"Among the report's findings: More compact development patterns are likely to reduce VMT. The most reliable studies estimate that doubling residential density across a metropolitan area might lower household VMT by 5 to 12 percent, and perhaps by as much as 25 percent, if coupled with higher employment concentrations, significant public transit improvements, mixed uses, and other supportive demand management measures. More compact, mixed-use development can produce reductions in energy consumption and CO2 emissions both directly and indirectly. Significant increases in more compact, mixed-use development result in only modest short-term reductions in energy consumption and CO2 emissions, but these reductions will grow over time."
The full report is available for download from Reconnecting America.