A bill to amend the Clean Air Act to require the Administrator of the Environmental Protection Agency to determine the effectiveness of State vehicle emission control inspection and maintenance programs before implementing the additional State plan requirements under the Clean Air Act applicable to such programs.

Amends the Clean Air Act to direct the Administrator of the Environmental Protection Agency to evaluate existing State vehicle emission control inspection and maintenance programs for cost-effectiveness. Prohibits the implementation of additional requirements in a State unless the Administrator determines such additional requirements to be the most cost-effective in attaining the national ambient air quality standards for such State.