Armin Seyfried Forschungszentrum Jülich This talk gives an overview of the state of the art knowledge about the fundamental diagram of pedestrian streams. Empirical measurements show a high complexity due to several phases: free flow phase, congested phase and a coexistence of stop and go phases. Between these phases non-trivial transitions occur and the structure of the phases is influenced by the measurement method. Moreover experiments display a manifold of influences like culture, motivation or group formations. By comparing fundamental diagrams of cars, bicycles and pedestrians we show the universal character of these relation which is independent from the diversities and manifold of influences outlined above.