BACKGROUND

The 2016 AASHTO Manual for Assessing Safety Hardware (MASH) provides full-scale test matrices for evaluating cable median barriers on level terrain and sloped median ditches. The matrices define the critical placement of cable barriers and test criteria for 4:1 (horizontal to vertical slope) and 6:1 V-ditches to evaluate the safety performance of cable median barriers. Recent full-scale crash testing of cable median barriers under the conditions described in MASH Test No. 3-16 have produced varying results for the stability of small vehicles traversing 4:1 V-ditches.

MASH Test No. 3-16 uses a 46-ft-wide V-ditch as measured from slope break point to slope break point, with the cable barrier test article placed 4 ft from the slope break point on the far side of the V-ditch. However, small vehicles have experienced inconsistent stability while traversing the 4:1 V-ditches during crash testing, and the AASHTO Roadside Design Guide (RDG) notes that 4:1 V-ditches are not a preferred configuration for median V-ditches. This raises concerns that the traversability of the V-ditch configuration used in MASH 2016 may be near the limit of vehicle stability.

Research is needed to investigate the traversability of 4:1 V-ditches to verify if the current configuration specified in MASH Test No. 3-16 produces sufficient vehicle stability for consistent and reliable test article impact conditions.

OBJECTIVE

The objective of this research is to investigate the traversability of 4:1 V-ditches for crash testing of cable median barrier systems.

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

TASKS

Task descriptions are intended to provide a framework for conducting the research. The NCHRP is seeking the insights of proposers on how best to achieve the research objective. Proposers are expected to describe research plans that can realistically be accomplished within the constraints of available funds and contract time. Proposals must present the proposers' current thinking in sufficient detail to demonstrate their understanding of the issues and the soundness of their approach to meeting the research objective.

PHASE I – Planning

Task 1. Conduct a literature review of relevant research and other sources regarding the traversability of 4:1 V-ditches and other 4:1 ditch geometries with a focus on the traversal behaviors and trajectory of the MASH 1100C vehicle, but also considering the 1500A and 2270P test vehicles. The review shall include published and unpublished research conducted through the NCHRP; the Federal Highway Administration (FHWA); and other national, international, state, and pooled fund sponsored research.

Task 2. Review state department of transportation (DOT) standards, the RDG, MASH, and other published guidelines regarding 4:1 ditch geometries.

Task 3. Synthesize and summarize the results of Tasks 1 and 2. Define the knowledge gaps relevant to the project objective that will be addressed in this research. Document the findings of 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:

• Define ditch traversability and vehicle stability prior to impacts with cable barrier for consistent and repeatable crash test results
• Determine evaluation criteria to meet the definitions of ditch traversability and vehicle stability
• Determine critical factors and their effects on 4:1 V-ditch traversability and vehicle stability associated with
  • soil conditions
  • ditch width
  • vehicle trajectory
  • vehicle parameters
  • other relevant factors identified by the researcher
• Investigate the performance differences between 4:1 V-ditches and 4:1 round bottom and 4:1 flat bottom ditches
• Verify if the 4:1 V-ditch configuration specified in MASH is traversable in a consistent manner for full-scale testing using simulation and physical testing (physical testing may or may not require a test article, i.e., cable barrier)

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.

Following a 1-month review of Interim Report No. 1 by the NCHRP project panel, the research team will meet in person with the panel to discuss the interim report. For budgeting purposes, the proposer shall plan on having the in-person panel meeting in Washington, DC. Costs for the in-person meeting venue and travel costs for NCHRP panel members to attend the meeting will be paid separately by the NCHRP. 

Work on Phase II of the project will not begin until authorized by the NCHRP.

PHASE II – Method Development

Task 6. Execute the method in the approved Interim Report No.1 except for modeling, simulation, and physical testing. Provide an updated plan for modeling, simulation, and physical testing to verify that the 4:1 V-ditch configuration specified in MASH is traversable based on the findings/feedback of the method. Summarize findings in a technical memorandum and participate in a virtual meeting to debrief the NCHRP panel.

Task 7. Execute modeling and simulation. Document findings in a technical memorandum and participate in a virtual meeting to debrief the NCHRP panel. If needed, revise the physical testing plan. NCHRP approval is required before physical testing in Task 8 can begin.

Task 8. Execute physical testing. Document findings in a technical memorandum.

Task 9. Validate and, if necessary, refine the definitions for ditch traversability and vehicle stability. Determine if the 4:1 V-ditch configuration specified in MASH is acceptable. Based on the validation results, develop a stand-alone document with the refined definitions and MASH language for AASHTO consideration and other supporting materials (hereafter called AASHTO deliverables). This resulting language may be considered by AASHTO for the next updates of MASH and the RDG.

Task 10. Develop an outreach plan to gather feedback from the AASHTO Technical Committee on Roadside Safety (TCRS), the TRB Committee on Roadside Design, or a similar industry group with a minimum of one presentation, to be executed in Phase III. The presentation(s) and other activities in the outreach plan shall be hosted and coordinated by the research team.

Task 11. Prepare Interim Report No. 2, which documents the results of Tasks 6 through 10 and provides an updated work plan for the remainder of the project.

Note: Following a 1-month review of Interim Report No. 2 by the NCHRP project panel, the research team will meet with the panel in a virtual format to discuss the interim report.

Work on Phase III of the project will not begin until authorized by the NCHRP.

PHASE III – Final Deliverables

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

Task 13. Revise the AASHTO deliverables. The AASHTO deliverables are due at least 6 months before the contract end date.

Task 14. 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 distinctly illustrates for the audience how the research can be applied in their organization;
• Supporting data files, including photos and videos; and
• A technical memorandum titled “Implementation of Research Findings and Products” (see Special Note J).

Note: Following receipt of the draft final deliverables, the remaining 3 months shall be for NCHRP review and comment and for research agency preparation of the final deliverables.

SPECIAL NOTES

A. The Information and Instructions for Preparing Proposals for the Transportation Research Board’s Cooperative Research Programs were revised in May 2024. Please take note of the new and revised text which is highlighted in yellow.

B. Proposals must be submitted as a single PDF file with a maximum file size of 10 MB. The PDF must be formatted for standard 8 ½” X 11” paper, and the entire proposal must not exceed 60 pages (according to the page count displayed in the PDF). Proposals that do not meet these requirements will be rejected. For other requirements, refer to chapter V of the instructions.

C. The Information and Instructions for Preparing Proposals for the Transportation Research Board’s Cooperative Research Programs have been modified to include a revised policy and instructions for disclosing Investigator Conflict of Interest. For more information, refer to chapter IV of the instructions. A detailed definition and examples can be found in the CRP Conflict of Interest Policy for Contractors. The proposer recommended by the project panel will be required to submit an Investigator Conflict of Interest and Disclosure Form as a prerequisite for contract negotiations.

D. Proposals will be rejected if any of the proposed research team members work for organizations represented on the project panel. The panel roster for this project can be found at https://www.mytrb.org/OnlineDirectory/Committee/Details/7097. Proposers may not contact panel members directly; this roster is provided solely for the purpose of avoiding potential conflicts of interest.

E. Proprietary Products - If any proprietary products are to be used or tested in the project, please refer to Item 6 in the Information and Instructions for Preparing Proposals.

F. Proposals are evaluated by the NCHRP staff and project panels consisting of individuals collectively knowledgeable in the problem area. The project panel will recommend their first choice proposal considering the following factors: (1) the proposer's demonstrated understanding of the problem; (2) the merit of the proposed research approach and experiment design; (3) the experience, qualifications, and objectivity of the research team in the same or closely related problem area; (4) the plan for ensuring application of results; (5) how the proposer approaches inclusion and diversity in the composition of their team and research approach, including participation by certified Disadvantaged Business Enterprises; and, if relevant, (6) the adequacy of the facilities. A recommendation by the project panel is not a guarantee of a contract. The National Academy of Sciences (NAS - the contracting authority for the National Academies of Sciences, Engineering, and Medicine) will conduct an internal due diligence review and risk assessment of the panel’s recommended proposal before contract negotiations continue.

Note: The proposer's approach to inclusion and diversity as well as participation by Disadvantaged Business Enterprises should be incorporated in Item 11 of the proposal.

G. Copyrights - All data, written materials, computer software, graphic and photographic images, and other information prepared under the contract and the copyrights therein shall be owned by the National Academy of Sciences. The contractor and subcontractors will be able to publish this material for non-commercial purposes, for internal use, or to further academic research or studies with permission from TRB Cooperative Research Programs. The contractor and subcontractors will not be allowed to sell the project material without prior approval by the National Academy of Sciences. By signing a contract with the National Academy of Sciences, contractors accept legal responsibility for any copyright infringement that may exist in work done for TRB. Contractors are therefore responsible for obtaining all necessary permissions for use of copyrighted material in TRB's Cooperative Research Programs publications. For guidance on TRB's policies on using copyrighted material please consult Section 5.4, "Use of Copyrighted Material," in the Procedural Manual for Contractors.

H. The text of the final deliverable is expected to be publication-ready when it is submitted. It is strongly recommended that the research team include the expertise of a technical editor as early in the project timeline as possible. See Appendix F of the Procedural Manual for Contractors Conducting Research in the Transportation Research Board’s Cooperative Research Program for technical editing standards expected in final deliverables.

I. Proposals should include a task-by-task breakdown of labor hours for each staff member as shown in Figure 4 in the Information and Instructions for Preparing Proposals. Proposals also should include a breakdown of all costs (e.g., wages, indirect costs, travel, materials, and total) for each task using Figures 5 and 6 in the brochure. Please note that TRB Cooperative Research Program subawards (selected proposers are considered subawards to the National Academy of Sciences, the parent organization of TRB) must comply with 2 CFR 200 – Uniform Administrative Requirements, Cost Principles, and Audit Requirements for Federal Awards. These requirements include a provision that proposers without a "federally" Negotiated Indirect Costs Rate Agreement (NICRA) shall be subject to a maximum allowable indirect rate of 10% of Modified Total Direct Costs. Modified Total Direct Costs include all salaries and wages, applicable fringe benefits, materials and supplies, services, travel, and up to the first $25,000 of each lower tier subaward and subcontract. Modified Total Direct Costs exclude equipment, capital expenditures, charges for patient care, rental costs, tuition remission, scholarships and fellowships, participant support costs and the portion of each lower tier subaward and subcontract in excess of $25,000.

J. The required technical memorandum titled “Implementation of Research Findings and Products” should (a) provide recommendations on how to best put the research findings/products into practice; (b) identify possible institutions that might take leadership in applying the research findings/products; (c) identify issues affecting potential implementation of the findings/products and recommend possible actions to address these issues; and (d) recommend methods of identifying and measuring the impacts associated with implementation of the findings/products. Implementation of these recommendations is not part of the research project and, if warranted, details of these actions will be developed and implemented in future efforts.

The research team will be expected to provide input to an implementation team consisting of panel members, AASHTO committee members, the NCHRP Implementation Coordinator, and others in order to meet the goals of NCHRP Active Implementation: Moving Research into Practice, available at http://onlinepubs.trb.org/onlinepubs/nchrp/docs/NCHRP_ActiveImplementation.pdf

K. If the team proposes a Principal Investigator who is not an employee of the Prime Contractor, or if the Prime Contractor is proposed to conduct less than 50% of the total effort (by time or budget), then section five of the proposal should include: (1) a justification of why this approach is appropriate, and (2) a description of how the Prime Contractor will ensure adequate communication and coordination with their Subcontractors throughout the project.

L. All budget information should be suitable for printing on 8½″ x 11″ paper. If a budget page cannot fit on a single 8½″ x 11″ page, it should be split over multiple pages. Proposers must use the Excel templates provided in the Information and Instructions for Preparing Proposals for the Transportation Research Board’s Cooperative Research Programs.

M. The National Academies have an ethical and legal obligation to provide proper attribution whenever material from other sources is included in its reports, online postings, and other publications and products. TRB will review all Cooperative Research Programs draft final deliverables using the software iThenticate for potential plagiarism. If plagiarized text appears in the draft final deliverable, the research team will be required to make revisions and the opportunity to submit future proposals may be affected.

N. All physical tests must be performed by laboratories accredited to ISO 17025:2017 and be within the laboratory’s scope of accreditation.