The effects of the current fuel economy on public transportation has become of increasing concern. Looking over the facts and projections, it becomes clear that in order to improve the automotive fuel efficiency, industry needs to examine power train components and their effect on obtaining vehicle performance and efficiencies. A joint government-industry program was initiated to investigate the two-shaft gas turbine concept as an alternative to present-day automotive powerplants. Both were examined, compared and evaluated on the basis of the federal automotive driving cycle in terms of specific fuel/power/speed characteristics of the engine and the efficiency and performance of the transmission. The results showed an optimum match of vehicle, gas turbine engine and conventional automatic transmission is capable of a significant improvement in fuel economy. This system offers many advantages that should lead to its wide acceptance in future vehicles.