1. School of City and Regional Planning, Cardiff University, Glamorgan Building, King Edward VII Avenue, Cardiff CF10 3WA, Wales
2. Institute of Transport and Rural Research, School of Geosciences, University of Aberdeen, Elphinstone Road, Aberdeen AB24 3UF, Scotland
3. Centre for Sustainable Transport and School of Geography, University of Plymouth, Drake Circus, Plymouth PL4 8AA, England
4. Department of Development and Planning, Aalborg University, Fibigerstraede 13.50, 9220 Aalborg East, Denmark