vary by the specific types of compact development policies and the contexts in which they are applied.
Given the uncertainties, it would be wise to proceed carefully, monitoring the results and taking into account new research as it adds to the understanding of the benefits and costs that various compact, mixed-use development policies generate at different places and times. But given that the full energy and emissions benefits of land use changes take decades to realize, and current development patterns take years to reverse, it is important to start implementing these policies soon.
The committee was often stymied in its effort to identify causal linkages between land development patterns and VMT and to quantify the magnitude of effects on energy use and CO2 emissions. If land use measures are to become part of the nation’s strategy to achieve greater energy efficiency and reduce CO2 emissions, more precise estimates of the effects of such policies will be required.
Recommendation 2: More carefully designed studies of the effects of land use patterns and the form and location of more compact, mixed-use development on VMT, energy use, and CO2emissions should be conducted so that compact development can be implemented more effectively.
In particular, the committee identified five areas in which more research would be productive:
Longitudinal studies: Federally funded empirical studies based on panel data would allow better control for socioeconomic characteristics and self-selection, thus helping to isolate the effects of different