Development of Crash Modification Factors of Alignment Elements and Safety Countermeasures for Korean Freeways

Recently, many efforts have been devoted to improving the safety of freeways in Korea, as freeways are the most important roadways in the transportation network. As a part of these efforts, this research aims to develop crash modification factors (CMFs) of two alignment elements, as well as eight safety countermeasures for Korean freeways. To do this, classical safety performance functions (SPFs) for each freeway were developed. To develop the CMFs of two alignment elements, horizontal curve and vertical grade, the authors also estimated inclusive SPFs that include the alignment elements together with traffic volume and segment length as independent variables. The CMFs of horizontal curve and vertical grade were calculated as the marginal effect of their coefficients on the inclusive SPFs. Then, eight CMFs for safety countermeasures including delineator posts, automated speed enforcement cameras, rumble strips, chevron signs, roadside barriers, grooving, illumination and median barriers were developed. The regression-to-the-mean (RTM) bias, time trend of crash count, and effect of traffic volume change were corrected by using the empirical Bayes (EB) method. The developed CMFs in this study were compared with those from previous literature and discussed the findings from the comparison. The results from this study contribute to enhancing the safety of Korean freeways and act as a reference guide for other Korean roadways, as well as roadways in other countries.

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• Supplemental Notes:
  • This paper was sponsored by TRB committee ANB25 Highway Safety Performance.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Choi, Yoon-Young
  • Kho, Seung-Young
  • Lee, Chungwon
  • Kim, Dong-Kyu
• Conference:
  • Transportation Research Board 94th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2015-1-11 to 2015-1-15
• Date: 2015

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; Photos; References; Tables;
• Pagination: 18p
• Monograph Title: TRB 94th Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Barriers (Roads); Crash causes; Highway curves; Highway grades; Highway safety; Infrastructure; Rumble strips; Safety equipment; Traffic control devices
• Geographic Terms: Korea
• Subject Areas: Highways; Safety and Human Factors; I85: Safety Devices used in Transport Infrastructure;

Filing Info

• Accession Number: 01550141
• Record Type: Publication
• Report/Paper Numbers: 15-0503
• Files: PRP, TRIS, TRB, ATRI
• Created Date: Jan 16 2015 8:29AM