I’m a huge fan of public transportation – I take the bus to and from work every weekday. But I also love the convenience of owning a car. Not surprisingly, so does most of the USA.

In this post, I’ve mapped vehicle ownership by county in three ways. The largest map is simply the average number of vehicles per household. I was also curious about the extremes, though, so in the smaller maps, I calculated the percentage of households that has excess vehicles (i.e., more vehicles than people) (bottom left), and the percentage that has no vehicles at all (bottom right). Note that the calculation for excess vehicles was based only on one-, two-, and three-person households due to how the Census binned the data.

Overall, there is no statistically significant relationship between a county’s population and the number of vehicles per household. Looking at the map, there appears to be a slight preference for more vehicles per household around the Northern Rockies and Great Plains, as well as around northern Virginia. The nine counties with the highest averages (>2.7) are in North Dakota, South Dakota, Montana, and Nebraska. The nine counties with the lowest averages (<0.8) are in New York and Alaska. The national average is 1.77 vehicles per household.

The vast majority of households (approximately 77%) own a vehicle, but not more than the number of people in the household. The less common situations are to have excess vehicles (13.9% of US households), or not to own any vehicle (8.9% of US households). So a household is slightly more likely to have excess cars than it is to have no cars. On both of these maps, I highlighted the extreme counties in yellow for easy identification of the outliers. These include counties where more than 50% of households have excess vehicles, and where more than 20% of households have no vehicle.

Thanks to Andrew Levitt for suggesting the topic!

Data source: http://factfinder2.census.gov/ (Tables B25046 and B08201)