Combined Passenger and Cargo Transport: A Hybrid Simulation and Optimization Approach Focusing on the Transshipment of Cargo Between Tram Vehicles

AbstractOffering a promising opportunity for cargo transport in urban areas, cargo is transported along with passengers sharing the same infrastructure and vehicle. Cargo must be routed efficiently through the network and assigned to vehicles. The resulting problem can be modeled as a network flow problem. Additionally, constraints such as varying capacities due to fluctuations in passenger numbers during the day must be considered. These numbers, as well as the demand for cargo transports, are assumed to be stochastic and therefore considered in a simulation study. To solve this problem, a hybrid simulation and optimization approach are presented. The deterministic network flow problem is solved to optimality with the help of a commercial solver. A simulator uses this solution to assign transport units to vehicles and determine a route through the network. As soon as the solution becomes infeasible, the deterministic problem is resolved with the current parameters. The new solution serves once again as an input for the simulation. This approach is expected to be more efficient compared to considering scenarios for every possible form of uncertainty.KeywordsFreight on transitPublic transportSimulationOptimizationUrban logistics