Integrated Line Planning and Strategic Ridepooling: Minimizing the Passengers' Travel Time

Abstract

Public transport systems increasingly combine fixed-line services with demand-responsive transportation such as ridepooling. In this paper, we present an integrated optimization model for line planning and strategic ridepooling that explicitly incorporates passenger routing into the planning process. Building on previous work on integrated line planning and strategic ridepooling as well as Change&Go networks, we develop a model for the integration of line planning and strategic ridepooling that minimizes the total travel time of all passengers while respecting a given budget. The resulting mixed-integer optimization model simultaneously determines line frequencies, ridepooling capacities, and passenger routes, capturing interactions between the two different transportation modes – one line-based mode and one mode without fixed lines and timetables – and still accounts for travel times, transfer times, and capacity decisions within a single optimization model. Focusing on an applicable model, we show how the data structure of an existing line planning model with integrated passenger routing in a Change&Go network can be improved, rendering the problem solvable for medium-sized instances. We consider the optimization model as a bi-criteria problem with the objective functions of travel time and operating cost, and compute pareto-optimal solutions with a budget constraint method. Our computational experiments on benchmark instances demonstrate the applicability of the model and show that integrating passenger routing into the strategic planning process yields multimodal transport systems that dominate solutions from approaches based on fixed routings.