Evaluating green productivity of the regional transport sector in South Asia considering environmental and safety constraints: the evolution from static and dynamic perspectives

The assessment of green productivity not only establishes the production ability but also involves economic, environmental, and social aspects which are the ultimate goals in achieving the sustainability. In this context, unlike the majority of previous literature, we have simultaneously considered the environmental and safety aspects to measure the static and dynamic evolution of green productivity to achieve a safe, eco-friendly, and sustainable development of the regional transport sector in South Asia. First, we proposed the super-efficiency ray-slack–based measure model with undesirable output to assess the static efficiency, which can effectively characterize weak and strong disposability relationship between desirable and undesirable outputs. Second, the biennial Malmquist-Luenberger index has been adopted to examine the dynamic efficiency, which can overcome recalculation issue once an additional time period is included in the data. Therefore, the proposed methodology provides more comprehensive, robust, and reliable insight in comparison to the conventional models. The results indicate (i) both static and dynamic efficiencies decreased during 2000–2019, implying that the transport sector in South Asia follows an unsustainable green development path at the regional level; (ii) dynamic efficiency was primarily held back by green technological innovation whereas green technical efficiency had a modest positive contribution. The policy implications suggest effective ways to improve green productivity of the transport sector in South Asia by promoting coordinated development among the transport structure, environmental and safety aspects, strengthening advance and innovative production technologies, endorsing green transportation practices, and implementing safety regulations and emission standards for the sustainable transport sector.