Va. Code § 58.1-604.1
In addition to the use tax levied pursuant to § 58.1-604 and notwithstanding the provisions of § 58.1-611, a use tax is levied upon the storage or use of all motor vehicles, machines, machinery, tools or other equipment brought, imported or caused to be brought into this Commonwealth for use in constructing, building or repairing any building, highway, street, sidewalk, bridge, culvert, sewer or water system, drainage or dredging system, railway system, reservoir or dam, hydraulic or power plant, transmission line, tower, dock, wharf, excavation, grading, or other improvement or structure, or any part thereof. The rate of tax is three and one-half percent through midnight on July 31, 2004, and four percent beginning on and after August 1, 2004, on all tangible personal property except motor vehicles, which shall be taxed at the rate of three percent; aircraft, which shall be taxed at the rate of two percent; and watercraft, which shall be taxed at the rate of two percent with a maximum tax of $1,000.
For purposes of this section, the words "motor vehicle" mean any vehicle which is self-propelled and designed primarily for use upon the highways, any vehicle which is propelled by electric power obtained from trolley wires but not operated upon rails, and any vehicle designed to run upon the highways which is pulled by a self-propelled vehicle, but shall not include any implement of husbandry, farm tractor, road construction or maintenance machinery or equipment, special mobile equipment or any vehicle designed primarily for use in work off the highway.
The tax shall be computed on the basis of such proportion of the original purchase price of such property as the duration of time of use in this Commonwealth bears to the total useful life thereof. For purposes of this section, the word "use" means use, storage, consumption and "stand-by" time occasioned by weather conditions, controversies or other causes. The tax shall be computed upon the basis of the relative time each item of equipment is in this Commonwealth rather than upon the basis of actual use. In the absence of satisfactory evidence as to the period of use intended in this Commonwealth, it will be presumed that such property will remain in this Commonwealth for the remainder of its useful life, which shall be determined in accordance with the experiences and practices of the building and construction trades.
A transaction taxed under § 58.1-604, 58.1-605, 58.1-1402, 58.1-1502, 58.1-1736 or 58.1-2402 shall not also be taxed under this section, nor shall the same transaction be taxed more than once under any section.
Va. Code § 58.1-604.1