1. Institute for Traffic Engineering and Management, Ruhr University Bochum, Universitaetsstr. 150, D-44801 Bochum, Germany.
2. Institute for Transport Studies, Karlsruhe Institute of Technology, Kaiserstrasse 12, D-76131 Karlsruhe, Germany.
3. Trier University of Applied Sciences, Schneidershof, D-54293 Trier, Germany.
4. Traffic Engineering and Control, Technische Universität München, Arcisstr. 21, D-80333 Munich, Germany.