"Exploring Land Use Impacts on Household Travel Choice and
                    Vehicle Emissions in the Atlanta Region"

                    Summary of paper by Larry Frank, Assistant Professor, Georgia Institute of
                    This study documents how land use impacts both household travel choices and
                    vehicle emissions. The paper finds that people in areas of the region with higher
                    employment density, residential density and street connectivity (the number of
                    street blocks per unit of area) drive and pollute less on a daily basis. This
                    relationship proved to be true even when controlling for income, household size,
                    and the number of vehicles owned per household. The most interconnected street
                    network is situated upon a grid pattern, while the most disconnected pattern of
                    street layout is based on the dead-end or cul-de-sac These findings indicate that
                    both proximity and connectivity are required to reduce vehicle miles/hours of
                    travel and vehicle trips.
                    This study provides evidence that land use policies are required for the long-term
                    reduction of traffic congestion and improved air quality. The inability to modify
                    current land development practices will likely undermine other ongoing efforts to
                    reduce traffic congestion and emissions. Findings from this study provide direction
                    for altering local land use actions to reduce vehicle dependence and emissions.
                    Policy Recommendations

                         Matching Growth and Regional Transportation   Regional efforts to
                         improve traffic and air quality conditions need to focus growth on existing
                         and emerging centers in a manner that achieves higher levels of density and
                         land use mix, and provides the infrastructure for a pedestrian environment.
                         Regional transportation investments targeted at increasing the desirability
                         and accessability of carpooling, transit, and non-motorized travel will have
                         limited effect on altering travel patterns and reducing mobile source
                         emissions without these supportive land use policies.

                         One Size Does Not Fit All   Land Use Strategies are required to address
                         the unique social and physical characteristics of central, suburban and ex-
                         urban areas of the region. Strategies are required to address the unique sets
                         of issues associated with retrofitting existing communities, such as
                         providing quality pedestrian and bicycle linkages between existing
                         residential, office, and commercial uses already located in proximity to one
                         another. In emerging communities, it is critical to provide alternatives to
                         auto travel. This can be achieved by locating residential, commercial and
                         recreational areas near developing transit corridors.
                         Comprehensive Approach   Land use policies required to reduce auto dependence need
                          to encourage both proximity and connectivity. Travel distances can be lessened through
                          the consolidation and intermixing of uses and the provision of increased pedestrian
                          connectivity and linkages between uses. Increasing the levels of density and land use mix
                          alone will not yield effective changes in travel patterns.

                          Demographic Factors   It is critical to recognize the underlying forces that manifest
                          themselves through community development patterns. Land use strategies to combat
                          congestion and air pollution will be ineffective if they are not accompanied by incentives to
                          spatially match housing types and labor markets and to address the effects of schools and
                          perceived levels of crime in residential locations.

                          Education and Empowerment   The general public needs to be made aware of the
                          hidden costs of current development practices and the potential benefits to the quality of
                          life that can be achieved through land use reform. Moreover, we need to get across the
                          fact that being stuck in traffic is linked with large lot, cul-de-sac subdivision planning
                          practices and that reduced traffic congestion, better air, and better physical health can be
                          achieved without giving up single family dwellings with private yards.

                    The study concludes that households located in areas that are more compact in nature and inter-
                    connected with commercial and/or employment districts are less auto dependent. The research
                    presented here indicates that moderate increases of two to five dwelling units per acre can be
                    linked to significant reductions in vehicle miles traveled and decrease the generation of harmful
                    emissions including NOx, carbon monoxide (CO), and volatile organic compounds (VOC).

                    Furthermore, moderate increases in street connectivity are also associated with reductions in
                    driving and air pollution per household. However, increasing residential or employment densities
                    or the level of street connectivity alone will likely yield little change in travel choice. Instead, land
                    use changes need to be made within the context of accessible transit service for regional travel and
                    high quality pedestrian environment to encourage walking. Land use reform, regional transit
                    investment, and an improved walking environment need to go hand in hand. Given these
                    qualifiers, the results of this study indicate that the improvement of Atlanta's air quality can be
                    partially achieved through the alteration of current land use practices.

For more information, contact Larry Frank, 404/894-6488.