1. Department of Transport and Planning, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, P.O. Box 5048, 2600 GA Delft, Netherlands.
2. MARCEL, Pendrechtseweg 12, 3084 NL Rotterdam, Netherlands.
3. KiM Netherlands Institute for Transport Policy Analysis, Ministry of Transport, Public Works and Water Management, Plesmanweg 1–6, P.O. Box 20901, 2500 EX The Hague, Netherlands.