Recent experiences and divergent pathways to transport decoupling

Abstract

This study examines the transport decoupling pathways of the 16 selected countries from 1990 to 2015. Transport carbon emissions (i.e. decarbonisation) and road traffic fatalities (i.e. defatalisation) have been chosen as proxies of environmental and social decoupling respectively. Real GNI in purchasing power parity (based to 2011) is used to reflect the decoupling experience. To frame the transport decoupling pathways, we have applied three decision rules and assigned rankings to the eight decoupling categories identified for richer and poorer countries. Each country has five data points for the ranking (five time periods in the 25-year horizon), meaning that a total of 80 data points have been identified and mapped. Four types of decoupling pathways are derived: Improving, Stable 1, Stable 2 and Unstable. Decoupling policies have then been extracted and analysed to identify the different approaches used in each pathway type. The results show that (i) there is no single pathway to transport decoupling, meaning that a wide range of policies have been adopted by individual countries, (ii) most pathways belong to the ‘Stable’ categories with mild fluctuations in the ranks over time and (iii) defatalisation is more successful than decarbonisation in achieving absolute decoupling. The value of this paper is in its novel methodology that has been used to identify the different pathways for decoupling, its application to 16 key countries, and the use of a database that extends over 5 time periods. It makes a clear contribution to our understanding of the complexity of decoupling, the different pathways adopted, and the difficulties of achieving substantial reductions in transport carbon emissions and traffic fatalities.