Commercial Motor Vehicle Knowledge, Skills, and Physical Ability Requirements
Knowledge and inspection
The general-knowledge test covers vehicle systems, cargo securement, braking, railroad crossings, and safe operating practices. The skills test has three parts: pre-trip inspection, basic vehicle control, and a road test. In pre-trip you must show that the vehicle is safe to drive-checking coupling devices, air lines, landing gear, tires, lights, brakes, and cargo securement-not merely naming parts. Basic control includes turns, lane changes, stops, and backing. The road test scores traffic checks, speed, lane position, and use of mirrors.
Physical ability
A CDL driver must meet federal physical qualification standards and carry a valid medical examiner's certificate unless an exception applies. Vision must be at least 20/40 in each eye with or without correction, with a field of vision of at least 70 degrees and the ability to recognize red, green, and amber. Hearing must allow perception of a forced whisper at 5 feet, with or without a hearing aid. Drivers self-certify their operating category; a non-excepted interstate driver must keep the medical certificate current. Corrective lenses or hearing aids may carry a restriction on the CDL.
Worked example
An applicant sees 20/50 uncorrected but 20/25 with glasses and has a 70-degree visual field. The vision standard is met with corrective lenses, so the CDL can be issued with a corrective-lens restriction. If the corrected acuity were 20/50, the applicant would not meet the standard and could not be certified merely by promising to wear glasses.
Traps
Do not think the pre-trip is a memory recital; you must identify defects and explain why they matter. Do not assume a medical certificate lasts forever-it expires and must be renewed. A skill-test automatic failure can come from an unsafe act, not just a poor score. Hearing aids and glasses are allowed if they bring you to standard, but restrictions will appear on the license.