BACKGROUND

The American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) provides criteria for full-scale crash testing and evaluation of roadside safety hardware (RSH) devices. As part of an RSH assessment, MASH requires that an RSH device be evaluated at its critical impact point (CIP), critical impact angle (CIA), or both, depending on the device category. The CIP or CIA is defined as the point or angle that maximizes the potential for failure of the device based on structural loading, vehicle stability, vehicle snagging, or other considerations.

While MASH has specific guidance for determining CIPs for several types of barriers (such as post-and-beam longitudinal barriers), CIP or CIA guidance is more general or nonexistent for many classes of RSH devices. In these cases, MASH recommends that CIP and CIA be determined by computer simulation. However, not all test laboratories have computer simulation capabilities, and MASH recognizes that using computer simulation solely to determine CIPs is often not practical. Even if computer simulation is used for this purpose, MASH does not detail what factors to consider in the CIP analysis. The limited procedures for determining critical impact conditions for these safety devices and tests has led to differences in how devices are tested and evaluated at different laboratories. This may result in inconsistent test results.

Research is needed to support state departments of transportation (DOTs) in establishing crash-test procedures for assessing RSH devices in a uniform and consistent manner.

OBJECTIVE

The project objective is to develop and validate procedures to determine CIPs and CIAs to assess the crashworthiness of RSH devices. The project will focus on RSH devices that currently have a range or limited criteria to determine CIPs and CIAs.

Accomplishment of the project objective will require at least the following tasks.

TASKS

PHASE I – Planning

Task 1. Conduct a literature review of relevant research regarding CIPs and CIAs. The review shall include published and unpublished research and procedures from the NCHRP; the Federal Highway Administration (FHWA); and other national, international, state, private sector, and pooled fund sponsored research.

Task 2. Develop and execute an outreach plan to assess the current state of the practice for determining CIPs and CIAs. Any outreach materials and distribution lists must be approved by the NCHRP before distribution.

Task 3. Synthesize and summarize the results of Tasks 1 and 2. Identify knowledge gaps and opportunities related to the project objective. Provide a summary of priority needs identified in Tasks 1 and 2. Document Tasks 1 through 3 in a technical memorandum.

Task 4. Develop a method to achieve the project objective, to be executed in Phase II. At a minimum, the method shall formulate strategies to:

• Identify MASH tests with a range or limited criteria for CIPs and CIAs.
• Develop criteria to rank MASH tests for developing procedures to determine CIPs and CIAs
• Rank and recommend MASH tests to develop procedures to determine CIPs and CIAs
• Determine hardware, hardware installation, and vehicle parameters that influence critical impact conditions for each selected category of RSH
• Develop procedures to determine CIPs and CIAs with the selected tests (these procedures should remain applicable as the parameters that influence critical impact conditions change)
• Develop procedures to conduct sensitivity analyses for CIPs and CIAs
• Validate the procedures. The validation method may use information from
  • Previous crash tests (including failed tests)
  • New crash tests (if necessary)
  • Other available data, including manufacturer information
  • Modeling and simulation

Task 5. Prepare Interim Report No. 1, which documents Tasks 1 through 4 and provides an updated work plan for the remainder of the research.

PHASE II – Method Execution

Task 6. Execute the method in the approved Interim Report No.1, excluding validation. Provide an updated validation plan. Summarize findings in a technical memorandum and participate in a virtual meeting to debrief the NCHRP panel.

Task 7. Execute the validation. Revise procedures as needed.

Task 8. Develop an outreach plan to gather industry feedback on Tasks 6 and 7 that includes at least one in-person workshop and one virtual workshop, both hosted by the contractor, with at least 15 participants at each workshop representing diverse viewpoints, including testing laboratories, RSH manufacturers, and DOTs. The workshops will be held in Phase III.

Task 9. Develop draft materials for a webinar that are suitable for explaining procedures to MASH users. Include a plan for dissemination of draft materials and a list of potential participants.

Task 10. Prepare Interim Report No. 2, which documents the results of Tasks 6 through 9 and provides an updated work plan for the remainder of the project.

PHASE III – Final Deliverables

Task 11. Develop a stand-alone document with draft language for AASHTO consideration to incorporate the research results in the next update of MASH (hereafter called "AASHTO deliverables"). The AASHTO deliverables are due at least 6 months before the contract end date.

Task 12. Execute the outreach plan per the approved Interim Report No. 2. Summarize activities and findings in a technical memorandum.

Task 13. Refine the draft webinar materials based on the results of Tasks 11 and 12. Revise the AASHTO deliverables based on the findings of Task 12 as approved by the NCHRP.

Task 14. Organize, coordinate, and deliver the webinar. (The webinar’s recording, presentation, and presenter’s notes will be part of the final deliverables.) The NCHRP will approve the final list of webinar attendees.

Task 15. Prepare final deliverables, including:

• A research report, including an executive summary, that documents all research, findings, and project efforts
• The AASHTO deliverables
• A PowerPoint presentation with speaker notes that summarizes the project and illustrates for the audience how the research can be applied in their organization
• A 90-minute recorded webinar suitable for explaining the procedures to MASH users
• Supporting data files, including photos and videos
• A technical memorandum titled “Implementation of Research Findings and Products”.

STATUS: Proposals have been received in response to the RFP. The project panel will meet to select a contractor to perform the work.