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Research Idea Details




Assessment of How State DOTs set CMAQ Emission Reduction Performance Measures Targets

Focus Area

Air Quality






1-2 years

Research Idea Scope

Background On January 18, 2017, the Federal Highway Administration (FHWA) published the final performance measure rule (PM3) under MAP-21. This rule, which took effect on May 20, 2017, established CMAQ Emission Reduction performance measures for State DOTs and metropolitan planning organizations (MPOs). Under this rule, state DOTs and MPOs that include nonattainment or maintenance areas for ozone, carbon monoxide, or particulate matter in their jurisdiction are required to establish emission reduction targets. The baseline performance period report was due to FHWA by October 1, 2018 and included CMAQ emissions reductions from the previous four years and targets for the upcoming four-year performance period. Establishing baseline emission reductions is straight forward as it was based on what was submitted to the CMAQ Public Access System. Methods for developing targets for the upcoming performance period, however, are more complicated and anecdotal evidence indicates that methods varied from state to state. Challenges in setting emission targets include accounting for declining vehicle emission rates as a result of increasing more stringent vehicle emission and fuel quality standards.. Many state DOTs and MPOs may not have a statewide approach for calculating emission rates, which creates variability in similar project types that are submitted to the CMAQ Public access system for the same state. Additionally, some projects provide large emission reductions, like diesel retrofits and paving previously unpaved roads, while other projects have multiple co-benefits but can have lower emission reductions. For example, bicycle and pedestrian paths offer health benefits beyond those from the emission reductions. A new consideration is that state DOTs and MPOs that want to streamline the modeling process and save time and cost may wish to apply the new Simplified CMAQ Toolkit (from NCHRP 25-25: Task 108 “Creating Look-Up Tables to Streamline the Determination of Emission Reductions for CMAQ projects”) and/or the FHWA CMAQ Toolkit for this purpose, requiring updates to the performance targets. Lastly, the process to allocate CMAQ funds varies from state to state; in some states the funds are fully allocated by MPOs, in others, the state plays a greater role. Research Problem Statement This research will synthesize how state DOTs established their initial CMAQ Emission Reduction Targets and develop approaches for State DOTs to estimate future targets to identify appropriate targets for the next performance period. This information would also support optional target revisions during the mid-performance period report process. Tasks include: 1. Identify baseline emissions and emission targets that were submitted to FHWA by pollutant of concern. 2. Identify methods state DOTs used to establish emission reduction targets by performing surveys, including the following considerations: a. Were emission reduction targets similar to baseline emissions? Why or why not? b. Which emission targets were significantly lower than baseline emissions? What reasons did the state DOT provide? c. Did states select emission targets above their baseline emissions? Why? 3. Identify best practices for establishing appropriate emission reduction targets for state DOTs and MPOs. 4. For 5 pilot states, provide additional data assessment to improve their ability to set appropriate targets based on their state CMAQ funds distribution processes. For each pilot use the CMAQ Simplified Toolkit from NCHRP 25-25: Task 108 “Creating Look-Up Tables to Streamline the Determination of Emission Reductions for CMAQ projects” and/or the FHWA CMAQ Toolkit to develop potential emission targets. 5. Develop recommendations for how to update performance targets particularly for those using the CMAQ Simplified Toolkit and/or the FHWA CMAQ Toolkit.

Urgency and Payoff

If a state does not meet their established CMAQ emission targets during the performance period, the state DOT must address the reasons why and actions that will be taken to do so in a report to FHWA. This work is urgent because states will soon begin working on their mid-performance period reports. At this point, states have the option to modify their target if necessary. This work will also support state DOT and MPO efforts to establish future CMAQ emission targets, as required by FHWA.

Suggested By

Karin Landsberg Senior Policy Specialist - Air Quality and Climate Washington State Department of Transportation 360-705-7491

Posting Date

June 3, 2019

New - items posted in the last 7 days (30 days for TERI)

AASHTO (American Association of State Highway and Transportation Officials)
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