1. Professor, Director, Highway School, Chang’an Univ., Middle of South 2nd-ring Rd., Xi’an 710064, China.
2. Ph.D. Candidate, Highway School, Chang’an Univ., Middle of South 2nd-ring Rd., Xi’an 710064, China; and Visiting Scholar, Univ. of Texas, Austin, TX 78712 (corresponding author).
3. Ph.D. Candidate, Senior Engineer, Key Laboratory of Rd. Engineering for Cold Region, First Highway Survey and Design Institute of China, Hi-Tech Industry Development Zone, Xi’an 710075, China.
4. Associate Professor, Associate Director, Highway School, Chang’an Univ., Middle of South 2nd-ring Rd., Xi’an 710064, China.