Application of partial proportional odds model for analyzing pedestrian crash injury severities in Switzerland

According to the Swiss Microcensus, Switzerland is a place where people choose to walk more than 40% of their daily trip time, resulting in a higher pedestrian crash to total crash ratio when compared to many other developed countries. Furthermore, the high number of old and young pedestrians as well as the large number of pedestrian crashes with higher levels of severity makes the pedestrian crash analysis for Switzerland very important. This study aims to identify the important factors that influence the injury severity levels of pedestrian-vehicle crashes in Switzerland. To address this we employ a partial proportional odds model to analyze pedestrian crash injury severities in Switzerland, based on the 5-year (2008-2012) pedestrian safety data. The study also focuses on a separate analysis for two vulnerable groups of pedestrians (young and old pedestrians) to examine the change in the influence of factors over age. The analysis involves an extensive evaluation based on pedestrian and driver characteristics; main reason for the crash; traffic, temporal, vehicle, roadway geometric and environmental characteristics. The study shows that irrespective of age, dark unlighted areas, sight obstructions, midblock crossings and heavy vehicles adversely affect the injury severity levels of pedestrians.