The National Academies

NCHRP 25-69 [Pending]

Guide to Increasing and Sustaining Native Flora in Roadside Vegetation

  Project Data
Funds: $375,000
Contract Time: 24 months
Staff Responsibility: Michael Brooks


Many state departments of transportation (DOTs) have struggled to manage roadside vegetation in a cost-effective manner that also fosters vigorous and diverse native plant communities, including blooming species. Diverse vegetation on roadsides can support operational, environmental, and social values, including valuable pollinator habitat and other ecosystem services. A 2019 Nebraska study (NDOT Roadside Vegetation Establishment and Management) highlights the need to balance ecological, operational, and cost concerns. Research is needed to better understand and develop practical, environmentally responsible strategies to increase and sustain native plant diversity in roadside vegetation. This research should examine relevant factors such as soil conditions, plant species selection, seed quality, herbicide application, and scenic value.   


The objective of this project is to develop a guide for state DOTs to maintain safe, efficient, and cost-effective vegetation diversity practices. At a minimum, the guide should provide a summary of suggested practices and resources for state DOTs tied to climatic/ecologic regions, and should be supported by a field use document.


PHASE I: Planning and Initial Outreach

Task 1. Conduct a review of the most relevant literature and related resources. The review should include appropriate species, approaches, site preparation, seeding methods, seed mixes and rates, weed control in sites with existing vegetation, soil conditions, and costs associated with varying courses of action. 

Task 2. Design a survey of state DOTs and other pertinent organizations. The survey should include current practices, areas of concern, roadside safety practices, agency goals and values, public perception of vegetation practices, known successful and challenging plant species, seed quality and quantity, and the status of any field trials. The survey design should also address the need for targeted interviews. Submit a technical memorandum summarizing Tasks 12 for NCHRP approval. Approval is required before work on subsequent tasks may begin. 

Task 3. Conduct a survey of state DOTs and other organizations. As needed, conduct targeted interviews of subject-matter experts. 

Task 4. Propose a method to achieve the research objective, to be fully developed in Phase II. At a minimum: 

  • Discuss differences in regional approaches to vegetation diversity practices
  • Present tests for a range of strategies that encourage roadside vegetation diversity
  • Design the guide to (1) enable decision-making at various lifecycle stages (e.g., establishment, preservation, enhancement) and site conditions, and (2) facilitate updates to the guide and field use document using future research findings
  • Discuss the need for further outreach
  • Provide an annotated outline for the proposed guide
  • Describe the data to be collected for the field use document and the document's intended users

Task 5. Prepare an interim report that documents Tasks 1 through 4 and provides an updated work plan for the remainder of the research. The updated plan must describe the process and rationale for the work proposed for Phase II.


PHASE II: Execute the Method and Produce Final Deliverables

Task 6. Execute the research method from Task 4 according to the approved interim report.

Task 7. Develop the guide and field use document. The draft guide and field survey tool shall be submitted no later than 6 months before the contract end date.

Task 8. Prepare the final deliverables, which shall include the following:

  • The research report that documents the entire research effort
  • The guide and field use document 
  • An executive memorandum emphasizing high-order benefits and opportunity costs discovered during the research, with emphasis on agency mission and values
  • Public outreach materials: presentations, graphics, and press releases
  • A standalone technical memorandum entitled “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.

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