BACKGROUND
Roadside safety hardware (RSH) such as guardrail is crash tested to assess the crashworthiness of the device. The current crash test criteria are contained in the AASHTO Manual for Assessing Safety Hardware (MASH), and all state departments of transportation (DOTs) are in the process of implementing MASH hardware on their systems. While MASH-tested hardware is available for the majority of applications, state DOTs and other transportation agencies may encounter situations where the approved RSH is not suitable for the location.
Transportation agencies may address these situations with special site-specific designs; however, no specific documentation of such practices is currently available, nor are guidelines on how transportation agencies should address these situations. Some examples of non-standard roadside applications could include modifying a crash-tested barrier to fit a location, using an older crash test standard, using less stringent testing criteria, and shielding or not shielding some obstacles at a location. Research is needed to develop guidelines for non-standard RSH applications where standard practices for crash-tested RSH cannot be used.
OBJECTIVES
The objectives of this research are the following:
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Identify strategies for situations where MASH system designs may not be practical, such as environmental constraints, right-of-way limitations, and utility conflicts.
RESEARCH TASKS
Task 1. Review literature and develop a survey for transportation agencies and practitioners. Resources consulted should include extant state DOT guidelines on practice and other resources such as crash data, full-scale crash test data, computer simulations, and in-service performance evaluation data. Develop a survey for transportation agencies and other practitioners to gather information on situations where standard MASH devices for specific roadway criteria could not be accommodated and what alternate mitigations were considered and implemented. The survey shall determine (a) situations that agencies are encountering, their prevalence, and design context/conditions; (b) how agencies addressed these situations; and (c) other pertinent references or research.
Task 2. Conduct a survey and prepare work plan for Task 4.
Task 2a. Conduct a survey of transportation agencies and other practitioners. Synthesize the survey results and prioritize situations identified in the survey.
Task 2b. Prepare a work plan with recommendations for situations that should be investigated in Task 4. Include a proposed methodology for how these strategies would be investigated and what the products of the investigation might be. Investigation elements might include simulation, risk-based analysis, and dynamic testing.
Task 3. Submit an interim report summarizing the findings of Tasks 1-2. Present findings to NCHRP at an interim meeting with the project panel. NCHRP approval of the interim report is required before work on remaining tasks may begin. The interim meeting may be held in-person at the Keck Center in Washington, D.C. NCHRP will be responsible for the meeting facility and travel costs for the panel members to attend the meeting.
Task 4. Conduct an investigation of strategies identified in Task 2 and develop draft guidelines.
Task 4a. Conduct an investigation of strategies identified in Task 2.
Task 4b. Develop draft guidelines for use by transportation agencies and practitioners. Guidelines shall include a process for assessing situations and selecting appropriate mitigation strategies for these situations. Draft guidelines shall be referred to NCHRP for review and comments at intervals during the course of Task 4. Present the complete set of guidelines to the panel at an online meeting. NCHRP approval of the guidelines is required before work on Task 5 may begin.
Task 5. Submit a final report summarizing Tasks 1-4. The final report should include the guidelines developed in Task 4.
STATUS: Research in Progress.
