1. Lecturer, Dept. of Urban and Rural Planning, College of Urban and Environmental Sciences, Northwest Univ., Xi’an, Shaanxi 710127, P.R. China.
2. Professor, Dept. of Traffic Engineering, School of Highway, Chang’an Univ., P.O. Box 487, Middle Section of South 2nd Ring Rd., Xi’an, Shaanxi 710064, P.R. China (corresponding author).
3. Associate Professor, Dept. of Traffic Engineering, School of Highway, Chang’an Univ., Xi’an, Shaanxi 710064, P.R. China.
4. Professor, Faculty of Architecture, Building and Planning, Univ. of Melbourne, Parkville, VIC 3010, Australia