Spatial Analysis of Relationships Between Intersection Safety, the Urban Built Environment, and Average Income Level: A Case Study of Des Moines

This study makes a methodological contribution by exploring the relationship between motor vehicle traffic crashes at intersections and the built environment. The study focuses on specific neighborhoods within the city of Des Moines, Iowa, with contrasting socio-economic characteristics to examine variation between the neighborhoods. Exploratory spatial data analysis was used to locate crash clusters at intersections using seven-year crash data (2013-2019) obtained from the Iowa Department of Transportation. Google Street View was used to survey the built environment variables. Regression modeling was then utilized to establish a relationship between intersection crash clusters and the built environment. The results show that commercial/institutional land uses, bus stops, and signalized intersections are statistically significant and have a positive impact on intersection crash incidence. Additionally, crash incidences were higher in neighborhoods with below-average income percentages. These findings potentially can enlighten policymakers to focus on appropriate safety treatments such as traffic-calming measures and identify areas where traffic safety policies need to be prioritized. Policy re-evaluation for bus stop locations and design ideas for the urban form could be established to reduce motor vehicle intersection crashes.