Estimating Transportation Costs by Characteristics of Neighborhood and Household

Abstract

Since information on U.S. household expenditures was first collected, transport expenditures have risen from the sixth-highest share of household budgets, less than 2%, in 1917 to the second-highest share since the 1970s. This rise is linked to increased automobile purchase and automobile use and a relative decline in other costs, particularly food. Studies have also linked variations in the built environment to transport expenditures, but this influence cannot be tested by the federal Consumer Expenditure Survey since it is reported at the metropolitan level. 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 neighborhoods. Additionally, these models report travel time, distance, and frequency but not out-of-pocket household transportation expenditures. A study was launched to create a statistical model to predict household total annual transportation expenditures for each neighborhood in the largest metropolitan regions in the United States, controlling for the built environment and household size and income. The model specifies five independent variables—density, jobs access, neighborhood services, walkability, and transit connectivity. Model parameters were calibrated to measured vehicle ownership and transit use in the pilot region, Minneapolis–St. Paul, Minnesota, and to vehicle miles traveled by households at the block group level 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.