Developing a large-scale taxi dispatching system for urban networks

Taxis are increasingly becoming a prominent mobility mode in many major cities due to their accessibility and convenience. The growing number of taxi trips is cause for concern when vacant taxis are not distributed optimally within the city and are unable to find waiting passengers effectively. A way of improving taxi operations is to deploy a taxi dispatch system that considers the interrelated effects of taxis on other traffic modes. This paper presents a taxi dispatch model that takes into account the impact of taxis on normal traffic flows while optimizing for an effective dispatch policy. The presented model builds on the concept of the macroscopic fundamental diagram (MFD) to represent the dynamic evolution of the traffic conditions. A model predictive control approach is devised to control the taxi dispatch system on a two-region city case study. The results show that the case of no network-scale taxi dispatching leads to severe accumulation of taxi passengers and vacant taxis in different regions whereas the dispatch system improves the taxi service performance and reduces traffic congestion by regulating the network towards the undersaturated condition.