Study Details
Study Title: Safety effects of wider edge lines on rural, two-lane highways
Authors: Park et al.
Publication Date:SEP, 2012
Abstract: Although it is generally expected that wider lines will have a positive effect on vehicle safety, there have not been any convincing evidence based on the crash data analysis, partly because of the lack of relevant data. In this paper, the safety effect of wider edge lines was examined by analyzing crash frequency data for road segments with and without wider edge lines. The data from three states, Kansas, Michigan, and Illinois, have been analyzed. Because of different nature of data from each state, a different statistical analysis approach was employed for each state: an empirical Bayes, before-after analysis of Kansas data, an interrupted time series design and generalized linear segmented regression analysis of Michigan data, and a cross sectional analysis of Illinois data. Although it is well-known that causation is hard to establish based on observational studies, the results from three extensive statistical analyses all point to the same findings. The consistent findings lend support to the positive safety effects of wider edge lines installed on rural, two-lane highways.
Study Citation: Park, E.S., P.J. Carlson, R.J. Porter, and C.K. Anderson. "Safety effects of wider edge lines on rural, two-lane highways". Accident Analysis and Prevention Vol. 48, (2012) pp. 317-325.
Interim results (not included in the CMF Clearinghouse) were published in a TTI report (Miles, D.M., Carlson, P.J., Eurek, R., Re, J., and Park, E.S., "Evaluation of Potential Benefits of Wider and Brighter Edge Line Pavement Markings." FHWA/TX-10/0-5862-1 Texas Transportation Institute, Texas Department of Transportation, July 2010.)
Additionally, these findings will be published (TBD) in a final report for FHWA.
CMFs Associated With This Study
Category: Delineation
Countermeasure: Install wider edgelines (4 in to 5 in)
CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
---|
0.623 | 37.7 | | All | K,A,B,C | Not specified | Rural |
0.64 | 36 | | Day time | K,A,B,C | Not specified | Rural |
0.643 | 35.7 | | Nighttime,Wet road | All | Not specified | Rural |
0.63 | 37 | | Single vehicle | All | Not specified | Rural |
0.672 | 32.8 | | Single vehicle,Wet road | All | Not specified | Rural |
0.705 | 29.5 | | Nighttime,Single vehicle | All | Not specified | Rural |
0.578 | 42.2 | | Single vehicle | K,A,B,C | Not specified | Rural |
0.637 | 36.3 | | Nighttime,Single vehicle | K,A,B,C | Not specified | Rural |
Countermeasure: Install wider edgelines (4 in to 6 in)
CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
---|
0.73 | 27 | | Single vehicle | All | Not specified | Rural |
0.632 | 36.8 | | Single vehicle | K,A,B,C | Not specified | Rural |
0.816 | 18.4 | | Nighttime,Single vehicle | All | Not specified | Rural |
0.813 | 18.7 | | Nighttime,Single vehicle | K,A,B,C | Not specified | Rural |
0.81 | 19 | | Fixed object | All | Not specified | Rural |
0.757 | 24.3 | | Nighttime,Wet road | All | Not specified | Rural |
0.77 | 23 | | Day time | K,A,B,C | Not specified | Rural |
0.88 | 12 | | Day time | All | Not specified | Rural |
0.341 | 65.9 | | Single vehicle,Wet road | All | Not specified | Rural |
0.82 | 18 | | Nighttime,Single vehicle | All | Not specified | Rural |
1.019 | -1.9 | | Single vehicle | K,A,B,C | Not specified | Rural |
0.208 | 79.2 | | Nighttime,Wet road | All | Not specified | Rural |