BACKGROUND

New federal and state requirements increasingly tie greenhouse gas (GHG) evaluation to transportation decision-making. The Carbon Reduction Program, established under the Bipartisan Infrastructure Law, requires state departments of transportation (DOTs) and metropolitan planning organizations (MPOs) to develop carbon reduction strategies to support the reduction of transportation emissions. The Federal Highway Administration promulgated a GHG Transportation Performance Management measure that would require state DOTs and MPOs to set decreasing targets for transportation emissions on the National Highway System. In addition, a growing number of states, including Colorado and Minnesota, have adopted planning standards that require DOTs and MPOs to evaluate and reduce GHG emissions from transportation projects. These programming changes occur within the context of an evolving transportation field, adapting to technological trends such as the deployment of artificial intelligence and the increasing availability of big data-driven models. 

Recent research efforts including NCHRP WebResource 1: Reducing Greenhouse Gas Emissions: A Guide for State DOTs and NCHRP WebResource 3: GHG Emissions and Climate Change in Environmental Reviews have examined GHG emissions practices at the planning and environmental review stages. Research is needed to understand the current deployment of tools as related to the effects of transportation investments on GHG emissions and the capabilities and limitations of these tools to develop recommendations for improvement and provide suggestions for new tools.

OBJECTIVES

The objectives of this project are to develop (1) a guide to help DOTs and MPOs to evaluate the capabilities and limitations of existing tools for estimating the effects of transportation investments on GHG emissions and (2) a research roadmap providing recommendations to advance the state of the practice. At minimum, the research will: 

• Ascertain the current state of GHG emission analysis practices.
• Evaluate the utility of existing assumptions, including land-use impacts, fleet turnover, the effects of induced demand, and other factors.
• Prioritize the most consequential gaps in current emission analysis practice.
• Suggest effective practices for transparent model validation in evaluating the effectiveness of existing tools.
• Provide suggestions for the development of new tools.   

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

TASKS

PHASE I: Planning and Initial Outreach

Task 1. Conduct a review of literature, tools, and resources used for evaluating the effects of transportation investments on GHG emissions. 

Task 2. Develop a stakeholder outreach plan. The outreach should target practitioners and subject matter experts from state DOTs, MPOs, academic institutions, policy organizations, and other relevant organizations. The plan will detail the strategy for eliciting participant feedback on practices, limitations, and desired improvements on current models. The plan should also consider lessons learned from outreach efforts for earlier associated projects. Submit technical memorandum #1 including the results of Task 1 and the plan developed in Task 2. NCHRP approval of technical memorandum #1 is required before work on subsequent tasks may begin.

Task 3. Administer and summarize the stakeholder outreach. Submit technical memorandum #2 summarizing the results of the stakeholder outreach. NCHRP approval of technical memorandum #2 is required before work on subsequent tasks may begin.

Task 4. Examine the available validation and analysis of relevant GHG evaluation tools and methodologies, focusing on the capabilities and limitations of available resources.

Task 5. Propose a method to achieve the research objective to be fully developed in Phase II. At minimum, the method will include:

• An appraisal of the current state of GHG emission analysis practices.
• An evaluation of capabilities and limitations of current practice.
• An evaluation of existing assumptions and prioritization of the most consequential gaps in current practices at the planning and pre-engineering stages, including the interdependencies of differing models and strategies.
• Suggested best practices for transparent validation of analytical models and tools.
• An annotated outline of a guide and roadmap to further advance the state of the practice. 

Task 6. Prepare Interim Report No. 1 that documents Tasks 1 through 5 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 7. Execute the research method according to the approved Interim Report No.1.

Task 8. Develop the guide and research roadmap. The draft guide and research roadmap shall be submitted for NCHRP approval no later than 6 months before the contract end date.

Task 9. Conduct a follow-on stakeholder outreach effort, with the goal of eliciting practitioner feedback on the draft deliverables. Summarize the outreach in an online debrief with NCHRP, including any recommended changes to the deliverables. Any proposed changes must be approved by NCHRP.

Task 10. Prepare the draft final deliverables, which shall include the following:

• A conduct of research report that documents the entire research effort.
• The final guide and research roadmap.
• Public outreach materials, including a PowerPoint presentation with speaker notes.
• 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.