Incorporating Greenhouse Gas Emissions Into the Collaborative Decision-Making Process

In the last few years, scientific consensus has strengthened around the fact that the emission of greenhouse gases (GHGs) into the atmosphere is contributing to changes in the earth's climate. While uncertainty remains over the pace and dimensions of the change, a consensus around the need for action has grown among the public and elected officials. In part, this shift has been accelerated by concern over energy security and rising fuel prices. The new political landscape has led many cities, states, and regions to institute policies aimed at reducing GHG emissions. These policies and emerging initiatives have significant implications for the transportation planning process. About 28% of the United States' GHG emissions are from transportation sources. Carbon dioxide emissions from personal vehicles and trucks account for 82% of these emissions and have grown by 28% since 1990. Unlike conventional air pollutants, carbon dioxide emissions are directly tied to the amount of fuel consumed and its carbon intensity. Therefore, emissions reductions can be achieved by increasing the use of low-carbon fuels, improving fuel economy, or reducing total vehicle miles--often called the three legged stool. (A fourth leg is congestion reduction, at certain optimal speeds). These same factors are related to our use of imported oil, so actions taken to reduce GHG emissions may actually produce benefits in both policy areas.The global scale and indirect nature of climate change make it impossible to quantify the damages associated with any individual sources of new emissions, no matter how large. While highway projects might contribute to increased greenhouse gases, the climate impacts of expanding capacity in a particular corridor cannot be effectively determined. Therefore, the traditional approaches such as impact mitigation become more complicated. On the other hand, states implementing greenhouse gas policies have chosen to focus primarily on quantifying emissions impacts and setting emissions-reduction goals. Emerging policies and performance measures have been expressed as reductions in vehicle miles traveled, regional emissions targets, or incentive-based goals. The climatic risks of additional emissions associated with capacity projects must be balanced against the mobility, safety, and economic needs of a community or region. The difficult questions lie in where and how in the transportation planning process the assessments should occur. Project C09 specifically focuses on the state and local collaborative decision-making framework as the context for this work. It will examine strategies to integrate GHG emissions and energy consumption considerations when transportation policy strategies can address both. This project will NOT focus on transportation and air quality modeling in areas where such modeling is a mature practice. Where such modeling is done, the outputs of travel demand models are inputs to EPA's MOBILE 6 or MOVES models, which estimate emissions, including carbon dioxide. The MOVES model represents a substantial potential improvement over MOBILE 6, but its data needs strain the ability of travel demand models to produce inputs at sufficiently fine detail. The SHRP 2 Capacity Technical Coordinating Committee recognizes that improvements to travel demand models are needed to better address GHGs and has assigned that charge to SHRP 2 Project C10. It should not be emphasized in this project. Rural areas or regions where rigorous air quality analysis is not required are a different question. How should the GHG issue be addressed there?It doesn't matter where GHGs are emitted, the global effect is the same. Some states are requiring that the GHG effects of long-range transportation plans be estimated, even if the region is not required to conduct air quality analysis to satisfy the Clean Air Act. This is a very real problem at the moment and is within the scope of this project.This research will be conducted in an environment of uncertainty.Critical policies are currently in flux: The Environmental Protection Agency has announced a proposed rulemaking process to address the issue; states are adopting policies; local governments are adopting targets and goals; and recent fuel price increases are changing driving behavior, at least in the short term. This project should examine ways to incorporate the GHG emission issue into the collaborative decision-making framework based on the current regulatory environment. If the environment changes during the project, we will have to adapt. If it doesn't, this work will contribute to the policy debate. The objectives of this project are to: (1) Develop a strategy or strategies for addressing greenhouse gas emissions at relevant key decision points in the Collaborative Decision-Making Framework; (2) identify relevant material already produced by the normal planning process and the gaps that exist for GHG analysis, (3) prepare materials and methods to address the gaps and integrate them into the CDMF; (4) prepare a freestanding Practitioner's Handbook.Accomplishing these objectives will require identifying proactive strategies that can be taken by cities, states, and regions to reduce GHG emissions from the transportation sector: Identifying what practitioners need to know about greenhouse gases at each stage of the CDMF; identifying the audiences at those key decision points; and identifying the most critical gaps and needs.


  • English


  • Status: Completed
  • Contract Numbers:

    Project C09

  • Sponsor Organizations:

    Strategic Highway Research Program 2

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC    20001
  • Project Managers:

    Andrle, Stephen

  • Performing Organizations:

    PB Americas, Incorporated

  • Start Date: 20090210
  • Expected Completion Date: 0
  • Actual Completion Date: 20110530
  • Source Data: RiP Project 16656

Subject/Index Terms

Filing Info

  • Accession Number: 01462676
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project C09
  • Files: TRB, RiP
  • Created Date: Jan 3 2013 2:08PM