Is Smart Growth Associated with Reductions in Carbon Dioxide Emissions?

The transportation sector is the second largest contributor to human-generated carbon dioxide (CO2) emissions. A key goal of the U.S. Department of Transportation is to implement environmentally sustainable policies that can reduce carbon emissions from transportation sources. Smart growth—characterized by compact, mixed use; greater network connectivity; and environments friendly to alternative modes—may encourage reductions in vehicle travel and emissions. A better understanding of travel behavior in conventional and smart growth communities is needed to inform policies. A behavioral data set is analyzed to determine whether smart growth developments are associated with lower CO2 emissions. Sample selection models are estimated from a 2009 travel behavior survey of 15,213 households to capture the conditionality of emissions on the decision to drive (or not) by household members on a given day. Results indicated that 12% of responding households used alternative modes or did not travel from home; the rest of the sample traveled in an automobile and therefore contributed to CO2 emissions. CO2 emissions were calculated from vehicle miles traveled and the fuel efficiency of the vehicle used for specific trips taken by household members. The developed framework models whether CO2 emissions are associated with land use, sociodemographics, and preferences for adopting information technology. Tailpipe CO2 emissions are lower for households that reside in mixed land use neighborhoods with good network connections (on the order of 9%). As a long-term strategy, CO2 emissions reductions from smart growth developments can be substantial.