The analysis presented in this paper is based on the database created by the UITP (International Association of Public Transport), "The Millennium Cities Database", which covers the public transport systems in 100 of the world's cities. It contains data on demography, urban structure, transport networks, daily mobility, environmental impacts, etc. Our analysis demonstrates the contrasts between European and American travel practices. It explores possible links between public transport market share and geographical and economic conditions on the one hand and the characteristics and performances of public transport systems on the other. Our research has generated an explanatory econometric model for public transport market share. To end with, a consideration of the levers that can be used to influence the public transport system leads into a discussion about the future of cities with ''European urban mobility'' and the danger of a slide towards ''American urban mobility'' taking place.