Affiliation: | aCentre for Transport Research, School of Geosciences, University of Aberdeen, St. Mary’s, Elphinstone Road, Aberdeen AB24 3UF, UK;bT2E Transport to Employment and the Transport Research Institute, Napier University, Edinburgh EH10 5DT, UK;cTransport Operations Research Group, School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK |