Q. Registered Vehicle and Licensed Driver Statistics
You can find the population, number of drivers, and number of vehicles for 2010 in section 6 and 7 of the publication Highway Statistics 2013 available from the Federal Highway Administration.
This includes a variety of vehicle types (car, truck, trailer, motorcycle) and driver age and sex categories. This does not include the number of new drivers for each year.
You can access earlier Highway Statistics publications (for 1992-2009) here.
Historical driver licensing data for the period ending 1995 can be found in the Highway Statistics Summary To 1995.
Historical motor vehicle registration statistics for the period ending 1995 are available here.
To see multiple years of vehicle statistics in one table, see table 1-11: Number of U.S. Aircraft, Vehicles, Vessels, and Other Conveyances, in National Transportation Statistics.
Please note that we do not know of any US DOT source of vehicle/driver statistics on the local level (city, county, etc.). Your best option is probably to contact the relevant state departments of motor vehicles, or other licensing agency.