Study Details
Study Title: Developing Crash Modification Factors for Guardrails, Utility Poles, and Side-Slope Improvements
Authors: Avelar et al.
Publication Date:AUG, 2021
Abstract: Through this project, researchers evaluated the safety effects of guardrails, utility poles, and side slopes using safety data from Indiana and Pennsylvania. Safety evaluations in this project focused on total, fatal-and-injury, and roadway-departure crash risk. Crash modification factors (CMFs) and benefit–cost (B/C) ratios were developed for the safety improvements (guardrails, utility poles, and side slopes) of interest. The CMFs for protecting utility poles with guardrails were not statistically significant for total and roadway-departure crashes (CMF values were 0.89 and 1.52, depending on how close the utility poles were to the roadway). The CMFs for fatal-and-injury crashes were statistically significant (CMFs of 0.524 and 0.433, depending on pole proximity to the roadway). Results for CMFs developed for pole removal in terms of fatal-and-injury crashes indicated a statistically significant CMF of 0.656. For pole relocation, this evaluation found a statistically significant CMF of 0.866 on total crashes. Finally, estimated CMFs for side-slope flattening indicated reductions in total and roadway-departure crashes. The statistically significant CMFs varied between 0.923 and 0.936 for total crashes and between 0.784 and 0.951 for roadway-departure crashes, depending on the initial and final flattened-slope values. The economic evaluation of guardrails indicated that guardrail implementations are economically viable when protecting roadside utility poles (a B/C ratio of 1.28 or 1.48). The economic evaluation of pole removal or relocation indicated that this strategy is economically viable when not considering the acquisition of new right-of-way (a B/C ratio of 6.73).
Study Citation: Avelar, R., K. Dixon, S. Ashraf, and AS. Jhamb. "Developing Crash Modification Factors for Guardrails, Utility Poles, and Side-Slope Improvements." Report No. FHWA-HRT-21-075. Federal Highway Administration. McLean, Virginia. (August 2021).
Related Citations: Tech Brief. "Developing Crash Modification Factors for Guardrails, Utility Poles, and Side-Slope Improvements." Report No. FHWA-HRT-21-076. Federal Highway Administration. McLean, Virginia.
CMFs Associated With This Study
Category: Roadside
Countermeasure: Flatten side slopes
CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
---|
0.8699 | 13.01 | | Other | All | All | Rural |
Countermeasure: Protect Side Slopes with Guardrails
CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
---|
1.044 | -4.4 | | Other | All | All | Rural |
Countermeasure: Protect Utility Poles with Guardrails
CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
---|
1.38 | -38 | | Other | All | All | Rural |
Countermeasure: Remove/Relocate Utility Poles
CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
---|
1.3375 | -33.75 | | Other | All | All | Rural |