Prediction of traffic (like weather forecast), its planning and control are counted among the great scientific and technological challenges. Similarly, flow of granular material like tablets or powders is of immense importance for industrial processing of solids. Both fields have intriguing conceptual analogies.From 9-11 October, 1995, the German Supercomputing Center HLRZ (Höchstleitungsrechenzentrum) at the research center Jülich (KFA) organized an international workshop 'Traffic and Granular Flow'. The purpose of this workshop was to promote the interaction between these two scientific fields, to which supercomputing is making essential contributions, and to stimulate the transfer between basic and applied research.