Although county officials have certain powers with regard to weight limits on county roads, this authority is derived from authority possessed by the State Department of Transportation. The ability to regulate weight limits on county roads must fit within the overall scheme of state laws and regulations. For that reason, the following is a summary of the power and authority exercised by the Department of Transportation.

T.C.A. § 55-7-101 - Operation of Vehicles Injurious to Highways Must Conform to Regulations -- No vehicle, truck, engine, or tractor of any kind, whether such vehicle be propelled by steam, gasoline, or otherwise, shall be permitted to operate upon any street, road, highway, or other public thoroughfare which, either by reason of its weight or the character of its wheels, will materially injure the surface or foundation of such street, road, highway, public thoroughfare, including the bridges thereon, unless and until the owner or operator of such vehicle of any kind shall have complied with such rules and regulations as may be prescribed by the departments of transportation and safety relating to the use of such highways by such vehicles. 

Statutes regulating the size, weight, and load of motor vehicles traveling on Tennessee highways are codified as Title 55, Sections 55-7-101 -- 55-7-209.

Section 55-7-103 describes when maximum weight limits may be lowered:

Maximum Weight May be Lowered, When - Notices to be Posted -- (a) From January 15 to April 15 of each year, and at any other time by reason of repairs, weather conditions, or recent construction of the road, the maximum weight herein permitted would damage the road, the [state] department of transportation may specify any lower maximum weight which, in the discretion of such department, is necessary in order to protect such streets, roads, highways, or other public thoroughfares from unnecessary injury or damage.

(b) Notice of such reduction in weight load shall be given by the department by posters posted at the termini of the road and all detours for one (1) week before such reduction of load becomes effective.

Violation of regulations contained in Sections 55-7-101--55-7-103 is a Class C misdemeanor and, upon conviction, subject to imprisonment for not greater than thirty (30) days or to a fine of not more than fifty dollars ($50.00). (Sections 55-7-104, 40-35-110, 40-35-111) In addition, it is illegal to move an overloaded vehicle until the load has been reduced to bring it into legal compliance, or a special permit obtained. Failure to comply is a Class C misdemeanor.

Sections 55-7-107--55-7-109 relate to securing of loads of vehicles hauling timber, pulpwood, logs (T.C.A. § 55-7-107) and loose material hauled in an open truck bed (T.C.A. § 55-7-109), and penalties for violation of these sections. Sections 55-7-201 and 55-7-202 outline maximum length, width and height regulations.

MAXIMUM WEIGHT LIMITS

Section 55-7-203 sets out weight limits currently established for public highways in Tennessee, as follows:

Gross Maximum Weight Limit 80,000 lbs.

Single Axles 20,000

Tandem Axles 34,000

The maximum weight limits for vehicles equipped with emissions-reduction technology may be increased by the weight of that technology up to 550 lbs. or the maximum amount allowed by federal law. 

Section 55-7-203(c) sets out special provisions for nondivisible overweight loads. 

Weight limits for the interstate system are slightly different than those outlined above for state highways. (For a complete explanation of weight limits, please refer to Section 55-7-203).

In addition, Section 55-7-203(b)(7), relates to allowances for error on logging trucks, farm trucks, and certain other vehicles:

(b)(7) For purposes of enforcement of this section, weight restrictions shall be deemed to have a margin of error of ten percent (10%) of the true gross or axle weight for all logging, sand, coal, clay, shale, phosphate, solid waste, recovered materials, farm trucks and machinery trucks when being operated over the state highway system other than the portion designated as the interstate system.

The various types of trucks listed in that statute are defined specifically in the law. The application of the margin of error rule to trucks hauling certain types of materials (machinery, sand) is limited to specific circumstances or distances.

OVERWEIGHT, OVERSIZE, OVERLENGTH LOADS

The law not only sets the maximum axle and gross weight limits allowed on Tennessee highways, but also authorizes that "....the commissioner of transportation shall have the authority to grant special permits for the movements of freight motor vehicles carrying gross weights in excess of the gross weights set forth in Section 55-7-203, or dimensions in excess of the dimensions set forth in Sections 55-7-201 and 55-7-202, and shall charge a fee in accordance with the schedules contained in subsection (h) for the issuance of a permit for each movement." (T.C.A. § 55-7-205(a)) These special permit fees are charged in accordance with the following schedules set out in Section 55-7-205 (h):

Excessive Width:

Not More Than 14 Feet $ 20.00

Over 14 Feet - Not More Than 16 $ 30.00

Over 16 Feet -- $ 30.00 plus $ 5.00 for each additional foot or fraction thereof greater than 16 feet.

Houseboats over 17 feet – two thousand five hundred dollars ($2,500), plus one hundred dollars ($100) for each additional inch or fraction thereof greater than seventeen feet (17').

Excessive Height or Length: $ 20.00

Excessive Weight: $ 20.00 plus $.06/Ton per Mile

Evaluation of Bridges and Similar Structures:

> Movements weighing over 165,000 but not more than 250,000 pounds: $ 100.00

> Movements weighing over 250,000 but not more than 500,000 pounds: $ 300.00

> Movements weighing over 500,000 pounds: Actual Cost

A permit shall be available from the department of transportation on an annual basis for overdimensional and/or overweight vehicles except for those vehicles specifically permitted and used to transport cotton seed modules, overdimensional boats used for noncommerical purposes and mobile homes. 

EXCEPTIONS TO SIZE AND WEIGHT PROVISIONS

Section 55-7-205 (a) allows certain exceptions pertaining to size and/or weight limits as follow:

Farm Equipment:

....It is not necessary to obtain a permit nor is it unlawful to move any vehicle or machinery in excess of the maximum weight and height....used for normal farm purposes only where the same is hauled on a farm truck....or such vehicle or machinery is being transported by a farm machinery equipment dealer or repairman in making a delivery thereof of new or used equipment or machinery to the farm of the purchaser thereof, or in making a pickup and delivery of such farm machinery or equipment from the farm to a shop of a farm equipment dealer or repairman for repairs and return to the farm, and such movement is performed during daylight hours within a radius of fifty (50) miles of the point of origin thereof and no part of such movement is upon any highway designated and known as a part of the national system of interstate and defense highways of any fully controlled access highway facility.

Utility Companies:

No fee authorized by this section shall be charged for the issuance or renewal of such special permits to retail electric service owned by a municipality or electric cooperative corporation, or to any telephone company or to contractors when they are moving utility poles doing work for such utilities. Upon compliance with the appropriate rules and regulations, such electric services, telephone companies, and their contractors when they are moving utility poles may be issued special permits for stated periods not exceeding one (1) year.

PENALTIES FOR VIOLATIONS

Under T.C.A. § 55-7-206, each violation of Sections 55-7-201--55-7-203, each violation of restrictions on the maximum gross weight of freight motor vehicles adopted by the commissioner of transportation (Section 55-7-205), and each violation of rules and regulations adopted by the commissioner of safety under that section, is a Class C misdemeanor. In addition, when any freight motor vehicle is found to be in violation of only T.C.A. § 55-7-203(b)(3), a fine of twenty-five ($25.00) is to be imposed. (Section 55-7-206 (d)(1)).