CDL Requirements: Age, Medical, Residency, and Eligibility

Quick answer: To qualify for a CDL you must meet the federal floor: be old enough (21 for interstate driving under 49 CFR 391.11; many states license 18–20-year-olds for intrastate-only driving), be medically qualified under 49 CFR 391.41, prove identity, lawful status, and state residency (49 CFR 383.71), hold only one license from one state (49 CFR 383.21), and be clear of the disqualifying offenses in 49 CFR 383.51.

Regulatory-change disclaimer: Last reviewed July 17, 2026. Federal requirements come from 49 CFR Parts 383 and 391; states can layer additional rules for intrastate drivers. Confirm current requirements with FMCSA and your state licensing agency before relying on this. Not legal advice.

The requirements at a glance

Think of eligibility as five gates, all federal, all checked before or during licensing: age, medical qualification, identity and residency, a clean-enough record, and one single license. States administer the checks and can add intrastate wrinkles, but they cannot lower the federal floor.

Who this applies to

Every applicant for a commercial learner's permit or CDL of any class, and every working CDL holder — the medical and disqualification rules keep applying for as long as you drive. If you're mapping the whole journey, start at the step-by-step guide.

Gate 1: age — the interstate/intrastate split

The number that matters is 21: federal driver-qualification rules (391.11(b)(1)) require interstate CMV drivers to be at least 21. States may issue CDLs to drivers 18–20, but those drivers are limited to intrastate work — loads and routes that never cross a state line or handle freight moving in interstate commerce. Practical consequence: most major carriers hire at 21, and an 18-year-old's first driving jobs are local and in-state. State rules on what 18–20-year-olds may haul vary — check yours.

Gate 2: medical qualification

You must meet the physical qualification standards of 391.41 — vision, hearing, blood pressure, and the condition-by-condition rules — demonstrated in an exam by a medical examiner on FMCSA's National Registry, who issues the medical examiner's certificate. When you apply, the state also has you self-certify your operating category (interstate vs intrastate, excepted vs non-excepted), which controls whether the medical certificate must be on file at all. The full picture — exam, certificate lengths, variances, and what happens when a card lapses — is in The DOT Medical Card. The examiner decides medical outcomes, not the school, not the carrier, and not this article.

Gate 3: identity, lawful status, and residency

Under 383.71 you prove who you are, that you're lawfully present in the U.S. (citizens and lawful permanent residents use the documents in the rule's proof table), and that you're domiciled in the state issuing the license. Bring originals — licensing agencies are strict about document lists, and the lists themselves are state-published. You must also surrender any other state's license: the one-driver/one-license rule in 383.21 is absolute, and holding two licenses is itself a violation.

Gate 4: the record — disqualifying offenses

49 CFR 383.51 is the disqualification engine. In outline:

• Major offenses — DUI in any vehicle (including a 0.04% or greater alcohol concentration in a CMV, or refusal to test), leaving the scene, using a vehicle to commit a felony, driving a CMV while your CDL is revoked, causing a fatality through negligent CMV operation. First offense: one year disqualified (three years if the vehicle was placarded for hazmat). Second: lifetime, with a possible reinstatement path after ten years at state discretion. Using a CMV in a felony involving controlled substances: lifetime, no reinstatement.
• Serious traffic violations — excessive speeding (15+ mph over), reckless driving, improper lane changes, following too closely, texting or hand-held phone use while driving a CMV, and more. Two convictions inside three years: 60 days; three or more: 120 days.
• Railroad-crossing violations and out-of-service violations carry their own escalating disqualifications.

These attach to the person, not the job — a DUI in your personal car counts against your CDL. That is the career risk 383.51 encodes, and why a clean record is an eligibility asset with a price on it.

Gate 5: the Clearinghouse

Since drug-and-alcohol testing went digital, your Clearinghouse status is effectively an eligibility requirement: carriers must query it before putting you in a truck, and a prohibited status stops employment until return-to-duty is complete. How the database, the tests, and the RTD process work: CDL Drug and Alcohol Testing Rules and the Clearinghouse.

Two applicants, two clocks (illustration, not legal advice)

A 20-year-old applicant in Tennessee qualifies medically, proves residency, and earns a Class A CDL — valid for intrastate work only. On their 21st birthday the federal age bar lifts — one state errand remains, updating the self-certification (and dropping the intrastate-only restriction) with the licensing agency — and then the OTR applications go out. Meanwhile a 35-year-old with a five-year-old DUI from before ever holding a CDL is not federally barred from applying — 383.51's tables govern CLP and CDL holders — but state licensing rules and carrier hiring standards both see the record, and each gets its own vote. Individual situations differ; when a record is complicated, the state licensing agency is the authority on what it will issue.

Common mistakes

• Assuming 18 means OTR. It means intrastate — the 21 rule is federal.
• Booking the DOT physical with a non-Registry examiner. The certificate only counts from a National Registry examiner.
• Showing up with photocopies. Identity and residency proofs are original-document territory.
• Forgetting the self-certification category, then wondering why the state flagged the medical certificate.
• Treating personal-vehicle convictions as separate from the CDL. 383.51 counts them.

Eligibility checklist

• Age matches the driving you plan (21 interstate / state rules for 18–20 intrastate)
• DOT physical booked with a National Registry examiner
• Identity, lawful-status, and residency originals gathered per your state's list
• Any other state's license ready to surrender
• Driving record reviewed against 383.51 — know what a carrier will see
• Clearinghouse registration done (you'll need it for pre-employment queries)

Keep learning

• Next step in the journey: The CDL Permit Explained — and the full step-by-step guide
• The medical deep dive: The DOT Medical Card
• Start studying now, free: General Knowledge practice test
• Get exam-ready with structure: TLWS Academy · free fundamentals at CDL Pre-School · new guides by email.