**5. Conclusions**


**Author Contributions:** Conceptualization, K.L. and S.L.; methodology, K.L.; software, S.L.; validation, S.L., J.C. and X.L.; formal analysis, K.L.; investigation, S.L.; resources, J.C.; data curation, S.L.; writing—original draft preparation, S.L.; writing—review and editing, K.L.; visualization, S.L.; supervision, X.L.; project administration, K.L.; funding acquisition, K.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** The research is supported by Zhejiang Transportation Science and Technology Project No. 2018035.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
