Analyzing the threshold effect of environmental regulation and logistics industry agglomeration on road green logistics efficiency: A case study in China

Road green logistics play a crucial role in promoting a nation’s sustainable economic growth. Environmental regulation (ER) is considered as a major activity to stimulate the development of green logistics. Meanwhile, logistics industry agglomeration (LIA) could enhance the logistics efficiency with reasonable agglomeration. However, the contradiction between them is also becoming important, and the rapid development of logistics has brought huge pressure on the environment. Therefore, the complicated relationship between ER, LIA and road green logistics efficiency(RGLE) needs to be further clarified. Using panel data between 2008 and 2020 in China's 30 provinces, this study measures the RGLE with Super-SBM model. The complex relationships between ER, LIA, and RGLE are then examined with panel regression models. Empirical results indicate that the average RGLE demonstrates a trend of initially declining and then rising, with notable spatial variations. Interestingly, econometric findings confirm that ER does not directly improve RGLE but effectively enhances it through its moderation with LIA. Furthermore, the impact of ER on RGLE exhibits a "U-shaped" relationship under different agglomeration threshold values in the logistics industry. Consequently, this study suggests optimizing LIA and strengthening regional linkage to improve RGLE.