In 1977 Hillsborough County was determined to be exceeding the federal ozone standard and was classified as “nonattainment”.  Upon the enactment of the Clean Air Act Amendments of 1990, Congress established a link between transportation funding and an area’s ozone status.  In response to this federal action the State Department of Environmental Protection, in coordination with state and local transportation and air quality agencies, devised a plan to reduce the transportation impact on the state’s air quality.  Initial provisions of this plan subjected residents of Hillsborough County to mandatory vehicle emissions testing, and the federal government required Metropolitan Planning Organizations (MPO) to consider the air quality impacts of their transportation plans. 

In May 2004 EPA declared the entire State of Florida to be attaining the federal ozone standard.  This marked the end of transportation planning mandates.  Air quality is no longer a primary consideration in the development of transportation plans.  However, the possibility of returning to ozone nonattainment still remains.  The burden of reducing public exposure to transportation-related air pollution rests in voluntary emissions control programs.  The benefits of this multifaceted approach will result in reduced travel time, proper vehicle maintenance and optimal air quality.