Urban traffic infrastructure investment and air pollution: Evidence from the 83 cities in China

Emissions from heavy urban traffic have been the most abundant components of urban air pollution in China. Compared to the fast increasing consumption of automobile, the growth rate of urban traffic infrastructure investment (UTII) is relative low. It is a controversial issue for the policymaker whether promoting the UTII could make a positive impact on reducing air pollution or not. This study is designed to test the relations between the UTII and air quality, using the data of 83 cities from 2000 to 2012. Based on the empirical results from the fixed effect model and dynamic panel data model, increasing the UTII could generally mitigate the air pollution, but the long-run and short-run effects are significantly different. In the short run, the UTII effect on air quality is −0.02, since the urban traffic infrastructure construction might cause more detours and road blockages, which would enhance the fine-particle emissions of the low-speed traffic. In contrast, the UTII could widen the roads and make the traffic system more accessible in the long run, so the estimated positive effect is about 0.05. The robustness tests about different regions and scales of cities are conducted. Policy suggestions are further recommended to reduce air pollution.