Samenvatting
Twenty years of innovation in the public transport in different countries are described. The improvement of public transport led to the construction of new systems and new transport modes. After the energy crisis there was a change in thinking. Starting points were product, market, function, research and development. From 1960 to 1970 automatic system raised from function and research and development. The second innovation wave raised from product. It concerns novelties, product improvement and the bringing together of existing systems.