Titolo della tesi: The ecological r-evolution of public transport: a strategic and economic analysis with policy recommendations
The world urgently needs to significantly reduce harmful emissions produced by the transportation sector. Decarbonization and digitalization of passenger mobility are two major challenges currently faced by transport planners worldwide. To this end, public transport plays a pivotal role in reducing pollution and congestion levels within cities, relating to ecological transition in two ways: as an important part of the solution and, at the same time, as a mobility provider that deals with the adoption of some disruptive innovations (i.e., electric vehicles, digital platforms, and automated driving).
This thesis explores challenges and opportunities related to alternatively powered buses (e.g., electric buses, fuel cell buses, and renewable fuels) from a policy making perspective. We particularly focus on zero-emission buses (ZEBs), mostly electric battery buses (BEBs), since they nullify harmful emissions produced at the tailpipe. Due to some advantageous features of public transport provision compared to private mobility (e.g., fixed schedules and centralized depots), electric buses are considered the bridgehead to accelerate clean vehicle adoption in road transport. Indeed, public policies aimed at accelerating the large-scale deployment of ZEBs are boosting across the world. In this context, assuming public spending limits, we aim to answer the question of whether and how governments should support electric buses in order to speed up the ecological transition of urban mobility.
We address this issue by combining two approaches: firstly, we conduct a literature review of decision-making factors that affect ZEBs adoption, which allows drawing some strategic evaluations related to public transport electrification; secondly, we develop an economic analysis of alternative bus technologies and their impact on social welfare.
The economic analysis shows that there is a significant difference in the social cost-effectiveness of alternative power technologies according to various operational and geographical contexts. Providing public subsidies only for ZEBs may be justified in densely populated metropolitan areas from a social cost perspective, while the breakeven point is still far in smaller urban centres and suburban areas. This is even more evident when we consider the marginal external costs of other travel modes (especially private cars), moving from social cost analysis to urban welfare optimization. The most striking result is that introducing electric buses is not welfare improving even in a congested inner city corridor. In both cases, the main reason is that higher supply costs are not offset by the gain obtained in terms of reduced external costs. BEBs significantly reduce harmful emissions of transit services but, in magnitude, the monetary value of such damage really represents a very small component of the welfare. The social benefit of reducing the modal share of car trips is much higher than that of simply cutting marginal external damage of bus services. Therefore, other policy instruments such as optimizing bus fares and frequencies and road pricing can be more effective in improving urban welfare and reducing harmful emissions. However, when we broaden our perspective and discuss strategic evaluations, some positive side effects play in favour of electric buses. Large-scale deployment of BEBs facilitates the overall electrification of the transport sector, coordinating involved multi-actors and reducing the risk of futile investments related to the chicken-and-egg problem of electric mobility. The high visibility of electric city buses can contribute to calling attention to the urgent issue of the environment and climate change. Given the growing importance of the environmental factor in consumers’ preferences, electric buses can be seen as a lever to increase the modal share of public transport.
Regarding how to accelerate the ecological transition of public transport, the first evidence is that BEBs require a different approach in the transit service organization. The need for new supporting infrastructures implies defining integrated urban plans involving transport and energy sectors. It is not a question of replacing a bus with another; it requires switching from a vehicle perspective to transport system design, which is also important in defining public funding schemes. To this end, policy makers should keep in mind some important caveats. Introducing electric buses significantly reduces bus operator surplus, and then an increase in public subsidies is vital for non-profitable transit routes. There is a clear need for innovative regulation models that involve all the stakeholders of the production chain, promote collaboration among them, and ensure better distribution of risks. Public authorities should ensure the real benefits of transit electrification in terms of environmental impact, adopting a comprehensive life cycle perspective with respect to different energy sources, vehicle components, and supporting infrastructures. Finally, policy makers must not underestimate the importance of increasing public transport demand and thus its level of revenue, which can represent the first financing source for bus operators and a key enabler for investing in new technologies.
This is a crucial challenge for transport planning, which is intrinsically conceived as supply-centric, and urgently needs a paradigm shift towards a demand-centric vision.