Congestion assessment for the Belt and Road countries considering carbon emission reduction

In the context of resources saving and climate change, this study extends the Cooper-family model by using a range adjusted measure (RAM) approach to incorporate carbon emissions under the data envelopment analysis (DEA) framework. Comparing congestion effects under three orientations (operational orientation, environmental orientation, and sustainable orientation) of 46 primary countries along the Belt and Road (B&R countries) from 2003 to 2016, this study has a sight for the impact mechanism of development orientation on congestion effects and put forward policy suggestions on development orientation for B&R countries. The results show that: 1) Congestion effects have existed in some B&R countries during the sample period. Labor congestion mainly occurs under environmental orientation, capital congestion mainly appears when operational performance or sustainable development is the priorities orientation, and energy congestion under operational orientation is more severe than the other orientations. 2) Countries rich in a production factor tend to have congestion of such production factor. Specifically, high population density countries, developed countries, and countries rich in energy resources tend to have labor congestion, capital congestion, and energy congestion, respectively. 3) Sustainable orientation will help to alleviate congestion effects. Serious capital and energy congestion have occurred under operational orientation, whereas they are basically eliminated when under sustainable orientation. The findings are helpful to improve resource utilization efficiency and provide foreign investors with investment reference information.