Identifying High-Risk Built Environments for Severe Bicycling Injuries

PI: Qing Shen (UW), qs@u.washington.edu
Dates:  12/16/2015 – 12/15/2016
Status: Completed
UTC Project Information
Final Technical Report

The rise of eco-friendly lifestyles has contributed to the increasing popularity of bicycling in the US. However, cyclist crash injuries remain as a serious public health problem. While the number of deaths in traffic crashes has declined significantly over the past four decades (The National Highway Traffic Safety Administration 2012a), the number of injured cyclists increased from 45,000 in 2001 to 49,000 in 2012. The percentage of cyclist fatalities among total traffic deaths increased from 1.7% to 2.2% in the same period (The National Highway Traffic Safety Administration 2012b). Thus, it is important to understand what factors are associated with cyclist injuries, especially severe injuries.

While human behavioral factors have been widely investigated as likely causes to cyclist injuries, the exploration of the relationship between built environment and cyclist injury severity is at the initial stage for three reasons. First, built environment factors are typically perceived as indirectly associated with cyclist injury severity, and are either treated as confounders or ignored. Secondly, existing studies of cyclist injury severity tend to overlook cities that have relatively few cyclists, and the variations of cycling risk in different cities that have different levels of bicycling and different built environments for bicycling have not been analyzed. Thirdly, current studies focus primarily on addressing the safety concerns of riding on different types of bicycle infrastructure, while insufficiently examining land use variables and other road design features. This proposed research is aimed at advancing our understanding of the effects of built environment factors on cyclist injury severity by addressing the following three questions:

1)            Are built environment and cyclist injury severity correlated? If so, what built environment factors most significantly and importantly contribute to severe bicycling injuries?

2)            Are the identified statistical associations varied significantly among cities with different levels of bicycling and different built environments?

3)            Are the identified statistical associations different for bicycle crashes that involve no motor vehicle?