Portland State University. Department of Civil & Environmental Engineering
Christopher M. Monsere
Term of Graduation
Date of Publication
Master of Science (M.S.) in Civil & Environmental Engineering
Civil and Environmental Engineering
1 online resource (ix, 58 pages)
Bicycling is becoming increasingly popular in Oregon and the US in general due to its environment friendliness as well as health benefits. With Oregon's population projected to increase by more than 30% over the next 30 years, improving the safety of the transportation network for persons on bicycles is important. In Oregon, majority of the bicyclist crashes occur at intersections. This thesis seeks to identify the determinant factors that significantly impact bicyclist crash injury severity at intersections. A mixed logit framework that accounts for any unobserved heterogeneity in the data and allows the estimated parameters to randomly vary across observations was applied to three years of bicyclist crash data (2016-2018) with a total of 1502 categorized crashes in Oregon at both unsignalized and signalized intersections. This work reports the relative risk of bicyclist injury severity instead of the absolute injury risk in a bicyclist crash.
As part of identifying the significant determinant factors, a parameter transferability test is done to determine that the two types of intersection need to be modeled separately. A total of fourteen variables were found to be significant at unsignalized intersections. Wearing a helmet reduces the probability of slight injury while urban area, winter season, and bicyclists with age 10 or younger have higher chance of slight injury. Clear weather, male bicyclists, speeding, presence of traffic control device, and non-motorist being on a bike lane at intersection have increased likelihood of non-incapacitating injury while crash year 2018 shows lower probability of this injury level. In terms of injury severity, bicyclists of age 65 or older, use of alcohol, and angled collision are associated with high risk for incapacitating and fatal injuries and evening peak hours reduces the likelihood of this injury type.
The mixed logit model for crash analysis at signalized intersections found eight significant variables impacting bicyclist crash severity. Using helmet, bicyclists in the age range 26-35 years, spring season, and clear weather lead to decreased likelihood of slight injury; however, driver's failure to yield right of way increases the probability of slight injury. Crashes occurring at cross-signalized intersections have lower probability of non-incapacitating injuries. Speeding-involved crashes significantly increase the chance of incapacitating and fatal injuries and bicyclists traveling straight is associated with lower risk for incapacitating/fatal injuries. Based on these findings, several countermeasures to improve bicyclist safety are recommended.
© 2021 Apy Das
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Das, Apy, "Determinant Factors of Bicyclist Injury Severity at Signalized and Unsignalized Intersections" (2021). Dissertations and Theses. Paper 5871.
Available for download on Wednesday, November 09, 2022