Modular transit: Using autonomy and modularity to improve performance in public transportation

In this paper we investigate a new form of automated public transportation, named 'modular transit', configured to overcome the shortcomings of the traditional bus, including the first- and last-mile problem, low occupancy, and low levels of comfort, accessibility, and flexibility. The modular transit system consists of a set of trailer modules who can travel locally to serve demand and connect travelers to main modules for long-distance trips. We mathematically model this system on a time-expanded network, thereby reducing the size of the optimization problem and rendering the problem amenable to being solved with commercial optimization engines. We conduct extensive numerical experiments and sensitivity analyses to study the performance of modular buses under various configurations. Finally, we compare the modular transit service with a door-to-door shuttle service as benchmark to showcase the benefits of modular transit.