Truck and trailer rules in Tennessee: licence classes, size and weight limits
What the Tennessee Department of Safety and the Department of Transportation say about commercial licence classes at 26,001 pounds, the age 21 limit, the 80,000 pound gross weight, 8 feet 6 inch width, 13 feet 6 inch height and the 75 foot length for logs and timber.
Checked against the sources at the bottom of this page on October 9, 2026. Rules, fees and pay change: the source has the last word.
This page reports what the official source says. It is not legal advice: ask the office named here. The sources are the Tennessee Department of Safety pages and commercial driver licence manual, and the Tennessee Department of Transportation (TDOT) rule chapter 1680-07-01 with its oversize and overweight permit office page. The TDOT chapter names the size and weight sections of the Tennessee Code, T.C.A. sections 55-7-201 to 55-7-203, and restates their limits. Federal background and the other places are on the parent page, trucks and trailers for tree work.
At a glance
| Item | What the sources say |
|---|---|
| Class A | Combination rated 26,001 pounds or more with a towed unit rated 10,001 pounds or more |
| Class B | Single vehicle rated 26,001 pounds or more, towing up to 10,000 pounds |
| Age | 18 or older; under 21 limited to driving within Tennessee |
| Trailer brakes | Not published on the pages read |
| Safety chains | Not published on the pages read |
| Width, height | 8 feet 6 inches wide; 13 feet 6 inches high |
| Length | 45 feet straight truck; 65 feet truck with trailer; 75 feet total for poles, logs or timber in single length pieces on a truck tractor with a semi-trailer or trailer |
| Weight | 80,000 pounds gross; 20,000 pounds single axle; 34,000 pounds tandem axle |
| Carrier number | Not published on the pages read |
Licences
The Department of Safety says commercial licences come in Class A, B and C by the gross vehicle weight rating, the gross combination weight rating and what is carried. A commercial motor vehicle is in general a vehicle or combination rated over 26,001 pounds, one carrying hazardous materials, or one designed for more than 15 passengers including the driver. For Class A the page says the combination must be rated 26,001 pounds or more and the trailer 10,001 pounds or more; with a trailer of 10,000 pounds or less the licence is Class B. Class B is a single vehicle rated 26,001 pounds or more, or one towing a vehicle or trailer rated up to 10,000 pounds. Class C is a vehicle built for more than 15 passengers or one carrying hazardous materials. A commercial licence is also valid for a Class D vehicle.
Applicants must be at least 18 years old. Those under 21 are limited to operating within Tennessee. All applicants must pass vision, knowledge and skills tests, and new applicants must complete Entry Level Driver Training from a registered provider. The state commercial manual adds that a driver of a double or triple trailer needs the T endorsement and a special knowledge exam. See the Department of Safety page on the commercial driver license.
Size and weight
Rule 1680-07-01-.01 of the TDOT chapter says a special permit is required for a motor vehicle on the state highway system, interstate included, when the vehicle and load exceed the limits set by law. It restates them in a table citing T.C.A. sections 55-7-201 to 55-7-203. Gross weight is 80,000 pounds, though a freight vehicle on the interstate may not exceed the lesser of 80,000 pounds or the figure from the formula in section 55-7-203(b)(3). A single axle is 20,000 pounds and a tandem axle 34,000 pounds. Width is 8 feet 6 inches and height 13 feet 6 inches.
The table gives length limits of 45 feet for a straight truck and 65 feet for a straight truck with a trailer attached. For a truck tractor with a semi-trailer or trailer, the towed vehicle may not exceed 50 feet from the point of attachment to the tractor. If it exceeds 48 feet, the distance from the kingpin to the rearmost axle, or to the midpoint of a tandem, may not exceed 41 feet. The truck tractor row also allows 75 feet total length when transporting poles, logs or timber in single length pieces. A truck tractor with twin trailers is limited to 28 feet 6 inches for either towed vehicle. The chapter says a single trip permit is valid for ten calendar days with no extension, and that annual permits are provided for in section 55-7-205.
The TDOT oversize and overweight permit office page says the office issues permits for loads that exceed statutory size or weight limits and gives a phone number of (615) 741-3821. The pages read do not state the brake or safety chain requirements of Title 55 chapter 9.
Sources
- Tennessee Department of Safety, Commercial Driver License, read October 9, 2026
- Tennessee Department of Safety, Commercial Driver's License Manual (May 2022), read October 9, 2026
- Tennessee Department of Transportation, Rules chapter 1680-07-01 overweight and overdimensional movements on Tennessee highways, read October 9, 2026
- Tennessee Department of Transportation, Oversize and Overweight Permits, read October 9, 2026