TRB’s National Cooperative Highway Research Program (NCHRP) Report 638: Guidelines for Guardrail Implementation explores guidance on selecting the appropriate barrier performance level for the installation of longitudinal barriers.
The following appendices to NCHRP Report 638 are only available online. • Appendix A, Guardrail Use Guidelines for Benefit/Cost = 2 • Appendix B, Guardrail Use Guidelines for Benefit/Cost = 3 • Appendix C, Guardrail Use Guidelines for Benefit/Cost = 4 • Appendix D, Guardrail Use Guidelines for Benefit/Cost = 1