Do urban motor vehicle restriction policies truly control urban air quality?

Abstract

Traffic restrictions have received increasing attention in academia and are becoming a major measure to control urban air pollution. Many studies have evaluated the effects of such restrictions but have yielded mixed results. In this paper, 32 key cities in China are selected for comparative experiments. Cities that implemented traffic restriction policies are used as the experimental group, and other cities that did not implement traffic restrictions are regarded as the control group. First, based on a multi-period difference-in-difference model, we find that the implementation of traffic restriction policies improves urban air pollution. Second, we analyze the effect of only license-plate restrictions on air quality and discover that urban air pollution is still improved. Finally, we reveal that traffic restriction policies achieve different results in northern and southern Chinese cities.