Bayesian approach to model pedestrian crashes at signalized intersections with measurement errors in exposure. (December 2018)

• Record Type: Journal Article
• Authors: Xie, S.Q.; Dong, Ni; Wong, S.C.; Huang, Helai; Xu, Pengpeng
• Is Part Of: Accident analysis and prevention. Volume 121(2018)
• Page Start: 285
• Page End: 294
• Publication Date: 2018-12
• Subjects: Pedestrian crash frequency -- Signalized intersections -- Pedestrian exposure -- Measurement errors; Accidents -- Prevention -- Periodicals; Accident Prevention -- Periodicals; Accidents -- Prévention -- Périodiques; 363.106
• DOI: 10.1016/j.aap.2018.09.030
• Languages: English
• ISSNs: 0001-4575

Abstract

Highlights: A measurement error model was developed to analyze pedestrian crash counts. The presence of uncertainties in pedestrian and vehicle volumes was confirmed. The omission of pedestrian volume would lead to biased and incorrect inferences. The presence of exclusive signals would reduce pedestrian crash risks by 45%. Abstract: This study intended to identify the potential factors contributing to the occurrence of pedestrian crashes at signalized intersections in a densely populated city, based on a comprehensive dataset of 898 pedestrian crashes at 262 signalized intersections during 2010–2012 in Hong Kong. The detailed geometric design, traffic characteristics, signal control, built environment, along with the vehicle and pedestrian volumes were elaborately collected. A Bayesian measurement errors model was introduced as an alternative method to explicitly account for the uncertainties in volume data. To highlight the role played by exposure, models with and without pedestrian volume were estimated and compared. The results indicated that the omission of pedestrian volume in pedestrian crash frequency models would lead to reduced goodness-of-fit, biased parameter estimates, and incorrect inferences. Our empirical analysis demonstrated the existence of moderate uncertainties in pedestrian and vehicle volumes. Six variables were found to have a significant association with the number of pedestrian crashes at signalized intersections. The number of crossing pedestrians, the number of passing vehicles, the presence of curb parking, and the presence of ground-floor shops were positively related with pedestrian crash frequency, whereas the presence of playgrounds near intersections had a negative effect on pedestrian crash occurrences. Specifically, the presence of exclusive pedestrian signals for all crosswalks was found to significantly reduce the risk of pedestrian crashes by 43%. The present study is expected to shed more light on a deeper understanding of the environmental determinants of pedestrian crashes.