E-commerce sales worldwide are expected to skyrocket in future years, increasing freight
traffic in cities. In this context, sidewalk autonomous delivery devices (ADDs) show great
potentialities to decrease carriers’ last-mile operation costs. Nevertheless, the
implementation of these autonomous robots requires some adjustments in the supply chain
because of their particular characteristics. To avoid severe accidents with pedestrians, their
speed and size will be limited and, as a consequence, ADDs seem more adapted to the
delivery of small items. The objective of this paper is to estimate the carrier’s total operation
costs in a dual delivery channel. If its size is lower than a given threshold, the parcel is
delivered to the customer through a supply chain compound of a logistics micro-hub and
ADDs. Otherwise, if the parcel is bigger than the given threshold, it is delivered through a
business-as-usual supply chain with delivery vans. The carrier’s total operation costs is the
sum of the costs induced by the two distribution channels. Assuming that the parcel size
follows a known probability distribution function, the carrier’s total operation costs are
estimated using the continuous approximation methodology. Different probability
distribution functions modelling the size of the parcels are studied in the paper. Finally, the
dual distribution channel is optimized considering the size threshold as a decision variable
of the system.
