Summary

Pursuant to a legislative requirement, GAO reviewed the Environmental Protection Agency's (EPA) new rule on reducing emissions from model year 2004 and later heavy duty highway vehicles. GAO noted that: (1) the rule reaffirms the technical and economic feasibility of the non-methane hydrocarbon plus nitrogen oxide standard promulgated in October 1997; (2) the final rule places new emission standards and related provisions for heavy-duty Otto-cycle engines and vehicles beginning in the 2005 model year or sooner under two optional programs; and (3) EPA complied with the applicable requirements in promulgating the rule.