The CDL test has two parts, knowledge and skills, and the rules for both are federal. States write the questions and run the test centres, but the content, the order, the pass marks and the ways to fail automatically are set in 49 CFR Part 383 subparts G and H. This page lays out what an examiner is required to check, so that practice time goes to the right things.
The knowledge tests
383.133(b)(1): states build knowledge tests from an FMCSA-approved question pool. (b)(2)(ii): a quarter of the questions in each new version must be new, and (b)(4): a retake must use a different version than the one failed. Memorising one set of answers is not a plan.
383.135(a)(1): the pass mark on each knowledge test is 80 percent. Two consequences are written into the same paragraph: failing the air brake section still allows a permit or license, but with the L restriction (a)(2); failing the combination vehicle section means no Class A (a)(3). 383.133(b)(3) allows the test in a foreign language provided no interpreter is used.
The skills test: three segments, in order
383.133(c)(6): the segments are taken in a fixed order, pre-trip inspection, basic vehicle control, on-road. Failing one ends the test; the next segment is not attempted. Passed segments count only during the initial issuance of the learner's permit, so renewing the permit means taking all three again.
383.133(c)(5): no interpreters on the skills test. The applicant must understand and respond to the examiner's verbal instructions in English, and neither side may use another language during the test.
Segment 1: pre-trip inspection
383.113(a)(1): the applicant must identify each safety-related part and explain what is inspected to ensure it is safe, covering the engine compartment, cab and engine start, steering, suspension, brakes, wheels, side of vehicle, rear of vehicle, and special features of a tractor-trailer, school bus or coach if one is used.
383.113(a)(2) adds six air brake checks for air-braked vehicles:
- locate and name the air brake controls and gauges;
- check brake adjustment and that the air connections between vehicles are made and secured;
- check that the low pressure warning activates;
- with the engine running, check that the system maintains adequate air;
- check that air build-up time is within limits and that alarms and emergency devices deactivate at the right pressure;
- operationally check the brakes.
The pre-trip is spoken. What is scored is naming the part and saying what is being checked for, which is why schools drill a fixed script.
Segment 2: basic vehicle control
383.113(b) lists seven skills: start, warm up and shut down; move off and accelerate smoothly forward and back; stop smoothly; back in a straight line while checking path and clearance; position for and make left and right turns; shift and select gears; and back along a curved path. States turn these into range exercises such as straight line backing, offset backing and parallel or alley-dock parking, scored under the examiner manual.
Segment 3: on-road driving
383.113(c) lists eight: visual search; signalling; adjusting speed to road, weather, traffic and load; choosing a safe gap for lane changes, passing and entering traffic; positioning before and during turns to prevent passing on the wrong side and to handle off-tracking; keeping a safe following distance; adjusting to weather; and watching other vehicles before changing speed or direction. 383.113(d): the test runs on-street, or on-street and off-street combined. (e): simulators may be used but never instead of the on-street test.
Automatic failure
383.135(b)(2): an applicant who does not obey traffic laws, causes an accident, or commits any other automatic-failure offense in the state manuals fails the test outright. In practice the common ones are rolling a stop, a curb strike on a turn, and failing to stop at a railroad crossing where required.
The test vehicle decides your restrictions
383.133(c)(3): the test vehicle must be representative of the class sought, judged by its GVWR or GCWR. And under 383.135(b)(3) to (6), a test in a vehicle without air brakes, with air-over-hydraulic brakes, with an automatic transmission, or with a non-fifth-wheel coupling puts the L, Z, E or O restriction on the license. (b)(8): removing O means retaking all three segments in a tractor-trailer. The classes and endorsements page has the full code table.
Before test day
- The learner's permit must be at least 14 days old (383.25(e)).
- If you are new to Class A or B, the school must have reported your entry-level training to the Training Provider Registry before the state will test you; the ELDT page covers the reporting deadline.
- Know which vehicle you will test in, and whether it has air brakes and a manual transmission.
State-run and third-party CDL testing locations are listed by state and town.