How CDL tests differ by state
Federal rules set the CDL tests every state gives, so they are much alike, but each state writes its own questions from its own CDL manual. Here is how the 50 states compare.
- Tests in every state: General Knowledge, Combination Vehicles, Air Brakes, Doubles and Triples, Passenger, School Bus, Tank Vehicles and Hazardous Materials.
- Extra tests in some states: Charter Bus (Illinois) and Texas Commercial Rules (Texas).
- Number of tests: from 8 to 9. Which ones you take depends on your class (A, B or C) and the endorsements you need.
- General Knowledge: from 30 to 50 questions, and everyone takes it.
- Pass mark: 80% correct on every test except Illinois School Bus (90%).
Each state's CDL page shows which tests your class needs and has every test in its real format, with every answer explained and its manual page. The federal rules every CDL driver follows are on one page. Tests and rules change over time: always confirm the current tests with your state's licensing agency.