Previous planning studies by the Atlanta Regional Commission (ARC) considered whether the SR 400 Express Lanes project would affect regional air quality. The project was evaluated in the Region’s Air Quality Conformity Analysis and was included in the financially-constrained six-year Transportation Improvement Program (TIP) for the region as early as 2014. The latest Air Quality Conformity Determination Report can be found at this link:. The proposed express lanes project is found in an amendment to the conformity report. All amendments require a conformity determination from the U.S. Department of Transportation, in consultation with the U.S. Environmental Protection Agency (EPA). This amendment will involve a new air quality conformity determination by the United States Department of Transportation and is expected in June 2019. The most recent regional emissions analysis was approved by Federal Highway Administration (FHWA) and EPA on December 4, 2018. Additional background is found at this website:
An air quality analysis will be completed for this project as a part of the environmental process. Intersection analyses to evaluate the project’s potential effects on carbon monoxide emissions will be completed for intersections that exceed the threshold for traffic volumes and traffic delays.