A test program was undertaken to demonstrate that a realistic gasoline could reduce both hydrocarbon mass and reactivity of vehicle exhaust emissions and simultaneously reduce toxics, carbon monoxide, and nitrogen oxide emissions. In order to evaluate the effect of RVP and aromatics, four highly reformulated gasolines were blended from existing refinery streams with RVP at a nominal 8 and 7 psi and aromatics at a nominal20 and 10 vol%. The emissions performance of these fuels were measured in a fleet of ten 1990 California vehicles.When compared to industry average gasoline, each of the four gasoline test blends demonstrated substantial emission reductions in criteria pollutants and toxics. Estimates of the cost and emission benefit of these gasolines were used to evaluate the cost-effectiveness of these formulations for California. For example, the test blend which was determined to be the most cost-effective exhibited the following exhaust emission reductions: THC 30%, CO 26%, NOx 25%, and toxics 41%.