Economic determinants of urban form: resulting trade-offs between active and sedentary forms of travel.

Economic factors have an impact on how the built environment is shaped, which in turn affects how we choose to travel. Regional transportation investment decisions are firmly rooted in economic "cost-benefit" trade-off considerations. The placement (central or outlying) and mode of transportation in which investments are made (transit, highway, sidewalks, or bikeways) influence where homes, businesses, schools, and other types of uses are located. Transportation investments create or limit access and establish a set of economic trade-offs that help determine if an area will be compact or dispersed, and mixed use or single use. Developers consider cost trade-offs between constructing connected street grids versus disconnected cul-de-sac networks, which determines if residents can walk to services and transit. Taken collectively, transportation investments and resulting land-use patterns determine if destinations are far apart or close together and linked with direct and safe sidewalks or bikeways. The end result is a built environment that determines whether walking and biking is feasible or perceived as more beneficial than driving or taking transit. This paper assesses (1) the economic forces that shape transportation investment decisions, (2) the economic impact of these investments on land use, and (3) how we as consumers choose to travel as a result of these transportation investment and land-use decisions.