1. Professor, School of Highway, Chang’an Univ., Xi’an, Shaanxi 710064, China (corresponding author).
2. Postgraduate, School of Highway, Chang’an Univ., Xi’an, Shaanxi 710064, China.
3. Engineer, Shanxi Transportation Holdings Group Co., South Central St., Xuefu District, Tai yuan, Shanxi 030032, China.
4. Senior Engineer, Shanxi Transportation Holdings Group Co., South Central St., Xuefu District, Tai yuan, Shanxi 030032, China.