Ranking Cities for Safety Investigation by Potential for Safety Improvement

Numerous methods have been proposed in the past to conduct the identification of hotspots (HSID). However, most of them are dedicated to the micro-level analysis such as roadway segments and intersections. Very limited studies are focused on the HSID of more aggregate levels, which in general have larger sample means and wider dispersion in the collision counts. The authors performed a city-level HSID by using the four-year data of 265 cities in California. It is intended to equip road safety professionals with more useful tools to compare the safety performance of city as a whole. Potential for Safety Improvement (PSI) was adopted as a measure of crash risk to compare alternate HSID methods, including the Empirical Bayes (EB) and three full Bayesian (FB) alternatives, Negative-Binomial (FBNB), Poisson Log-Normal (FBPLN), and the Poisson Temporal Random Effect (FBPTRE), for ranking the safety performance of cities. Five evaluation tests which contain the Site Consistency Test, the Method Consistency Test, the Total Rank Difference Test, the Total Performance Difference Test and the Total Score Test were applied to evaluate the performance of the four HSID methods. Moreover, two cutoff levels, top 5% and 10% cities, were employed for more reliable results. Overall, the study results are consistent with the results of previous quantitative evaluations focused on micro-level HSID. The three FB approaches significantly outperform the EB counterpart. The method accounting for temporal random effect produces more reliable HSID results than those without considering the serial correlations in collision counts.

• Supplemental Notes:
  • This paper was sponsored by TRB committee ANB10 Transportation Safety Management.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Cheng, Wen
  • Jiang, Ximiao
  • Lin, Wei Hua
  • Jia, Xudong
  • Wu, Xinkai
  • Zhou, Jiao
• 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: Web
• Features: Figures; References; Tables;
• Pagination: 22p
• Monograph Title: TRB 94th Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Cities; Crash characteristics; Crash rates; Crash risk forecasting; High risk locations; Highway safety; Intersections; Mathematical models; Risk analysis
• Geographic Terms: California
• Subject Areas: Data and Information Technology; Highways; Safety and Human Factors; I81: Accident Statistics; I82: Accidents and Transport Infrastructure;

Filing Info

• Accession Number: 01556841
• Record Type: Publication
• Report/Paper Numbers: 15-4422
• Files: TRIS, TRB, ATRI
• Created Date: Mar 12 2015 3:19PM