Modeling framework for the agent-based simulation of rail-based urban parcel transport: An application of a two-stage transport chain selection model in the city of Karlsruhe, Germany

In recent years, innovative city logistic concepts for courier, express, and parcel (CEP) shipments have raised particular interest in contributing to a more sustainable transportation system. One solution can be the utilization of existing urban rail infrastructure. A so-called ‘cargo tram’ transports goods to an intermodal city hub, where cargo bikes cover the last leg to the receiver. Although conceptional or economic studies exist, detailed analyses of the transport-related effects, e.g., through freight demand models, still need to be carried out. Hence, in this study, we develop a methodology to integrate urban rail-based parcel transport in terms of a cargo tram into the existing agent-based freight, i.e., parcel, demand model logiTopp . Instead of a single mode choice, a two-stage selection model based on transport chains is developed, comprising a rule-based and utility-based stage. The proposed methodology is implemented in logiTopp , and the model is applied to the city of Karlsruhe, Germany, where the overall effects of rail-based parcel transport are simulated and evaluated in proof-of-concept scenarios. The analysis shows that the proposed transport chain selection model produces overall reasonable results. Moreover, they indicate that the realization of a rail-based parcel transport can reduce the overall mileage and number of trips caused by CEP shipments. However, the potential is driven by several factors, such as the number and location of city hubs, the maximum range of cargo bikes, and the overall evaluation of the cargo tram. Additional empirical investigations are necessary to validate the results from the proof-of-concept scenarios.