Tennessee Code Title 55. Motor and Other Vehicles § 55-1-109

“Special mobile equipment” means every vehicle not designed or used primarily for the transportation of persons or property and only incidentally operated or moved over a highway or street, including, but not limited to: ditch-digging apparatus and road construction and maintenance machinery, such as asphalt spreaders, bituminous mixers, bucket loaders, tractors other than truck-tractors, ditchers, leveling graders, finishing machines, motor graders, road rollers, scarifiers, scrapers, track mounted power shovels and drag lines. “Special mobile equipment” does not include dump trucks or truck mounted transit mixers, earth movers, cranes, shovels, well-boring apparatus and feed mills, such as may be fixed load vehicles or other vehicles designed for the transportation of persons or property to which machinery has been attached, even though the movement over the streets and highways may be only incidental to the operation of such vehicle.