  Increasing urbanization and exacerbation of sustainability goals threaten the
operational efficiency of current transportation systems and confront cities
with complex choices with huge impact on future generations. At the same time,
the rise of private, profit-maximizing Mobility Service Providers leveraging
public resources, such as ride-hailing companies, entangles current regulation
schemes. This calls for tools to study such complex socio-technical problems.
In this paper, we provide a game-theoretic framework to study interactions
between stakeholders of the mobility ecosystem, modeling regulatory aspects
such as taxes and public transport prices, as well as operational matters for
Mobility Service Providers such as pricing strategy, fleet sizing, and vehicle
design. Our framework is modular and can readily accommodate different types of
Mobility Service Providers, actions of municipalities, and low-level models of
customers choices in the mobility system. Through both an analytical and a
numerical case study for the city of Berlin, Germany, we showcase the ability
of our framework to compute equilibria of the problem, to study fundamental
tradeoffs, and to inform stakeholders and policy makers on the effects of
interventions. Among others, we show tradeoffs between customers satisfaction,
environmental impact, and public revenue, as well as the impact of strategic
decisions on these metrics.
