Freight transport structure evaluation and optimization toward sustainable development: New evidence from the SBM-DEA model with undesirable outputs

Improving transport efficiency and optimizing freight structure are the core of achieving sustainable transport development. However, few studies have conducted an in-depth analysis of freight structure optimization and transport efficiency at the provincial level in China. Hence, a new economy and carbon dioxide (CO₂) emissions evaluation model based on the slack-based measurement data envelopment analysis (SBM-DEA) with undesirable outputs was proposed to analyze the transport efficiency and optimize freight structure in five provinces of China from 2005 to 2019. And optimization potential of the freight and passenger transport sector was uncovered in the provinces. The results showed that: (1) the regional difference in transport efficiency was significant, which indicated room for improvement in these provinces. (2) Freight structure was estimated and optimized by the slack variables of the evaluation model. The slack variables of railway, road, and waterway freight transport were large among these provinces. (3) The optimization potential of the freight transport sector was greater than that of the passenger transport in the regions. It indicated optimizing freight structure should be prioritized over passenger transport. Finally, some implications were put forward for sustainable transport development in China. The results provide significant insight into freight structure optimization as well as novel perspectives into the formulation of carbon mitigation strategies.