01663020

Component

Safety performance functions (SPFs) identify crash contributing factors and identify crash hotspots for the purpose of safety improvements. The U.S. Highway Safety Manual (HSM) provides a series of SPFs for various roadway facilities, developed using data from multiple states. In states without local jurisdiction-based SPFs, it is common practice to adopt national SPFs for crash prediction and safety improvement. However, the HSM SPFs transfer work has not been conducted to China where the traffic safety analysis is in its initial phase. With the foundation of U.S. traffic safety work, this study therefore aims to investigate the transferability of HSM SPFs to China, and how they might be improved to be transferred to China. Using the road design, traffic volume, and crash data of four-leg signalized intersections, four-lane and multi-lane (6-10 lanes) divided urban arterials in the downtown areas of Orlando, Florida, and Shanghai, SPFs were developed separately for the two cities using negative binomial models. Pooled datasets were further created by combining different proportions of Shanghai samples into Orlando samples to estimate SPFs. A transfer index was estimated using log-likelihood to evaluate the transferability of the SPFs. Results showed that the separate SPFs were not transferable between the two cities. Pooled data consisting of all Orlando samples and 50% of Shanghai samples made SPFs for four-leg signalized intersections and multi-lane road segments on urban arterials transferable to Shanghai, and when the proportion of Shanghai samples increased to 75% in the pooled data, SPFs for four-lane divided road segments also became transferable. Recommendations for better general SPF transferability to China are suggested.

This paper was sponsored by TRB committee ANB25 Standing Committee on Highway Safety Performance.

18-04325

English

6p

2018

Transportation Research Board 97th Annual Meeting

Digital/other

References (10) ; Tables

Arterial highways; Crash causes; Crash data; High risk locations; Traffic volume; Urban highways

Safety Performance Functions

Orlando (Florida); Shanghai (China)

Highways; Safety and Human Factors

Transportation Research Board Annual Meeting 2018 Paper #18-04325

TRIS, TRB, ATRI

Jan 8 2018 11:04AM