Another Look at Vehicle Miles Traveled

Abstract

This study analyzed the determinants of vehicle miles traveled (VMT) with data from the 2009 National Household Travel Survey. First, total VMT models were estimated across all households. Next, the survey sample was segmented by the number of vehicles owned, and separate models were estimated for each sample segment. Finally, with a focus on two-vehicle households, a seemingly unrelated regression model was formulated to analyze total household VMT and the VMT share of each vehicle. Household increases in income and number of vehicles, workers, adults, and children all led to higher VMT. Population density and gasoline cost negatively affected VMT. Other findings of the total VMT models were related to telecommuting and vehicle characteristics. Results indicate that having the option to telecommute and owning SUVs, pickup trucks, vans, or hybrid vehicles increase VMT. If the driver of a vehicle was a female, older, unemployed, or did not hold a bachelor's degree, that vehicle's share of the total household VMT decreased. If this vehicle was an SUV, a pickup truck, a van, or a hybrid, it was likely to be used more. These significant effects have important implications for understanding the substitution patterns in multivehicle households.