In April 2004, EPA designated three areas in South Carolina nonattainment for the 8-hour ozone standard. Two of those areas, Anderson-Greenville-Spartanburg and Columbia, had the effective date of their designation deferred as long as they met milestones agreed to in their 8-hour Ozone Early Action Compact. These areas met all of the milestones and in April 2008, based on ambient air monitoring data for 2005, 2006, and 2007, the areas were redesignated to attainment.

As a result of the deferral, these two areas were not required to implement the Clean Air Act requirement of Transportation Conformity for nonattainment areas. However, air quality and transportation officials agree on the importance of considering air quality goals in transportation planning. The parties involved developed a Smart Highways checklist to be used in transportation planning. This checklist was intended solely as an informational guideline to be used in reviewing Long Range Transportation Plans and Transportation Improvement Programs for adequacy of their documentation and used during long range transportation plan updates as required by 23 CFR 450.322. This process was commonly referred to as Smart Highways. Air quality and transportation officials engaged in the Smart Highways process included the Metropolitan Planning Organizations (MPOs) from the deferred nonattainment EAC areas (ANATS, GPATS, SPATS and COATS), the South Carolina Department of Transportation, Federal Highway Administration South Carolina Division, EPA Region 4, Federal Transit Administration, and the South Carolina Department of Health and Environmental Control.

• Smart Highway Checklist
• Anderson Area Transportation Study
• Columbia Area Transportation Study (COATS)
• Greenville-Pickens Area Transportation Study (GPATS)
• Spartanburg Area Transportation Study (SPATS)