Redefining walkability to capture safety: Investing in pedestrian, bike, and street level design features to make it safe to walk and bike

Walkable neighborhoods provide significant sustainability, health, and motorized user safety benefits. Far less consideration is given to the potential pedestrian/bicyclist safety-related implications of macro-level walkability. Making it desirable to walk and bike without providing the proper physical environment to make it safe is clearly problematic. This study assessed the links between neighborhood walkability and pedestrian/bicyclist traffic fatalities across metropolitan areas in the U.S. We integrated and harnessed geocoded data on pedestrian/bicyclist and all mode traffic fatalities, travel behavior exposures (use of sedentary and active travel modes), sociodemographic, and control variables. Associations of pedestrian/bicyclist traffic fatality rates with walkability characteristics were estimated using multilevel Tobit models with treatment for hierarchical unobserved regional and state variations. Walkability index (mixed land use, street intersection density, and transit accessibility) was positively correlated with pedestrian/bicyclist fatality rates after adjusting for travel exposures, sociodemographic controls, and regional and state-level unobserved variations. A unit increase in the walkability index was associated with a 4.9% increase (95% CI: 4.2%, 5.7%) in pedestrian/bicyclist fatality rates. Conversely, the walkability index was negatively correlated with total or all-mode fatality rates. The positive association between walkability and pedestrian/bicyclist fatality rates appeared robust in different sensitivity analyses. Despite non-linearities, neighborhoods with greater population using active travel modes for commute had on-average higher pedestrian/bicyclist fatality rates. The reverse was true for neighborhoods with greater teleworking population. Neighborhoods with greater prevalence of black, low-income, and younger adults had on-average higher pedestrian/bicyclist fatality rates. Results emphasize the need to develop new conceptual definitions of walkability that consider safety within the built environments. Our results highlight the importance of understanding how pedestrian/bicyclist supportive design can be used to maximize the positive health benefits of walkability while reducing the risk of pedestrian/bicyclist deaths. Findings also suggest the need to enhance existing walkability assessment techniques (indices) to predict and simulate how different investments impact pedestrian/bicyclist safety. Incorporation of objective pedestrian/bicyclist safety in walkability assessments can assist practitioners to simultaneously improve health while minimizing safety risks to vulnerable road users.