Synchronizing Public Transport Transfers by Using Intervehicle Communication Scheme Case Study

Synchronized transfers in public transport (PT) networks play an important role in reducing transfer walking time, increasing PT network connectivity, and improving PT reliability and the attractiveness of the PT service. However, because of the dynamic, stochastic, and uncertain nature of traffic, planned synchronized PT transfers do not always materialize. Missed connections frustrate the PT passengers and reduce potential new users. This research proposed an intervehicle communication (IVC)-based scheme to optimize the synchronization of planned transfers in PT networks. A semidecentralized control strategy was developed for the IVC systems to make the optimization a parallel process. Two operational tactics, changing vehicle speed and holding vehicles at transfer points, were used in the optimization with real-time vehicle speed and location information. A distance-based dynamic speed-adjustment model was developed for updating vehicle running speed under the fixed single-point encounter scenario and flexible road-segment encounter scenario. The impact of the proposed IVC scheme on the total number of direct transfers and the total passenger travel time (TPTT) was investigated with a case study of a PT network from Beijing. Results showed that by applying the proposed methodology, the number of direct transfers was considerably increased by 1,100%, and the TPTT was significantly reduced by 13.2%