public transportation with logistics services

two-tired model for a shared passengers & goods city logistics system. In the first system tier, goods are collected at a facility called the City Distribution Center (CDC). From CDC, goods are then loaded on buses, through the connection with the bus line. By mixing the two flows, passengers have priority. Goods, packed in roll containers, are loaded on the spare capacity of the bus. The suggested shared transportation model has to ensure the quality of service to passengers using public transport. In the second system tier, goods are unloaded at identified bus stops where they are transhipped to capillary logistics system using tricycles that deliver customers through near–zero emissions city freighters. This approach is much more flexible. It offers the advantage to adjust at any time the number of tricycles available at bus stops. Furthermore, delivery vehicles are synchronized with buses and ensure the transhipment operation, and avoid the installation of storage facilities at bus stops. 2. Suggest a model to dimension the number of tricycles allowing the satisfaction of the daily customer demand. We propose a heuristic method to solve the optimization problem formulated as a special case of two-echelon vehicle routing problem with transhipment.