Fuel economy estimates are provided for the CleanFleet vans operated for two years by FedEx in Southern California. Between one and three vehicle manufacturers (Chevrolet, Dodge, and Ford) supplied vans powered by compressed natural gas (CNG), propane gas, California Phase 2 reformulated gasoline (RFG), methanol (M-85), and unleaded gasoline as a control. Two electric G-Vans, manufactured by Conceptor Corporation, were supplied by Southern California Edison. Vehicle and engine technologies are representative of those available in early 1992. A total of 111 vans were assigned to FedEx delivery routes at five demonstration sites. The driver and route assignments were periodically rotated within each site to ensure that each vehicle would experience a range of driving conditions. Regression analysis was used to estimate the relationships between vehicle fuel economy and factors such as the number of miles driven and the number of delivery stops made each day. The energy adjusted fuel economy (distance per energy consumed) of the alternative fuel vans operating on a typical FedEx duty cycle was between 13% lower and 4% higher than that of control vans from the same manufacturer. These comparisons are affected to varying degrees by differences in engine technology used in the alternative fuel and control vehicles. Relative fuel economy results from dynamometer emissions tests were generally consistent with those obtained from FedEx operations.