A Spatiotemporal Exploratory Analysis of Assault Crimes Near Portland's TriMet Public Transportation Network

Abstract

Portland’s public transportation system, TriMet, is an extensive network of buses, light rail, and streetcars. Millions of passengers ride on the transit system every year. Likewise, each year thousands of people are victims of violent crimes in public spaces throughout the city. A geospatial analysis of assault crimes may offer law enforcement an invaluable tool for examining the spatial patterns of assaults. This project is a spatiotemporal exploratory analysis of assault crime near transit nodes in Portland, Oregon. The analysis calculates location quotients for aggravated assaults, simple assaults, and intimidation assaults at the macro, meso and micro levels. Location quotients measure the concentration of each offense type in buffered areas around transit nodes relative to the surrounding area at each level of the analysis. Location quotients at the macro level for each offense type in each year of the study period were between 2.4 and 2.8, indicating assault crime concentrations were approximately two and a half times to nearly three times higher in areas within 500 feet of the transit system throughout the entire city. The results of the macro analysis suggest that a spatial relationship exists between Portland’s public transportation network and locations of assault crimes. Results of the meso and micro levels varied considerably between neighborhoods and intersections, suggesting other underlying factors should be studied.