Urban experiments with public transport for low carbon mobility transitions in cities: A systematic literature review (1990–2020)

The development of public transport in cities can facilitate multiple ways under the Avoid-Shift-Improve (ASI) framework in reducing greenhouse gas (GHG) emissions from passenger mobility. Nevertheless, ensuring their integration and direction for moving toward low carbon mobility transitions is often challenging in practice. Urban experimentation has emerged as a governance model to foster innovations for climate change mitigation in cities while articulating a sustainable future. This paper aims to review how urban public transport experiments ensure the selection and consolidation of ASI measures to support low carbon mobility transitions. Our analysis is based on a systematic review of 41 documents gathered from peer-reviewed and grey literature databases. We find that experimentation is a critical platform for introducing novel ASI-public transport measures and exploring potential pathways toward the transitions through participative backcasting approaches. In our database, the experiments generally contribute to the rollout of LEV technologies and BRT systems, followed by the development of other ASI measures. Some of the experiments establish climate change targets to support low carbon mobility. Our review demonstrates that the experiments hold a pivotal role in developing niches for ASI-based measures and stimulating policy processes for the long-term transitions