Road transportation green productivity and its threshold effects from environmental regulation

This paper uses the global Malmquist-Luenberger index to investigate changes in road transportation green productivity from 2010 to 2017, incorporating undesirable outputs into the analytical framework. Furthermore, the relationship between environmental regulation and green productivity is tested by the panel threshold model. At the area level, the improvement of green productivity in western China benefits from a catch-up effect and improved scale efficiency. Moreover, the driving factor improving green productivity in China's central and eastern areas is mainly the scale economy, and technology regress is the hindering factor. Research and development investment and government fiscal expenditure both show a single-threshold effect on green productivity. That is, their values in relation to thresholds cause differences in the impact of environmental regulation on green productivity. Our analysis shows that economic development can significantly promote green productivity, while highway density can significantly hinder it. Based on the evidence presented, we put forward practical suggestions for improving green productivity.