Since information on US household expenditures has been collected, transport expenditures have risen from the sixth highest share of household budgets, less than two percent in 1917, to the second highest share since the 1970s. This rise is linked to increased auto purchase and maintenance and a relative decline in costs for other items, namely food. Studies also link travel expenditures to differences in the built environment. However, since the annual Consumer Expenditure Survey is reported at the metropolitan level, it cannot be used to test this latter influence. Regional travel demand models recognize the dual influence of land use and household characteristics, but do not include sufficient detail on the built environment of each neighborhood. Additionally, these models report travel time, distance, and frequency, but not out-of-pocket household transportation expenditures. Therefore, this study was launched to create a statistical model to predict household total annual transportation expenditures for each neighborhood in the largest regions in the US given the built environment and household size and income. The model uses seven independent variables to measure density, jobs access, neighborhood services, walkability, and transit connectivity. Model parameters were calibrated to actual auto ownership and transit use in the pilot region, Minneapolis-St. Paul, and to vehicle miles traveled by block group in the National Household Travel Survey. Statistically significant results confirm the influence of the built environment and regional accessibility on transport expenditures. Intended users are households, policy makers, and planners making location, design and investment decisions.
Abstract