The Tennessee Highway Patrol (THP) has begun enforcement of weight limits on dump trucks and ready mix trucks on the Interstates. They are using portable scales to weigh vehicles.
Please remember that the weights you can haul in dump trucks and ready mix trucks on non-Interstate routes are very different from hauling on the Interstate System.
See attached TDOT Circular Letter 109.01-02 concerning truck weight limits on non-interstate highways and Interstate highways, where you must comply with the federal Bridge Formula. The Federal Bridge Formula does not permit the heavier weights on the Interstate System that you can haul on non-interstate highways. Please consult the following link to determine how much you can haul in your trucks on the Interstates.
On non-interstate routes, according to TCA 55-4-124 (below), you can haul up to 74,000 lbs. with a four axle truck and up to 66,000 lbs. with a 3 axle truck.
55-4-124. Registration of vehicles hauling certain materials.
(a) Any vehicle, freight motor vehicle, truck-tractor, trailer or semitrailer or combinations of these vehicles that transports crushed stone, fill dirt and rock, soil, bulk sand, coal, clay, shale, phosphate muck, asphalt, concrete, other building materials, forest products, unfinished lumber, ferrous and non-ferrous scrap metal, agricultural lime, liquid fertilizer, solid waste, coal ash and agricultural products shall be permitted to register as follows:
(1) The vehicles hauling such products in a single unit motor vehicle having four (4) axles and designed to unload itself, with a gross weight not exceeding seventy-four thousand pounds (74,000 lbs.) including the load thereon, shall be permitted to register as a Class 10 vehicle, or purchase the appropriate special zone tag; and
(2) The vehicles hauling such products in a single unit motor vehicle having three (3) axles and designed to unload itself, with a gross weight not exceeding sixty-six thousand pounds (66,000 lbs.) including the load thereon, shall be permitted to register as a Class 9 vehicle, or purchase the appropriate special zone tag.
(b) If the commissioner of transportation is formally notified by an appropriate federal official that, as a result of any provision of this section, the state will lose federal funds, then the provision shall be void and inoperative.
(c) Nothing contained in this section shall be construed as authorizing these vehicles to use that portion of the state highway system designated as the interstate system.