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(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
---|
1.133 | -13.3 | | All | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
1.031 | -3.1 | | All | K,A,B,C | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
1.202 | -20.2 | | All | O | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
2.835 | -183.5 | | Other | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
0.209 | 79.1 | | Cross median | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
0.658 | 34.2 | | All | K,A | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
0.101 | 89.9 | | Cross median | K,A | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
1.111 | -11.1 | | All | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | Urban |
1.022 | -2.2 | | All | K,A,B,C | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | Urban |
1.187 | -18.7 | | All | O | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | Urban |
2.698 | -169.8 | | Other | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | Urban |
0.178 | 82.2 | | Cross median | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | Urban |
0.61 | 39 | | All | K,A | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | Urban |
0.139 | 86.1 | | Cross median | K,A | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | Urban |
1.205 | -20.5 | | All | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | Rural |
1.06 | -6 | | All | K,A,B,C | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | Rural |
1.251 | -25.1 | | All | O | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | Rural |
3.416 | -241.6 | | Other | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | Rural |
0.29 | 71 | | Cross median | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | Rural |
0.817 | 18.3 | | All | K,A | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | Rural |
1.094 | -9.4 | | All | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
1.02 | -2 | | All | K,A,B,C | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
1.159 | -15.9 | | All | O | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
3.133 | -213.3 | | Other | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
0.199 | 80.1 | | Cross median | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
0.617 | 38.3 | | All | K,A | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
0.076 | 92.4 | | Cross median | K,A | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
1.198 | -19.8 | | All | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
1.063 | -6.3 | | All | K,A,B,C | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
1.273 | -27.3 | | All | O | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
2.308 | -130.8 | | Other | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
0.189 | 81.1 | | Cross median | All | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
0.695 | 30.5 | | All | K,A | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |
0.108 | 89.2 | | Cross median | K,A | Principal Arterial Interstate, Principal Arterial Other Freeways and Expressways | All |