Study Details
Study Title: Safety Evaluation of the Safety Edge Treatment
Authors: Graham et al.
Publication Date:MAR, 2011
Abstract: Between periods of maintenance, pavement-edge drop-offs can form along the edge of highways. When a driver runs off the roadway, such drop-offs can hinder reentry and may lead to driver overcorrection, loss of control, or overturning on the roadway or roadside. The safety edge is a treatment that is implemented in conjunction with pavement resurfacing and is intended to help minimize drop-off-related crashes. This report examines the safety effects, costs, and benefits of this low-cost treatment for two-lane and multilane rural highways. The safety research was conducted as an observational before-after evaluation of treated sites using the empirical Bayes method. The economic appraisal consisted of a benefit-cost analysis. The safety evaluation found that the safety edge treatment appears to have a small positive crash reduction effect. The best effectiveness measure for the safety edge treatment was a 5.7 percent reduction in total crashes on rural two-lane highways. However, this result was not statistically significant. The economic analysis showed that the treatment is very inexpensive and that its application is highly cost-effective for a broad range of conditions on two-lane highways. Inconsistent results were found for rural multilane highways due to a small data sample.
Study Citation: Graham, J.L., Richard, K.R. , O'Laughlin, M.K., Harwood, D.W., "Safety Evaluation of the Safety Edge Treatment" Report No. FHWA-HRT-11-024, Federal Highway Administration, Washington, DC. (2011)
Study Report: Download the Study Report Document
CMFs Associated With This Study
Category: Shoulder treatments
Countermeasure: Install safety edge treatment
CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
---|---|---|---|---|---|---|
0.948 | 5.16 | Run off road | O | Principal Arterial Other | Rural |
0.798 | 20.225 | Run off road | O | Principal Arterial Other | Rural |
0.885 | 11.524 | Run off road | O | Principal Arterial Other | Rural |
1.035 | -3.538 | Run off road | O | Principal Arterial Other | Rural |
1.312 | -31.229 | Run off road | O | Principal Arterial Other | Rural |
1.129 | -12.878 | Run off road | O | Principal Arterial Other | Rural |
0.926 | 7.374 | Run off road | O | Principal Arterial Other | Rural |
0.84 | 16.029 | Run off road | O | Principal Arterial Other | Rural |
0.898 | 10.162 | Run off road | O | Principal Arterial Other | Rural |
0.897 | 10.293 | Other | All | Principal Arterial Other | Rural |
0.909 | 9.13 | Other | All | Principal Arterial Other | Rural |
0.934 | 6.603 | Other | All | Principal Arterial Other | Rural |
0.912 | 8.759 | Other | All | Principal Arterial Other | Rural |
1.796 | -79.564 | Other | All | Principal Arterial Other | Rural |
1.197 | -19.733 | Other | All | Principal Arterial Other | Rural |
0.874 | 12.586 | Other | All | Principal Arterial Other | Rural |
0.955 | 4.455 | Other | All | Principal Arterial Other | Rural |
0.944 | 5.587 | Other | All | Principal Arterial Other | Rural |
0.849 | 15.135 | Other | K,A,B,C | Principal Arterial Other | Rural |
1.184 | -18.357 | Other | K,A,B,C | Principal Arterial Other | Rural |
1.052 | -5.202 | Other | K,A,B,C | Principal Arterial Other | Rural |
0.575 | 42.488 | Other | K,A,B,C | Principal Arterial Other | Rural |
0.615 | 38.503 | Other | K,A,B,C | Principal Arterial Other | Rural |
0.63 | 36.972 | Other | K,A,B,C | Principal Arterial Other | Rural |
0.784 | 21.596 | Other | K,A,B,C | Principal Arterial Other | Rural |
1.052 | -5.23 | Other | K,A,B,C | Principal Arterial Other | Rural |
0.953 | 4.676 | Other | K,A,B,C | Principal Arterial Other | Rural |
0.975 | 2.55 | Other | O | Principal Arterial Other | Rural |
0.794 | 20.631 | Other | O | Principal Arterial Other | Rural |
0.892 | 10.829 | Other | O | Principal Arterial Other | Rural |
1.026 | -2.553 | Other | O | Principal Arterial Other | Rural |
2.317 | -131.652 | Other | O | Principal Arterial Other | Rural |
1.41 | -40.967 | Other | O | Principal Arterial Other | Rural |
0.947 | 5.319 | Other | O | Principal Arterial Other | Rural |
0.921 | 7.89 | Other | O | Principal Arterial Other | Rural |
0.956 | 4.435 | Other | O | Principal Arterial Other | Rural |
0.923 | 7.732 | All | All | Principal Arterial Other | Rural |
0.886 | 11.361 | All | All | Principal Arterial Other | Rural |
0.932 | 6.817 | All | All | Principal Arterial Other | Rural |
0.845 | 15.524 | All | All | Principal Arterial Other | Rural |
1.269 | -26.942 | All | All | Principal Arterial Other | Rural |
1.002 | -0.235 | All | All | Principal Arterial Other | Rural |
0.905 | 9.485 | All | All | Principal Arterial Other | Rural |
0.935 | 6.516 | All | All | Principal Arterial Other | Rural |
0.943 | 5.674 | All | All | Principal Arterial Other | Rural |
0.89 | 10.959 | All | K,A,B,C | Principal Arterial Other | Rural |
1.156 | -15.555 | All | K,A,B,C | Principal Arterial Other | Rural |
1.06 | -5.982 | All | K,A,B,C | Principal Arterial Other | Rural |
0.55 | 44.993 | All | K,A,B,C | Principal Arterial Other | Rural |
0.565 | 43.548 | All | K,A,B,C | Principal Arterial Other | Rural |
0.591 | 40.939 | All | K,A,B,C | Principal Arterial Other | Rural |
0.835 | 16.528 | All | K,A,B,C | Principal Arterial Other | Rural |
1.064 | -6.361 | All | K,A,B,C | Principal Arterial Other | Rural |
0.983 | 1.667 | All | K,A,B,C | Principal Arterial Other | Rural |
0.974 | 2.554 | All | O | Principal Arterial Other | Rural |
0.757 | 24.281 | All | O | Principal Arterial Other | Rural |
0.868 | 13.201 | All | O | Principal Arterial Other | Rural |
0.934 | 6.579 | All | O | Principal Arterial Other | Rural |
1.509 | -50.902 | All | O | Principal Arterial Other | Rural |
1.129 | -12.894 | All | O | Principal Arterial Other | Rural |
0.962 | 3.845 | All | O | Principal Arterial Other | Rural |
0.872 | 12.795 | All | O | Principal Arterial Other | Rural |
0.929 | 7.1 | All | O | Principal Arterial Other | Rural |
0.863 | 13.721 | Run off road | All | Principal Arterial Other | Rural |
0.909 | 9.08 | Run off road | All | Principal Arterial Other | Rural |
0.921 | 7.872 | Run off road | All | Principal Arterial Other | Rural |
0.918 | 8.183 | Run off road | All | Principal Arterial Other | Rural |
1.469 | -46.895 | Run off road | All | Principal Arterial Other | Rural |
1.135 | -13.484 | Run off road | All | Principal Arterial Other | Rural |
0.858 | 14.177 | Run off road | All | Principal Arterial Other | Rural |
0.952 | 4.786 | Run off road | All | Principal Arterial Other | Rural |
0.937 | 6.315 | Run off road | All | Principal Arterial Other | Rural |
0.808 | 19.175 | Run off road | K,A,B,C | Principal Arterial Other | Rural |
1.181 | -18.058 | Run off road | K,A,B,C | Principal Arterial Other | Rural |
1.036 | -3.609 | Run off road | K,A,B,C | Principal Arterial Other | Rural |
0.537 | 46.332 | Run off road | K,A,B,C | Principal Arterial Other | Rural |
1.125 | -12.464 | Run off road | K,A,B,C | Principal Arterial Other | Rural |
0.836 | 16.402 | Run off road | K,A,B,C | Principal Arterial Other | Rural |
0.769 | 23.123 | Run off road | K,A,B,C | Principal Arterial Other | Rural |
1.2 | -20.037 | Run off road | K,A,B,C | Principal Arterial Other | Rural |
1.026 | -2.622 | Run off road | K,A,B,C | Principal Arterial Other | Rural |