School runs and urban traffic congestion: Evidence from China

It is widely believed that school runs generate urban traffic congestion. In this paper, we present credible evidence for this causal link using unique panel data that monitor traffic conditions in Beijing from 2015 to 2016. We adopt a triple difference strategy that utilizes three variations in traffic flows on the roads by school days and school holidays, by roads near and further away from schools, and by hours of school runs and other hours. We find that school runs increase the probability of road congestion by 4.5 percentage points. The impact is larger in the morning than that in the afternoon. Moreover, traffic congestion is more severe around schools that are larger, better, public rather than private, in more expensive neighborhoods, or with no student accommodation. Further analyses reveal that staggered school hours and provision of school buses can reduce congestion and improve social welfare.