Household Motor Vehicle Ownership and Use: How Much Does Residential Density Matter?

The question of whether population density affects the amount of household automobile travel in the United States is revisited. Controls for income and demographics are included in a multivariate regression model of vehicle travel that includes vehicle ownership as an intermediate factor and that treats a household's pick of neighborhood density and the amount of travel as a simultaneous relationship. The data come from the 1990 Nationwide Personal Transportation Survey. It is found that density matters, but not much. A 10 percent increase in density leads to only a 0.7 percent reduction in household automobile travel. By comparison, a 10 percent increase in household income leads to a 3 percent increase in automobile travel. The results are similar when vehicle trips are used as the dependent variable. The effect of density is so small that even a relatively large-scale shift to urban densities would have a negligible impact on total vehicle travel.