Research Idea Details

Research Idea Scope

A major update to the MOVES emission model used in air quality analyses of transportation improvement projects is expected later this year, which may result in significant changes to forecast emission rates depending on the pollutant. State DOTs would benefit from:

1. Implementation testing to check its performance and identify any issues for project-level modeling, including checking whether issues previously identified have been resolved. For example, the EPA MOVES Review Workgroup* identified a number of issues with the existing model in project-level applications, including anomalous model behavior in sensitivity testing for higher road grades (resulting in either potential overestimation or underestimation of emission factors for particulate matter and carbon monoxide) and the need for mileage-accumulation-rate (MAR) weighting as previously recommended in two NCHRP studies (25-38 and 08-101) that could benefit state DOTs with potentially significantly reduced fleet-average emission factors.

2. Development and recommendation of tools, templates and procedures to streamline and facilitate analyses to the extent feasible, including for example a tool for MAR-weighting in post-processing (if not made part of the model update); examples of modeling input, output and post-processing files for different pollutant analyses for conformity and NEPA; and guidance or examples for developing pre-vetted modeling input data.

3. Development of case studies for emission modeling of typical transportation projects types for both conformity and NEPA, using the tools, templates and streamlined procedures recommended above. The case studies would support training in project-level analyses, which was identified as a need in the 2020 survey of AASHTO Air Quality, Climate Change and Energy Subcommittee members, in addition to facilitating and streamlining analyses and improving quality assurance and control.

* https://www.epa.gov/sites/production/files/2019-12/documents/03-moves-project-level-analyses-2019-10-09.pdf

Urgency and Payoff

Typically, a grace period of up to two years is provided for major MOVES updates. Its implementation within this time-frame by State DOTs would be facilitated by this study through the development of detailed case studies, tools that serve to streamline and improve quality control for analyses, and sensitivity testing.