A Comprehensive Study on Pavement Edge Line Implementation

The previous 2011 study “Safety Improvement from Edge Lines on Rural Two-Lane Highways” analyzed the crash data of three years before and one year after edge line implementation by using the latest safety analysis statistical method. It concluded that placing pavement edge lines on rural two-lane highways in Louisiana can not only change the lateral positions of the vehicles but also reduce crashes. The Crash Modification Factor (CMF) for edge line on narrow, rural two-lane highways is 0.78. Considering the decreasing trend in crashes in the state for the past three years, the modified CMF is 0.83, which implies that, on average, implementing edge lines can reduce 17% of crashes. As an extension of the 2011 project, this study not only used two more years of crash data for the after time period but also applied the Empirical Bayes (EB) method in the analysis to estimate the crash reduction factors. Moreover, crash characteristics analysis is performed in this study to compare the difference before and after edge line implementation. Additionally, this project performed benefit and cost analysis. By considering the safety trend in Louisiana, the final estimated CMF is 0.85, which means there is a 15% expected crash reduction in edge line implementation on narrow, rural two-lane highways. The statistically estimated standard deviation for the CMF is 0.039. The crash reduction is consistent in all crash types and particularly significant in single vehicle crashes. Most of single vehicle crashes are run-off-road (ROR) crashes, which is the exact type of crash targeted by edge line implementation. The benefits overwhelmingly offset the cost with edge line implementation. The most conservative estimation for benefit and cost ratio is 19. This project recommends the use of edge lines on narrow rural two-lane highways whenever it is financially feasible and operationally feasible.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; References; Tables;
  • Pagination: 71p

Subject/Index Terms

Filing Info

  • Accession Number: 01526335
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/LA.13/508
  • Contract Numbers: LTRC Project Number: 13-2P; SIO Number: 30000730
  • Created Date: May 6 2014 9:56AM