Excise and other duties measures in Europe, threaten to affect the low price of LPG as a car fuel. As a result, this less polluting fuel would lose position. For this reason the Netherlands LPG industry commissioned TNO to undertake a study which would clearly demonstrate the advantages of LPG. The project was carried out in close cooperation with the car manufacturer Fiat. Fiat's involvement has to be related to a wider program focused on the evaluation of the ecological properties of alternative fuels. To ensure that the results would be widely applicable, the study focused on a modern family car with normal compression ratio (Fiat Tempra 2.0 i.e.). A dual fuel system which can smoothly switch between petrol and LPG was used. One of the constraints imposed by the project was that only minor engine modifications would be permitted, allowing application to various engines. This paper reviews the initial stages of the study concentrated on obtaining the best possible engine tuning in terms of efficiency and emissions. At the end of the development program a comparision of exhaust emissions (regulated and non-regulated components) for both petrol and LPG was made. The results of the project showed that LPG does indeed have significant advantages over petrol when considering both regulated and non-regulated components. As the results were based purely on engine tuning, the concept developed here can easily be transferred to other types of cars.