Carbonless footprints: promoting health and climate stabilization through active transportation.

OBJECTIVE: Our objective was to describe how active transportation can help meet health and greenhouse gas emissions goals, and the ability of urban form strategies to impact both issues. In addition, we wanted to assess if there is an inverse relationship between active and motorized forms of travel.
METHODS: A cross-sectional analysis of travel diary data was used to measure relationships among energy (kcal) burned from walking, energy (kcal) burned from motorized transportation, and the ratio of the two (the transport energy index) with regional accessibility and local walkability when adjusting for demographic factors. Multiple linear regression and descriptive statistics were employed to estimate these relationships.
RESULTS: Transit accessibility, residential density, and intersection density were positive predictors of walk energy and the energy index and inverse predictors of motorized energy. The land use mix variable was negatively and significantly associated with energy burned from walking and from motorized transportation, with no significant impact on the transport energy index. Because a mixed land use pattern places destinations closer together, it reduces distances and thus energy demands for both walking and driving.
CONCLUSIONS: The results support the concept, previously untested empirically, that similar urban form strategies can have cobenefits for both physical activity and climate change.