Study Details

Study Title: Crash Modification Factors for High-Tension Cable Median Barriers in Pennsylvania

Authors: Gayah et al.

Publication Date:JUN, 2023

Abstract: The objective of this project was to develop a suite of crash modification factors (CMFs) to quantify the safety impacts of installing high-tension cable median barriers (HTCMBs) on freeway segments within the Commonwealth of Pennsylvania. An empirical Bayes observational before-after study was performed to develop CMFs for this countermeasure. The analysis revealed that the installation of HTCMBs was associated with increases in total, fatal + injury, property-damage-only, and hit-barrier crash frequencies. With the exception of the total fatal and injury crash type, the results were statistically significant. The results are consistent with engineering expectations because, when an object (longitudinal barrier) is placed adjacent to the traveled way, it is expected that run-off-road crashes will increase because the barrier limits the lateral distance for a vehicle to recover. However, the installation of HTCMBs was associated with statistically significant decreases in cross-median, fatal + A injury (i.e., suspected serious injury), and cross-median fatal + A injury crash frequencies. These results were also consistent with engineering expectations, as the longitudinal barrier is intended to mitigate severe crashes resulting from vehicles crossing the median and colliding with vehicles traveling in the opposite direction.

Study Citation: Gayah, V., E.T. Donnell, A. Prajapati, and H. Liu. " Crash Modification Factors for High-Tension Cable Median Barriers in Pennsylvania" Report No. PennDOT-2023-ECMS-E04834-WO14. The Pennsylvania Department of Transportation. Harrisburg, Pennsylvania. (June 2023).


CMFs Associated With This Study

Category: Roadside

Countermeasure: Install cable median barrier (high tension)

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
1.133-13.35 StarsAllAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
1.031-3.14 StarsAllK,A,B,CPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
1.202-20.25 StarsAllOPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
2.835-183.55 StarsOtherAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
0.20979.15 StarsCross medianAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
0.65834.24 StarsAllK,APrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
0.10189.94 StarsCross medianK,APrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
1.111-11.15 StarsAllAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysUrban
1.022-2.24 StarsAllK,A,B,CPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysUrban
1.187-18.75 StarsAllOPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysUrban
2.698-169.85 StarsOtherAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysUrban
0.17882.25 StarsCross medianAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysUrban
0.61395 StarsAllK,APrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysUrban
0.13986.14 StarsCross medianK,APrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysUrban
1.205-20.55 StarsAllAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysRural
1.06-65 StarsAllK,A,B,CPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysRural
1.251-25.15 StarsAllOPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysRural
3.416-241.64 StarsOtherAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysRural
0.29714 StarsCross medianAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysRural
0.81718.34 StarsAllK,APrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysRural
1.094-9.45 StarsAllAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
1.02-25 StarsAllK,A,B,CPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
1.159-15.95 StarsAllOPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
3.133-213.35 StarsOtherAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
0.19980.15 StarsCross medianAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
0.61738.35 StarsAllK,APrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
0.07692.4Cross medianK,APrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
1.198-19.85 StarsAllAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
1.063-6.35 StarsAllK,A,B,CPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
1.273-27.35 StarsAllOPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
2.308-130.84 StarsOtherAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
0.18981.14 StarsCross medianAllPrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
0.69530.54 StarsAllK,APrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll
0.10889.24 StarsCross medianK,APrincipal Arterial Interstate, Principal Arterial Other Freeways and ExpresswaysAll