Source: http://www.fairfaxcounty.gov/dta/tax_rates.htm

Car Tax - $4.57 per $100 of assessed value except for properties included in the special subclass for personal property taxation. For properties in this
special subclass, the tax rate is $0.01 per $100 of assessed value. Property types included in this special subclass are as follows:
privately-owned vans used for van pools
vehicles belonging to volunteer fire and rescue squad members
vehicles specifically equipped for the handicapped
automobiles and pick-up trucks owned by certain qualifying elderly and disabled individuals
vehicles owned by qualified disabled veterans
vehicles owned by auxiliary police officers
vehicles owned by auxiliary deputy sheriffs
aircraft and flight simulators
antique motor vehicles
boats
certain property owned by homeowners' associations

In other words you are going to pay a LOT more tax for your car, unless it is an antique, than you will for your Hinckley yacht