LAUSR

Abstract Rapid highway expansion in China has contributed positively to economic development; however, it also created environmental pollution problems. This study used direct and indirect perspectives to analyze the impact that highway expansion had on haze pollution and the mechanisms involved. To consider the spatial spillover effect of haze pollution, panel data for 283 cities in China from 2003 to 2016 served as a research sample for regression analysis, based on the spatial Durbin model. Empirical results revealed three key results: 1) The overall relationship between highway expansion and haze pollution in local cities and neighboring cities formed an inverted U-shape: as highway density increased, haze pollution first increased and then decreased; 2) The results of the mediation effect assessment identified three mechanisms by which highway expansion affected haze pollution: the transport effect, the industrial structure effect, and the market segmentation effect; and 3) Heterogeneity analysis revealed that highway expansion decreased haze pollution in central and western cities, inland cities, and in non-resource cities. The conclusions of the work were supported by conducting a robustness test of the regression results, using the generalized space two-stage least square (GS2SLS) method and other methods. Given the possible continued expansion of China's highways, this research has a guiding significance for changing the highway expansion model.