Cooperative test programs were conducted during 1984 and 1985 by the Coordinating Research Council (CRC) to investigate the driveability of hydrocarbon-only and hydrocarbon-alcohol blends. The 1984 program was the first CRC intermediate temperature program on fuels containing alcohols. The 1985 program evaluated the performance of hydrocarbon and hydrocarbon-alcohol blends at higher temperatures. Both programs contained three vehicle subsets that were classified by fuel delivery system-carbureted, port fuel-injected, and throttle body fuel-injected vehicles. Both fuel-injected vehicle sets gave significantly lower demerits compared to carbureted vehicle sets. Fuel volatility and alcohol type/content were found to be significant variables for many of the fuel combinations evaluated.