On January 21, UCLA Faculty Rui Wang presented his research, Restricting Driving for Better Traffic and Clearer Skies: Did It Work in Beijing?  to a capacity crowd  at the University of Southern California as the first METRANS Transportation Research Seminar presentation of the new year, and a joint effort of METRANS and the USC Sol Global student organization.  Wang examined the impact of Beijing driving restrictions on congestion and air pollution in the city of Beijing and shared his results with an audience of more than 70 students, faculty, and practitioners.   

Wang notes that driving restrictions have been implemented in cities across the world. However, few studies have quantified their impact on traffic, and the conclusions regarding the impact on air quality are mixed. Wang began by sharing the varied results from previous studies. USC Transportation Systems graduate student from Croatia, Hrvoje Rak, who plans to pursue a career as a transportation engineer, noted that Wang “did a very interesting analysis of driving restrictions and their environmental and traffic impacts. The results were surprisingly different among different studies, and the professor presented and described them very well so that we could understand them clearly.”

 In Beijing, driving is restricted based on the last digit of a vehicle’s license plate number, with each terminal digit (0 through 9) restricted the same number of times in a week as any other.  Wang was able to take advantage of the Chinese cultural resentment toward the number “four” and the provision that plate numbers may be selected by the driver to identify the marginal effects of driving restrictions.   Quite simply, since license plates in China are significantly less likely to end with the digit “four,” restrictions based on the number four impact fewer vehicles than those identifying any other digit.  USC Master of Planning student Feiyang Zhang, a Chinese national who plans to work as an urban designer after graduation, found “his use of the ‘death effect’ of the number ‘four’ to be most interesting in carrying out his study.” Wang’s study discovered that driving restrictions had a positive impact on city-wide traffic speed, but little effect on the concentration of inhalable particulates.

USC Master of Planning student Katherine Taveras, a New York City native who hopes to establish a career as a preservation planner, remarked, “I learned that cleaner air policies don’t necessarily result in better traffic and vice versa. What interests me most about transportation is how it affects the way of life. I like the idea of finding practical ways of moving people that are socially and environmentally responsible.”

Wang is an Assistant Professor of Urban Planning at UCLA, specializing in the interdisciplinary policy analysis of environmental, transportation, and urban development issues, particularly in China and the US. He teaches in the Departments of Urban Planning and Public Policy, directs the UCLA Chinese Planning Professional Training Program, and serves on the Editorial Board of the Journal of Transportation and Statistics. Professor Wang has consulted with the Beijing Municipal Institute of City Planning and Design, the U.S. Department of Housing and Urban Development, and the World Bank. He has also given invited talks at the China Finance 40 Forum, the Hong Kong Monetary Authority, RAND, the World Bank, and numerous academic conferences and institutions.

Wang’s full presentation can be viewed on METRANS iTunes U:   https://www.youtube.com/watch?v=HHfv4RpNJIk&feature=youtu.be