E20 fuel research conducted by the Rochester Institute of Technology has focused on vehicle exhaust, vehicle drivability and vehicle maintenance. Beginning in February 2008, ten older gasoline vehicles owned and operated by Monroe County, New York State, were evaluated using E20 fuel. Criteria pollutant tailpipe emissions from running E20 versus gasoline were tested using the FTP-75 Federal Test Procedure in an independent vehicle emissions laboratory. Initial results demonstrated significant fleet tailpipe emissions reductions in carbon monoxide and total hydrocarbons when running E20 versus gasoline. The fleet has currently operated a total of more than 100 000 miles on E20, with individual vehicles having been driven at least 2400 miles each on E20 at the time of testing. Driveability and maintenance have been unaffected. Driver comments were strongly positive. Research continues, with future work to include repeat tailpipe emissions testing for degradation and expanding E20 fuel usage to the entire Monroe County vehicle fleet. This paper presents the initial results for the vehicle tailpipe emissions testing on gasoline versus E20. Federal FTP-75 emissions testing was conducted on each vehicle operating on regular unleaded gasoline to obtain baseline data and then on E20. The fleet average experienced a 23.2 per cent decrease in CO emissions on E20. Nine out often test vehicles experienced a reduction in CO, and all vehicles fell well within the EPA full useful life standards for the individual vehicle requirements. The average weighted fleet tailpipe NOX decreased by 2.4 per cent with five vehicles increasing NOX and five decreasing NOX. Two vehicles had increases over 25 per cent; however, all vehicles were well below the EPA requirement for that vehicle. The fleet showed a significant reduction in THC. Nine out of ten vehicles had a reduction in THC, with a fleet average reduction of 13.7 per cent. Fleet average CO2 emissions were reduced by 3.6 per cent, with seven out of ten vehicles showing a reduction.