A Pilot Program for Streamlining Carbon Monoxide (CO) Project-Level Air Quality Analyses with Programmatic Agreements (PAs)

Focus Area

Air Quality


Air Quality






Under 1 year

Research Idea Scope

The NCHRP 25-25 Task 78 study (2015) successfully developed templates for programmatic agreement (PA) and associated technical documentation that are designed to be implemented by state DOTs to streamline project-level air quality (hot-spot) analyses for carbon monoxide (CO). The proposed study is for a pilot program that would apply the NCHRP templates for two or three state DOTS, starting from the beginning of the analysis process, making revisions to the templates as needed (e.g., to cover additional project types and/or configurations, and to use state-specific modeling inputs), and continuing through necessary approvals and subsequent execution with FHWA for each state DOT in the pilot program. Lessons learned in this initiative would inform and assist the subsequent implementation of the templates (with any revisions as appropriate) for state DOTs across the nation. For background, project-level CO hot-spot analyses have been undertaken to satisfy environmental requirements for several decades now. Over this period different modeling approaches have been developed and used to determine whether a transportation project has the potential to violate the CO ambient air quality standards. For emissions, the MOBILE series of models have been used until the recent release in 2010 of the first version of MOVES (Motor Vehicle Emissions Simulator). Other models have been developed (such as modal based emissions models) but they were not widely used since the MOBILE series and now MOVES were developed and approved by USEPA. Similarly, dispersion models have undergone changes over this time period. Highway sources have historically been treated as line sources using Gaussian dispersion to deliver CO from the source to the receptor. The HIWAY and CALINE series of models were developed to allow for modeling of roadways. As it was being realized that congested intersections, with most vehicles experiencing idling, acceleration and deceleration associated with a traffic signal, may be more of a concern for CO levels than free-flowing highways, queueing algorithms were added to dispersion models, resulting in the current series of CAL3QHC and CAL3QHC(R) models. Recently, AERMOD has also been recommended for roadway modeling, with guidance provided related to the volume or area source capacities of the model. Over this period of time, many states developed guidance and procedures describing situations or project types that required a hot-spot analysis and prescribed state-specific modeling inputs and other assumptions (e.g. background concentrations) to be used in the analysis. The Tasks for this proposed research would be developed in consultation with the state DOT that would best meet their needs, but in general, would likely consist of Tasks as outlined below: 1. Ascertain from state DOT issues, past procedures, needs, etc. related to CO hot-spot analysis in their state. 2. Obtain and analyze CO monitoring data to develop state-specific background concentrations and persistence factor(s). 3. Perform emissions and dispersion modeling for selected project types and conditions. 4. Apply background concentrations and persistence factors to modeled results to determine which project types and conditions meet CO ambient air quality standards. 5. Using Task 78 templates and results of analyses, complete state-specific PA (and Technical Support Document, as needed) 6. Assist state DOT with PA approvals and implementation, as needed. 7. Develop Final Report documenting issues and obstacles encountered and solutions used to finalize the PA.

Urgency and Payoff

Most recently, NCHRP 25-25 Task 78, developed templates for a PA for CO hot-spot analysis. Since this template was done on a national level, conservative inputs and national default values were used, many of which would likely be less conservative when applied at a state-specific level. The proposed research relies on the experience gained over thirty years doing CO hot-spot analysis for transportation projects. It would most directly build upon the work of NCHRP 25-25, Task 78. The proposed research would use the templates for a CO hot-spot analysis PA developed for that Task and apply it to 2-3 state DOTS. It would start at the beginning of the process and continue through necessary approvals and subsequent PA implementation at the state DOT. With state-specific assumptions and inputs (such as background, persistence factor, fleet mix, fuel mix, I/M program, etc.), more project types (perhaps, park and ride lots, skewed intersections, roundabouts, etc.) and /or more project conditions (such as road grade or number of lanes) could be shown to meet the CO NAAQS in each state. NCHRP 25-25 Task 78 modeled 4 project types: freeways, arterials, intersections and interchanges. Information from this research could then be used to shorten and simplify the process for PA development and implementation for other state DOTs. This would benefit other state DOTs that wish to develop a CO hot-spot PA for their state by avoiding or working around procedural, administrative or technical issues that were encountered and solved during this proposed research. Research is needed to identify and address issues with development and implementation of PAs to be used by state DOTs to determine and document under what project types and conditions (e.g. road grade, number of lanes) a project-level CO hot-spot analysis would not be needed. It is expected that a number of project types and conditions would be modeled and analyzed with state-specific inputs and data. The research would encompass the entire process of PA development and implementation, from start through needed approvals and implementation. Lessons learned from this research could then be used to inform the process for PA development and implementation for other state DOTs. Upon successful completion of the proposed research, similar work could be performed for any state DOT that would benefit from having a state-specific PA in place for CO hot-spot analysis. It is envisioned that most state DOTs would gain a benefit by updating any CO analysis procedures they may have in place.

Suggested By

John Zamurs ZAMURS AND ASSOCIATES, LLC 5184563545

[email protected]