Over the last ten years, improved vehicle technologies and fuel quality have been seen as primary contributors to better air quality in European cities. The Auto Oil programme involving both government and industry has been central to the process of designing appropriate regulatory policies. However, in its second phase this programme has drawn attention to the potential contribution of non-technical measures (such as traffic management, pricing measures and promotion of public transport). These offer a means of supplementing the gains from vehicle technology, by acting on the total demand for mobility and modal split. They can also influence the adoption of technical measures, e.g. through economic incentives such as scrappage schemes. It is possible that they offer more cost-effective reductions in emissions than do some of the increasingly expensive technological innovations.