A new congressionally mandated report from the National Research Council, DRIVING AND THE BUILT ENVIRONMENT: THE EFFECTS OF COMPACT DEVELOPMENT ON MOTORIZED TRAVEL, ENERGY USE, AND CO2 EMISSIONS, examines how suburbanization -- made possible largely due to the prevalence of automobiles and the extensive U.S. highway system -- impacts the number of miles we drive, our reliance on petroleum fuel, and the percent of greenhouse gas emissions from transportation. The report looks at studies on compact, mixed-use development where people live in denser environments with jobs and shopping close by, to determine whether a shift to this type of land use could lessen vehicle use, energy consumption, and CO2 emissions.