A Novel Real-Time Coordinated Ridesharing Route Choice Mechanism

Ridesharing service, as a sustainable transportation mode, has gained great interest in both industry and academic fields. Existing TNC ridesharing services provide prescriptive solutions without coordinating riders’ interactions and intentions on route choices. As a result, ridesharing services often end with ride-hailing services, and they are still under a relatively low usage rate. Motivated by this view, this study developed a real-time coordinated ridesharing route choice mechanism (CSM) for guiding riders’ ridesharing route choices to fill this research and application gap. Specifically, this study modeled this CSM as a pure-strategy atomic fare-sharing game based on the assumption that every rider is selfish and tries to choose the best route to minimize his/her travel fare among multiple feasible candidate routes. An existing tree-generation algorithm was used to find the candidate routes for each rider. This study proved the existence of a Nash Equilibrium in this game by constructing a potential function and proving this game is a potential game. This study further developed a sequential updated distributed algorithm and proved its convergence to explore an equilibrium solution of the CSM. To address the scalability issue, this study created a coalition formation approach based on ridesharing potential, to separate riders into ridesharing coalitions and then independently implement the CSM for each ridesharing coalition. Our experiments illustrate that the coalition approach scales down the problem size of each CSM and dramatically improves the computation efficiency while maintaining the same level of system performance. More importantly, the CSM can significantly promote riders’ usage of the ridesharing service by greatly saving their travel fares while satisfying their trip requirements.