The U.S. Department of Energy and the U.S. Environmental Protection Agency have established, through a Memorandum of Understanding, a coordinated framework for collaborative research examining the impact of alternative motor vehicle fuels on air quality and risk to public health and welfare. A cooperative effort to examine the emissions and fuel economy of DOE flex-fuel vehicles, capable of operating on a variety of liquid fuels, and the atmospheric chemistry of the emissions, will begin in January, 1992. During the first year, emissions will be characterized for 6 vehicles, 2 conventional fuel baseline vehicles and 4 flex-fuel vehicles, using up to 9 fuels. Additionally, a dual-chamber irradiation facility will be constructed to support future study of the atmospheric chemistry of the emissions. These studies will examine the formation of ozone and toxic compounds. A detailed description of the experimental procedures to be used is provided.