Layout Methods of Monitoring Stations for Diesel Freight Trucks Emission Supervision Using Highway Traffic Survey Data—— Taking Shanxi Province as an ExampleRui Wu, Honglei Xu, Jie Liu, Xiaowen Yang, Xiaoyu Tan, Weiwei Gong and Jing LinE3S Web Conf., 145 (2020) 02026DOI: https://doi.org/10.1051/e3sconf/202014502026