit (CLP) is the supervised learning stage: it lets you drive a commercial vehicle only with a qualified CDL holder beside you. A CDL is the full license. Federal law requires you to hold the CLP at least 14 days before taking the CDL skills test.
Read the full answer to: What's the difference between a CLP and a CDL?Last verified against primary sources: July 22, 2026Report a mistake in the answer to: What's the difference between a CLP and a CDL?How much does CDL school cost — and how can I pay for it?
There's no single national price for CDL school — each program sets its own tuition, and federal training rules set no minimum hours. Sampled Ohio Class A programs published $4,995–$7,165.20 (July 2026). Eligible applicants can get training covered through WIOA funds, and some carriers run their own registered training programs.
Read the full answer to: How much does CDL school cost — and how can I pay for it?Last verified against primary sources: July 22, 2026Report a mistake in the answer to: How much does CDL school cost — and how can I pay for it?How long is a CLP valid before it expires?
Federal rules permit a CLP to remain valid for no more than one year from initial issuance without retaking the knowledge tests. A state may issue it for a shorter period.
Source: 49 CFR §383.25(c) — source for: How long is a CLP valid before it expires?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: How long is a CLP valid before it expires?How long must you hold a CLP before taking the skills test?
A CLP holder is not eligible to take the CDL skills test during the first 14 days after the permit's initial issuance.
Source: 49 CFR §383.25(e) — source for: How long must you hold a CLP before taking the skills test?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: How long must you hold a CLP before taking the skills test?What is ELDT and who must complete it?
Entry-Level Driver Training is federally required training for someone obtaining a Class A or B CDL for the first time, upgrading Class B to A, or obtaining a P, S, or H endorsement for the first time. Training must be completed through a registered provider before the applicable skills test (or the H knowledge test), unless an exemption applies. Credentials obtained before February 7, 2022 are not retroactively subject to ELDT.
Sources: 49 CFR §380.603 (ELDT applicability) — source for: What is ELDT and who must complete it?FMCSA — Entry-Level Driver Training — source for: What is ELDT and who must complete it?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: What is ELDT and who must complete it?How do you find an FMCSA-registered training provider?
Use FMCSA's Training Provider Registry, searchable by training type, location, or provider name. Required ELDT must be completed with a provider listed there.
Sources: FMCSA Training Provider Registry — selecting a provider — source for: How do you find an FMCSA-registered training provider?FMCSA Training Provider Registry — provider search — source for: How do you find an FMCSA-registered training provider?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: How do you find an FMCSA-registered training provider?What's the passing score on the CDL knowledge test?
An applicant must answer at least 80% of the questions correctly on each CDL knowledge test — this applies separately to the general knowledge test and each endorsement test.
Source: 49 CFR §383.135(a) — source for: What's the passing score on the CDL knowledge test?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: What's the passing score on the CDL knowledge test?What's tested in the pre-trip inspection?
The applicant must identify safety-related parts and explain how to determine whether they're safe — engine compartment, cab, steering, suspension, brakes, wheels, and vehicle-specific features. Air-brake vehicles also require identifying and testing the air-brake controls, warning devices, pressure buildup, and connections.
Source: 49 CFR §383.113(a) — source for: What's tested in the pre-trip inspection?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: What's tested in the pre-trip inspection?What happens if you fail the skills test — what are the retest rules?
Federal rules require passing each skills-test segment and mandate automatic failure for conduct like disobeying traffic laws or causing an accident during the test. There is no uniform federal waiting period, fee, or maximum number of attempts — states administer their own tests and set their own retest procedures.
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: What happens if you fail the skills test — what are the retest rules?Can you transfer a CDL between states?
Yes. After establishing domicile in a new state, the driver must apply there within 30 days, surrender the old-state CDL, and provide the required history and domicile documents. Retaining a hazardous-materials endorsement requires separately satisfying TSA and state requirements.
Source: 49 CFR §383.71(c) — source for: Can you transfer a CDL between states?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: Can you transfer a CDL between states?
Classes, Endorsements & Restrictions
What each license covers, and what the letters on it mean.
What are CDL classes A, B, and C?
Class A covers combinations rated at least 26,001 lbs when the towed unit exceeds 10,000 lbs. Class B covers a single vehicle rated at least 26,001 lbs, including one towing a vehicle of 10,000 lbs or less. Class C covers vehicles outside A and B that carry at least 16 people including the driver, or qualifying hazardous materials.
Source: 49 CFR §383.91 (commercial motor vehicle groups) — source for: What are CDL classes A, B, and C?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: What are CDL classes A, B, and C?What do endorsements H, N, T, P, S, and X mean?
H = hazardous materials, N = tank vehicle, T = double/triple trailers, P = passenger, S = school bus, X = combined tank-and-hazmat. H, N, T, and X require knowledge testing only; P and S require both knowledge and skills testing.
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: What do endorsements H, N, T, P, S, and X mean?How does the Hazmat endorsement background check work?
The applicant submits identifying information and fingerprints through the state or TSA enrollment process. TSA conducts criminal-history, immigration, and terrorism checks and sends the state a “Determination of No Security Threat.” The state cannot issue, renew, upgrade, or transfer the endorsement without it. The assessment normally remains valid for five years.
Sources: 49 CFR §1572.13 (TSA security threat assessment) — source for: How does the Hazmat endorsement background check work?FMCSA — hazmat endorsement limitations — source for: How does the Hazmat endorsement background check work?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: How does the Hazmat endorsement background check work?
Pay & Jobs
What driving actually pays, from official data.
How much do truck drivers make?
Heavy and tractor-trailer truck drivers in the U.S. earned a median $58,640 per year ($28.19 per hour) as of the Bureau of Labor Statistics' May 2025 survey. The lowest-paid ten percent earned under $40,140, the highest-paid ten percent over $79,380. It's a national baseline, not a first-year promise.
Read the full answer to: How much do truck drivers make?Last verified against primary sources: July 22, 2026Report a mistake in the answer to: How much do truck drivers make?
Eligibility & Disqualifications
What stops a CDL — and what doesn't.
What disqualifies you from getting a CDL?
Federal rule 49 CFR §383.51 lists the disqualifying offenses: major offenses like DUI carry a one-year disqualification for a first conviction and lifetime for a second; "serious traffic violations" disqualify only when repeated. A personal-vehicle DUI counts for permit and license holders. Drug-and-alcohol violations block licensing until return-to-duty is complete.
Read the full answer to: What disqualifies you from getting a CDL?Last verified against primary sources: July 22, 2026Report a mistake in the answer to: What disqualifies you from getting a CDL?What's the minimum age for a CDL — interstate vs. intrastate?
A driver generally must be at least 21 to operate a commercial motor vehicle in interstate commerce. Federal rules permit CLPs and CDLs beginning at 18 for intrastate-only operation, though states may set stricter requirements. A narrow federal pilot program (the Safe Driver Apprenticeship Pilot) allows a limited number of specially-trained 18–20 year-olds to drive interstate under strict conditions — it is not the general rule.
Sources: 49 CFR §391.11(b)(1) — source for: What's the minimum age for a CDL — interstate vs. intrastate?FMCSA — Safe Driver Apprenticeship Pilot Program FAQ — source for: What's the minimum age for a CDL — interstate vs. intrastate?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: What's the minimum age for a CDL — interstate vs. intrastate?Can a DUI in a personal vehicle disqualify a CDL?
Yes. For a CDL or CLP holder, a first state-law DUI conviction in a non-commercial vehicle generally causes a one-year CMV disqualification; a second separate major-offense conviction can result in lifetime disqualification.
Source: 49 CFR §383.51(a)(3) and Table 1 — source for: Can a DUI in a personal vehicle disqualify a CDL?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: Can a DUI in a personal vehicle disqualify a CDL?Is insulin-treated diabetes disqualifying?
No — not automatically. A driver may qualify if the treating clinician completes Form MCSA-5870, the diabetes is properly controlled on a stable insulin regimen, and an FMCSA-certified medical examiner approves the driver. Certification is generally limited to 12 months; certain severe diabetic retinopathy is permanently disqualifying.
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: Is insulin-treated diabetes disqualifying?What does the DOT physical check, and how long is the medical card valid?
The exam covers medical history, vision, hearing, blood pressure and pulse, urinalysis, and physical systems including cardiovascular, respiratory, neurological, musculoskeletal, and spine. A medical certificate is valid for up to 24 months, though the examiner may issue a shorter certificate if a condition requires monitoring.
Sources: 49 CFR §391.43 (medical examination; certificate) — source for: What does the DOT physical check, and how long is the medical card valid?FMCSA — DOT medical exam and CMV certification — source for: What does the DOT physical check, and how long is the medical card valid?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: What does the DOT physical check, and how long is the medical card valid?
Rules of the Job
Hours, logs, and the federal databases that follow you.
What are the current hours-of-service limits?
Property-carrying drivers generally may drive 11 hours after 10 consecutive hours off duty, may not drive after the 14th consecutive hour after coming on duty, need a 30-minute break after 8 cumulative driving hours, and are subject to 60/70-hour limits over 7/8 days. Passenger-carrying drivers have a 10-hour driving limit and a 15-hour on-duty limit, with the same 60/70-hour rule. Exceptions exist for sleeper berth use, adverse conditions, and short-haul operations.
Sources: FMCSA — Summary of Hours of Service Regulations — source for: What are the current hours-of-service limits?49 CFR §395.3 (property-carrying vehicles) — source for: What are the current hours-of-service limits?49 CFR §395.5 (passenger-carrying vehicles) — source for: What are the current hours-of-service limits?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: What are the current hours-of-service limits?Who must use an ELD, and what are the exemptions?
The ELD requirement generally applies to carriers and drivers required to maintain records of duty status. Exemptions include short-haul/timecard drivers, drivers needing records of duty status no more than 8 days in any 30-day period, qualifying driveaway-towaway operations, and vehicles with an engine model year before 2000. Some exempt drivers must still keep paper logs.
Sources: FMCSA — ELD Fact Sheet — source for: Who must use an ELD, and what are the exemptions?FMCSA — ELD exemptions FAQ — source for: Who must use an ELD, and what are the exemptions?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: Who must use an ELD, and what are the exemptions?What is the Drug & Alcohol Clearinghouse, and who must register?
The Clearinghouse is FMCSA's database of CDL/CLP drivers' drug-and-alcohol violations and return-to-duty status. Employers must query it before hiring and at least annually. Employers, medical review officers, substance abuse professionals, and consortium administrators must register to perform their functions. Drivers must register to consent electronically to a full query or view their own record.
Sources: 49 CFR §382.701 (Clearinghouse queries) — source for: What is the Drug & Alcohol Clearinghouse, and who must register?FMCSA Clearinghouse — employer and registration FAQ — source for: What is the Drug & Alcohol Clearinghouse, and who must register?
Last verified against primary sources: July 27, 2026Report a mistake in the answer to: What is the Drug & Alcohol Clearinghouse, and who must register?
Done reading? Start practicing.
The knowledge tests are the first real step to a CLP — practice them free, question by question, every answer cited to the official manual.