1. Lecturer in Transport Studies, Dept. of Civil and Building Engineering, Loughborough Univ., Leicestershire LE11 3TU, U.K. (corresponding author).
2. Research Ph.D. Student, Dept. of Civil and Building Engineering, Loughborough Univ., Leicestershire LE11 3TU, U.K.
3. Professor of Transport Policy, Dept. of Civil and Building Engineering, Loughborough Univ., Leicestershire LE11 3TU, U.K.