Where to change from public transportation to car-sharing? Developing a transfer point optimization method

The combined use of public transportation and car-sharing in the urban environment can provide a competitive alternative to private transportation. Public transportation, particularly the rapid rail network, provides quick access to the downtown while car-sharing services offer flexibility and convenience in the outer districts. Combined journeys can combine the benefits of both transportation modes, especially if transfers between them can be managed smoothly. We defined the Travel Chain Indicator to evaluate travel chains in terms of travel time and cost. To select the optimal transfer point, we used the TOPSIS method, which allows for ranking the evaluated indicators and choosing the best alternative. The method developed was tested in a case study in Budapest, considering a metro line and seven destination points in an outer district further from the metro line that can be reached by car-sharing use. The results showed that combined modes offer the best solution when time and cost criteria are defined with similar weights. The method developed can be used for route optimization and service area development for car-sharing operators, identifying the areas where multimodal travel is a competitive alternative.