BACKGROUND

Roadside design guidance typically instructs agencies to limit fixed objects, including trees, along roadways to provide a safer recovery area for errant vehicles. On urban streets, trees are amenities that benefit pedestrians, bicyclists, residents, and others by providing shade, heat reduction, potential traffic calming and speed reductions, air and water quality benefits, and aesthetic appeal.  However, trees are fixed objects that can cause serious injury or fatality if struck by an errant vehicle.

NCHRP Project 17-82, “Proposed Guidance for Fixed Objects in the Roadside Design Guide” explored crash prediction methods and developed design guidelines regarding trees and utility poles in rural non-freeway settings. On roadways with posted speed limits of 30 mph and less, trees are generally accepted as part of the roadside environment. At posted speed limits of 55 mph and greater, facilities for non-motorized users are less likely to be present and vehicular collisions with trees have the potential to result in serious injuries or fatalities. However, research is needed for urban and suburban roadways, particularly in posted speed limit settings between 35 and 50 mph. On these roadways, vehicle collisions with trees are a significant safety concern; however, maximizing properly and sustainably designed tree placements in the roadside environment can benefit public health and community livability.

Research is needed to help state departments of transportation (DOTs) and other transportation agencies advance the knowledge on the safety effects of trees and support guidelines to inform tree planning and landscaping policies, procedures, and practices that support the needs of all roadway users.

OBJECTIVE

The objective of this research is to develop a practitioner’s guide for evaluating the safety effects of trees on urban and suburban roadways with a focus on posted speed limits of 35 to 50 mph.

The practitioner’s guide will include a framework for the sustainable placement, maintenance, removal, and replanting of trees and complementary features in roadway environments. This research will consider the needs of all users of the transportation system and support implementation of the Safe System approach.

Accomplishment of the project objective(s) 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, literature, and other sources regarding trees in the roadside environment, related to the project objective, including livability and effects on all transportation system users. 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, county, and local tree-related policies and practices in urban and suburban settings from diverse geographic areas, climates, and contexts within the United States.

Task 3.  Conduct a critical analysis and synthesis of the Tasks 1 and 2 results and identify knowledge gaps and opportunities related to the project objective. These gaps must be addressed in the final deliverables if the budget allows or in the recommended future research. Document findings from Tasks 1 through 3 in a technical memorandum.

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

• Determine what effect trees, based on their presence and characteristics (e.g., size, placement, canopy) have on vehicle operating speeds and non-motorized transportation system users (e.g., pedestrians and cyclists);
• Evaluate the safety effects, both positive and negative (e.g., crash frequency, type, and severity), related to trees in the roadside environment;
• Identify and analyze roadway context characteristics at tree crash sites that resulted in fatalities or serious injuries (e.g., presence of on-street bike facilities, lighting, roadside barriers, tree density, proximity to travel lanes);
• Identify tree characteristics (e.g., size, habit, family, canopy, maintenance) that may impact the frequency and severity of crashes;
• Evaluate the safety effects of stewardship and tree maintenance policies (e.g., pruning and inspection programs); and
• Conduct a comparative analysis of the frequency, type, and severity of crashes on roadways with trees to similar roadways without trees and identify trends and risk factors (e.g., traffic volume, intersections, curves, medians).

The method shall include the proposer’s approach to collecting and analyzing data, and if practicable, an approach for presenting research findings at posted speed limits increments within the range.

Task 5. Prepare an annotated outline of the draft practitioner’s guide.

Task 6. Prepare Interim Report No. 1, which documents Tasks 1 through 5 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 7. Collect data and refine approaches for analyses. Summarize refinements and data collection processes in a technical memorandum.

Task 8. Execute methods in the approved Interim Report No. 1 and as refined in Task 7. Provide a summary of results and an approach to how the results will be incorporated into the practitioner’s guide in a technical memorandum.

Task 9. Develop the draft practitioner’s guide with supporting graphics.

Task 10. Develop an outreach plan that includes at least one in-person workshop that is 1.5 days long hosted by the contractor with at least 15 participants, including a potential attendees’ list with representatives from state DOTs and other practitioners with diverse viewpoints. The outreach plan will include workshop materials and a draft attendee list.

Note: The contractor shall be responsible for (1) preparing all background and presentation material (background material may include pre-recorded material) and (2) all arrangements for the in-person workshop(s) (including securing meeting facilities, lodging, and transportation for participants; reimbursing participants for incurred related travel expenses; facilitating; and recording discussions during the workshops, etc.).

Task 11. Develop draft materials for a webinar suitable to explain the guide and its contents to practitioners. Include a plan for dissemination and potential participants.

Task 12. Prepare Interim Report No. 2, which documents Tasks 7 through 11 and provides an updated work plan for the remainder of the research.

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 13. Execute the outreach plan in the approved Interim Report No. 2.  NCHRP will approve the final list of attendees. Summarize findings in a technical memorandum.

Task 14. Refine the draft guide based on input from outreach efforts in Task 13.

Task 15. Refine the draft webinar materials based on the results from Task 14.

Task 16. Organize, coordinate, and deliver the webinar. (The webinar’s recording and presentation with the presenter’s notes will be part of the final deliverables.) NCHRP will approve the final list of webinar attendees.

Task 17. Prepare final deliverables, including:

• A practitioner’s guide;
• A conduct of research report, including an executive summary, that documents all research and project efforts;
• 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;
• A 90-minute recorded webinar with presentation notes; 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/7082. 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.