  Complex systems like human mobility exhibit a wide range of collective
dynamics. Ride-sharing, the combination of multiple similar trips into one, is
a particularly prominent example due to the complex interplay between the
requests and the vehicle fleet. Several contributions have analyzed the
dynamics of the routing and the service efficiency of ride-sharing fleets.
Here, we adopt a complementary perspective and study the adoption of
ride-sharing from the perspective of its users. Collective interactions of the
users to avoid detours in shared rides give rise to spontaneous symmetry
breaking, pattern formation dynamics, and bistability, potentially limiting the
adoption of ride-sharing. Our results may provide a framework to understand
real-world adoption patterns of ride-sharing in complex urban settings and
(re)design ride-sharing services and incentives to promote sustainable shared
mobility.
