US vehicle fuel-efficiency choices: demographic,behavioral, and cultural factors

In the United States, a large proportion of greenhouse gas emissions are from personal vehicle use, and there are large differences in emissions between the most and least efficient vehicles. We use data from 2009 US National Household Travel Survey to characterize consumers who drive the most and least efficient vehicles. We calculate personal fleet efficiency based on all vehicles owned, reflecting the behavioral aspect of vehicle-use choices by owners. Though higher incomes provide the means to purchase more efficient vehicles, we find those with higher incomes more likely to drive low-efficiency vehicles. Higher education levels correlate with greater vehicle efficiency. While some efficiency differences are based on consumer characteristics such as family size, we find large differences that we attribute mostly to cultural preferences as observed by race, region, etc. From a policy perspective, these differences are of particular interest since they may be amenable to change.