ABSTRACT Negative externalities refer to costs arising from transportation activities that are not borne by service providers or consumers, often leading to their neglect in freight transportation planning. This study proposes a novel framework for optimising water‐road transportation route selection by incorporating two key negative externalities: fuel consumption and traffic risk. Traffic risk is assessed using a safety performance function, while fuel consumption is estimated based on the Handbook of Emission Factors for Road Transport. The proposed framework is applied to California's road network and port system, where the optimal operation area for each major port is determined and compared across different optimisation objectives: trip distance, fuel consumption and traffic risk. Results indicate that the optimal operation area varies significantly depending on the relative weight assigned to each objective. The findings demonstrate that optimising routes beyond just minimising distance can reduce fuel consumption and traffic risk, highlighting the substantial differences in optimal operational areas under different criteria.
Zhang et al. (Wed,) studied this question.