Concurrent air quality analysis under the National Environmental Policy Act and transportation air quality conformity

This paper addresses the direct and indirect relationships between the National Environmental Policy Act (NEPA) and the new conformity requirements. This paper concludes that NEPA and transportation/air quality conformity processes should be concurrent. The need for concurrent determinations is supported by five arguments: 1) the legislative history of conformity indicates that project conformity determinations be made during the NEPA process; 2) general NEPA requirements specify coordination between environmental processes; 3) the level of technical detail required for conformity analyses meets or exceeds the level already required for NEPA; 4) unless conformity is taken into account, alternatives and mitigation measures generated during the NEPA analytical process may later result in a negative conformity determination; and 5) public comment periods, unless coordinated, would run consecutively rather than concurrently, potentially delaying project implementation.