  Crowd-shipping is a promising shared mobility service that involves the
delivery of goods using non-professional shippers. This service is mainly
intended to reduce congestion and pollution in city centers but, as some
authors observe, in most crowd-shipping initiatives the crowd rely on private
motorized vehicles and hence the environmental benefits could be small, if not
negative. Conversely, a crowd-shipping service relying on public transport
should maximize the environmental benefits. Motivated by this observation, in
this study we assess the potentials of crowd-shipping based on metro commuters
in the city of Brescia, Italy. Our contribution is twofold. First, we analyze
the results of a survey conducted among metro users to assess their willingness
to act as crowd-shippers. The main result is that most young commuters and
retirees are willing to be crowd-shippers even for a null reward. Second, we
assess the potential economic impact of using metro-based crowd-shipping
coupled with a traditional home delivery service. To this end, we formulate a
variant of the VRP model where the customers closest to the metro stations may
be served either by a conventional vehicle or by a crowd-shipper. The model is
implemented using Python with Gurobi solver. A computational study based on the
Brescia case is performed to get insights on the economic advantages that a
metro-based crowd delivery option may have for a retailing company.
