Cleaner vehicles and alternative fuels can help to achieve Europe's goals for air quality, carbon savings and security of energy supply. However, there are many barriers to the introduction of these new technologies, such as high capital and lifetime costs and a lack of refuelling infrastructure. Certain niche applications such as public sector fleets can provide a way of lowering some of the barriers, and demonstration projects are important in developing market acceptance. City authorities, national governments and the European Community have a vital role to play, both in funding projects and in establishing a strong framework of supporting policies.