This paper describes DELPHI, a pilot version of a joint web decision support application for real time traffic situation and prognosis, information exchange and cooperation between the Traffic Management Center, Emergency Rescue Services, the Police and the Emergency Call Center. In two demonstration regions in Germany, Cologne and Munich the R&D project started in 2007. The main purpose is to handle major incidents that affect the transportation situation in conurbation areas. The web application is intended to help task force members at different stakeholders to obtain a common and joint overview. DELPHI also allows to coordinate tactical measures among the task forces.