Green efficiency changes of comprehensive transportation in China: Technological change or technical efficiency change?

Based on the concept of green development, we creatively introduce the social development index into the comprehensive transportation efficiency evaluation framework, and try to define the concept of comprehensive transportation green efficiency. We employ the SBM-Malmquist model to measure the comprehensive transportation economic efficiency (CTECE), comprehensive transportation environmental efficiency (CTENE), and comprehensive transportation green efficiency (CTGE), and discusses the reasons and driving factors of efficiency losses. Data sets from 30 provinces in China, from 2003 to 2018, are analyzed. Our results show that SDI (Social Development Index) can significantly promote the comprehensive transportation efficiency. However, the CTGE level in China is relatively low, and the spatial difference are quite large. We also show that both technological change and technological efficiency change can promote CTGE improvement. but the dominant factors have spatial differences. The eastern and central regions primarily benefit from the improvements in technological change and management level, while the western regions mainly rely on expanding production scale to improve CTGE. Our findings provide useful guidelines to transportation around the world, in the process of integrating and consolidating road, railway, water transportation and aviation sectors.