Analyzing Pedestrian and Bicyclist Crashes at the Corridor Level: Structural Equation Modeling Approach

Pedestrian and bicycle crashes have been increasing at an alarming pace in recent years. Between 2009 and 2016, annual U.S. pedestrian fatalities increased 46%, and bicyclist fatalities increased 34%. Crashes involving pedestrians and bicyclists, or vulnerable road users (VRUs), are negatively correlated with roadway factors, and positively correlated with environmental and socioeconomic factors. However, specific variables representing these factors are often correlated, making it difficult to accurately characterize relationships between individual variables and pedestrian and bicyclist safety. This study used the structural equation model technique to overcome this problem. Pedestrian and bicyclist crash frequency and more than 60 explanatory variables for 200 highway corridors in Wisconsin were collected. The interrelationships between observed manifest variables and unobserved latent variables were tested. The results suggest that the most important latent variables influencing the crash frequency of VRUs are bicycle/pedestrian-oriented roadway design (e.g., paved shoulders, sidewalks, and bike lanes), exposure (e.g., walking and biking activity, and employment density), and low social status (e.g., educational level, and wage percentage). The benefits of this study may help community planners, transportation researchers, and policymakers with a better understanding of the intricate interrelationship of the influential factors contributing to VRUs road crashes.