01664226

Component

Safety performance functions (SPFs) are statistical regression models used for estimating crash counts by roadway facility classification. They are required in the identification of high frequency crash locations, the process of assessing the effectiveness of safety countermeasures provided for hazardous crash sites in before-and-after analyses and comparison of road designs in terms of safety. Roadway agencies may opt to develop jurisdiction specific SPFs or borrow them from the national Highway Safety Manual (HSM) provided by the American Association of State Highway and Transportation Officials. In addition, the HSM suggests a simple technique to calibrate its SPFs to specific jurisdictions. A more recent calibration technique is similar to that of the HSM with a minor modification, also known as the calibration function. In this research, the authors develop SPFs of total crashes for rural divided multilane highway segments in four states. The states are Florida, Ohio, California and Washington. The authors also calibrate each SPF to all states using the HSM calibration method and the calibration function. Furthermore, the authors propose the use of the K nearest neighbor data mining method for calibrating SPFs. According to the goodness of fit results, the authors' proposed calibration method is superior to the HSM’s and the calibration function.

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

18-00658

English

15p

2018

Transportation Research Board 97th Annual Meeting

Digital/other

References; Tables

Calibration; Divided highways; Multilane highways; Rural highways

Highway Safety Manual

K-nearest neighbor algorithm; Safety performance functions

California; Florida; Ohio; Washington (State)

Highways; Safety and Human Factors

Transportation Research Board Annual Meeting 2018 Paper #18-00658

TRIS, TRB, ATRI

Jan 8 2018 10:10AM