The Code of Virginia specifies that, for most vehicles, the value be (1) from a recognized pricing guide, (2) applied uniformly, and (3) as of January 1 of the tax year. To meet these requirements, Fairfax County uses the January edition of the J.D. Power Associates Valuation Services Used Car Guide. (Code of Virginia, Section 58.1-3503(A)(3) & Section 58.1-3515)
Localities are authorized to use the pricing guide values that include all applicable adjustments or use the base value for vehicles specified in the guide. Localities can use either average retail, wholesale, trade-in, or loan value, so long as these values are applied uniformly within classifications of property. For most vehicles, Fairfax County has chosen to use the clean trade-in value as listed in the pricing guide. However, for new model year vehicles, the assessed value is based on a percentage of MSRP, and pricing guide values are used for subsequent years. Discounting from the MSRP provides a uniform assessment for each class of new model vehicles and generally provides a reasonable, but conservative depreciation curve when compared to the values in next year's pricing guide.