Hot Spot Analysis

Pedestrian or bicycle safety problems may be revealed by examining locations with dense concentrations of reported pedestrian or bicycle crashes on and near a campus. Dense concentrations of crashes are called "hot spots." A simple version of hot spot analysis assigns all reported crashes in an area to the closest intersection or roadway segment. The intersections with the highest number of crashes are identified as hot spots, and roadway segments with the highest number of crashes per mile are identified as hot spots. Geographic information systems (GIS) can also be used to identify hot spots (Schneider, Khattak, and Zegeer 2001). Once crash locations are geocoded, a spatial analysis procedure can be used to calculate the density of crashes. The procedure creates a raster image representing the density of crashes around each cell, and the highest cell density values indicate hot spots.

UC Berkeley Campus periphery reported bicycle crash density. Source: Schneider et al. (2012). Pedestrian and Bicycle Safety Strategies for UC Berkeley Campus and Periphery: Recommendations for Implementation.

UC Berkeley Campus periphery reported bicycle crash density.
Source: Schneider et al. (2012). Pedestrian and Bicycle Safety Strategies for UC Berkeley Campus and Periphery: Recommendations for Implementation.

Considerations: Since crashes reported to the police only represent a portion of all pedestrian or bicycle incidents, the reported-crash hot spots do not reveal problem locations that have high numbers of unreported crashes. Also, in general, locations with more pedestrian or bicycle activity tend to experience higher numbers of pedestrian and bicycle crashes. Since hot spots are typically based on the number of crashes in a particular location (rather than the rate of crashes per pedestrian or bicyclist), they often highlight locations with high pedestrian and bicycle volumes but overlook locations that may be risky but have lower pedestrian and bicycle volumes.

Applications: This approach has been applied at the University of California, Berkeley (see below) and several other campuses.

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