  Ride-sharing services are gaining popularity and are crucial for a
sustainable environment. A special case in which such services are most
applicable, is the last mile variant. In this variant it is assumed that all
the passengers are positioned at the same origin location (e.g. an airport),
and each have a different destination. One of the major issues in a shared ride
is fairly splitting of the ride cost among the passengers.
  In this paper we use the Shapley value, which is one of the most significant
solution concepts in cooperative game theory, for fairly splitting the cost of
a shared ride. We consider two scenarios. In the first scenario there exists a
fixed priority order in which the passengers are dropped-off (e.g. elderly,
injured etc.), and we show a method for efficient computation of the Shapley
value in this setting. Our results are also applicable for efficient
computation of the Shapley value in routing games.
  In the second scenario there is no predetermined priority order. We show that
the Shapley value cannot be efficiently computed in this setting. However,
extensive simulations reveal that our approach for the first scenario can serve
as an excellent proxy for the second scenario, outperforming other known
proxies.
