In this action we are adopting revised exhaust emission standards for currently regulated highway motorcycles. We are also adopting new exhaust emissions standards for motorcycles of less than 50 cubic centimeters in displacement, which had not previously been subject to EPA regulations. Finally, we are adopting new permeation evaporative emission standards for all classes of highway motorcycles. Highway motorcycles contribute to ozone and particulate matter (PM) nonattainment, as well as other types of pollution impacting human health and welfare. We expect that manufacturers will be able to maintain or even improve the performance of their products without compromising safety when producing highway motorcycles in compliance with these standards. In fact, we estimate that the fuel costs savings associated with these regulations will offset about one fourth of the program's cost by the time the standards are fully phased in (2030). There are also several provisions to address the unique limitations of small volume manufacturers.