Citation

Qin X, Chen Z, Shaon RR. J. Transp. Saf. Secur. 2019; 11(6): 629-641.

Copyright

(Copyright © 2019, Southeastern Transportation Center, and Beijing Jiaotong University, Publisher Informa - Taylor and Francis Group)

DOI

10.1080/19439962.2018.1458052

PMID

unavailable

Abstract

Transportation agencies rely on the Highway Safety Manual's (HSM) scientific predictive procedures to quantify road safety; however, the HSM methods may not be accurate for use by local jurisdictions. This study used data from rural two-lane, two-way intersections in South Dakota to compare jurisdiction-specific safety performance functions (SPFs) and HSM SPFs to determine which functions were more accurate when used locally. Jurisdiction-specific SPFs--without the use of a calibration factor--were found to be most accurate. The study also compared fixed severity proportion with a severity proportion function calibrated by local data. The authors assumed that the site-specific severity proportion would be more appropriate than a fixed value because the former reflects the relationship between severity proportion and site characteristics. However, results showed that the severity proportion function did not contribute significantly to prediction accuracy. The conclusion offers certain level of assurance for practitioners who are more likely to use a fixed injury severity proportion as a viable alternative to a site-specific severity proportion.

Language: en

Keywords

Highway Safety Manual; rural two-lane two-way intersections; safety performance functions; severity proportion function