Study Details

Study Title: Corridor-level signalized intersection safety analysis in Shanghai, China using Bayesian hierarchal models

Authors: Kun Xie, Xuesong Wang, Helai Huang, Xiahong Chen

Publication Date: JAN, 2013

Abstract: Most traffic crashes in Chinese cities occur at signalized intersections. Research on the intersection safety problem in China is still in its early stage. The recent development of an advanced traffic information system in Shanghai enables in-depth intersection safety analyses using road design, traffic operation, and crash data. In Shanghai, the road network density is relatively high and the distance between signalized intersections is small, averaging about 200 m. Adjacent signalized intersections located along the same corridor share similar traffic flows, and signals are usually coordinated. Therefore, when studying intersection safety in Shanghai, it is essential to account for intersection correlations within corridors. In this study, data for 195 signalized intersections along 22 corridors in the urban areas of Shanghai were collected. Mean speeds and speed variances of corridors were acquired from taxis equipped with Global Positioning Systems (GPS). Bayesian hierarchical models were applied to identify crash risk factors at both the intersection and the corridor levels. Results showed that intersections along corridors with lower mean speeds were associated with fewer crashes than those with higher speeds, and those intersections along two-way roads, under elevated roads, and in close proximity to each other, tended to have higher crash frequencies.

Study Citation: Xie, K., X. Wang, H. Huang, X. Chen, "Corridor-level signalized intersection safety analysis in Shanghai, China using Bayesian hierarchal models." Accident Analysis and Prevention 50(2013), 25-33

Study Report: Download the Study Report Document


CMFs Associated With This Study

Category: Intersection geometry

Countermeasure: Presence of an elevated road above intersection

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
1.58 -58 2 Stars All All Not specified Urban

Countermeasure: Presence of three leg intersection vs. four leg intersection

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.75 25 2 Stars All All Not specified Urban

Category:Roadway

Countermeasure: Convert from two-way to one-way traffic

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.53 47 2 Stars All All Not specified Urban