Abstract 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 100000 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.