1. Assistant Professor, Dept. of Civil and Environment Engineering, The Hong Kong Polytechnic Univ., Hong Kong.
2. Assistant Professor, Dept. of Civil and Environment Engineering, The Hong Kong Polytechnic Univ., Hung Hom, Kowloon, Hong Kong (corresponding author).
3. Research and Development, Highways Dept., Hong Kong SAR, Ho Man Tin, Kowloon, Hong Kong.