Most US drivers operate under a standard Class D license. A small but growing number need a Commercial Driver License (CDL) for work. Here's how to know which one you need.
Class D — the standard license
A Class D license (sometimes called Class C in California, Texas, and a handful of other states) covers any passenger car, pickup truck, SUV, or van under 26,001 pounds gross vehicle weight, including any trailer the vehicle is rated to tow. That covers virtually every consumer vehicle on the road, plus most rental moving trucks under the 26,001-pound threshold.
When you need a CDL
You need a Commercial Driver License if you operate any single vehicle 26,001 pounds or more, any combination over 26,001 pounds with a trailer over 10,000 pounds, any vehicle designed to carry 16 or more passengers including the driver, or any vehicle of any weight transporting hazardous materials in placardable amounts. [Recommended driving resource]
CDL classes
Class A covers combination vehicles over 26,001 pounds with a towed unit over 10,000 pounds — semi-trucks and large trailers. Class B covers single vehicles over 26,001 pounds, including straight box trucks and most passenger buses. Class C covers vehicles under 26,001 pounds that carry 16+ passengers or hazardous materials.
CDL endorsements
A CDL by itself doesn't authorize you to drive everything in your class. You also need endorsements: P for passenger vehicles, S for school buses, T for double or triple trailers, N for tank vehicles, H for hazardous materials, and X for combined tank and hazmat. Each endorsement requires its own knowledge test, and the H endorsement requires a TSA background check.
CDL medical certification
CDL holders must obtain a medical examiner's certificate ("med card") every two years, or more often if a medical condition requires it. The exam covers vision, hearing, blood pressure, and a urine test for diabetes. Drivers with sleep apnea, insulin-treated diabetes, or certain heart conditions may need additional documentation.
CDL BAC limit
The BAC limit for any driver operating a commercial vehicle is 0.04%, regardless of whether the underlying license is Class D or CDL. A commercial driver convicted of DUI loses their CDL for at least one year on the first offense and for life on the second. Many CDL holders also lose their Class D driving privileges as part of the same penalty.
CDL versus regular permit prep
PermitPrep covers the standard Class D permit test for all 50 states. If you need CDL prep, your state's commercial driver handbook is the right starting point — most are available free as PDFs from the DMV website.