The selection of fuels for use in transportation has been based upon cost, function, available energy resources and convenience. Petroleum-derived fuels, gasoline and diesel, have consistently been the fuels of choice. Concern for the effects of selected species in the products of combustion of hydrocarbons on the environment continues to increase, and will influence choice of fuels in the future. Fuel properties vary widely among the alternatives worthy of consideration for the future. Utilization of alternative fuels will require innovative approaches in sensors and controls in order to develop vehicles with features and function to rival current vehicles. The fuel composition sensor, on-board computer and related controls used on Flexible Fuel Vehicles have resolved the transition issue to methanol fuel. Sensors and control systems remain to be developed for other fuel alternatives.