What Disqualifies You From Getting a CDL? (DUI, Drug Tests, Medical & More)

Before you spend a dollar on CDL school, you deserve a straight answer to the uncomfortable question: is there anything in my past — or my health — that blocks me? Here's the honest list, from the federal rules (49 CFR 383.51) and FMCSA programs.

DUI — the big one

• A DUI in any vehicle — including your personal car — disqualifies you from commercial driving for 1 year on a first offense.
• A second DUI means lifetime disqualification (some states allow reinstatement after 10 years with completed rehab).
• Refusing a lawful alcohol test counts the same as failing one.

Drug and alcohol testing — the Clearinghouse

Every CDL driver is tracked in the FMCSA Drug & Alcohol Clearinghouse. Fail or refuse a DOT drug test and you're flagged 'prohibited' — and since November 2024, your state must downgrade your CDL itself until you complete the return-to-duty process. Every employer checks the Clearinghouse before hiring, so there's no driving around it.

Felonies

Using a commercial vehicle to commit a felony brings disqualification — and using one for drug trafficking is a lifetime ban with no reinstatement. Ordinary felonies unrelated to driving usually do NOT block a CDL itself, though some employers and endorsements (like Hazmat's TSA background check) apply their own screens.

Medical

You need to pass a DOT physical with a National Registry medical examiner. Conditions like insulin-treated diabetes, certain heart conditions, epilepsy, and poor vision are evaluated case-by-case — many drivers qualify with treatment, documentation, or federal exemption programs. Don't self-disqualify: get the exam and find out.

What does NOT disqualify you

• Speeding tickets or a less-than-perfect record — points matter to insurers and employers, but they don't bar you from earning the license.
• Being 18–20 years old — you can hold a Florida CDL; you're just limited to in-state driving until 21.
• English as a second language — you must be able to operate in English (and Florida tests in English only since Feb 2026), but bilingual training gets thousands of drivers there every year.
• A years-old dismissed charge or misdemeanor — most have no CDL effect; when in doubt, ask before assuming.