The variety of median widths and terrains combined with evolving testing specifications and lack of conclusive data on median crossover crashes have been obstacles to developing median barrier guidance.
The TRB National Cooperative Highway Research Program's NCHRP Research Report 996: Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers develops, in a format suitable for consideration and possible adoption by AASHTO, proposed guidelines for the selection and placement of Manual for Assessing Safety Hardware (MASH) Test Levels 2 through 5 (TL2-TL5) median barriers.
National Research Council. 2022. Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers. Washington, DC: The National Academies Press. https://doi.org/10.17226/26679.
|Chapter 1 - Introduction||1-1|
|Chapter 2 - Definitions||2-2|
|Chapter 3 - Literature Review||3-32|
|Chapter 4 - Methodology||33-40|
|Chapter 5 - Guidelines||41-56|
|Chapter 6 - Conclusions||57-58|
|Appendix A - Survey of States||65-72|
|Appendix B - Probability of Reaching the Lateral Offset of Feature j PY(Yj)||73-108|
|Appendix C - Probability of Crash Severity (PSEVj)||109-144|
|Appendix D - Probability of Passing Through, Over, or Under a Barrier (THRBAR)||145-152|
|Appendix E - Probability of Passing Across the Opposing Lanes (THREOL)||153-172|
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