Environmental efficiency of land transportation in China: A parallel slack-based measure for regional and temporal analysis

As the second largest economic entity in the world, China plays an important role in controlling global carbon dioxide (CO2) emissions. The land transportation sector (including railway transportation and road transportation) has been the most important source of emissions in China and the average CO2 emissions of land transportation were 529.31 million tons during the period 2009-2012. In this study, a parallel Slack-Based Measure Data Envelopment Analysis model is proposed, which is used for evaluating the overall efficiency of the land transportation sector and individual efficiencies of the railway transportation and highway transportation subsectors at the same time, considering CO2 emissions. The empirical results lead to three conclusions: (a) only Anhui province is efficient each year during 2009-2012. (b) The environmental efficiency of the Eastern area in China is the best, followed by the Central area, with the Western area being the worst. (c) The performance of railway transportation is better than that of highway transportation. These three conclusions lead to policy suggestions to promote highway transportation technological innovation and narrow the regional imbalances in land transportation. This paper makes two main contributions: the model advances improvements to methods used in the Data Envelopment Analysis technique, and also provides governments with a practical and yet easy-to-adopt perspective to implement land transportation performance measurement that aids in decision making.