For fans of traditional model trains, success is the constant movement of cars that easily negotiate tracks and tableaus, traversing mock villages, waterways, and places of business.

Modern mobility proponents — a group that includes cities around the world — seek perpetual motion, too, using both established forms of transit and new ones: ride sharing, free-floating bikes and scooters, and more. They aim to create a large-scale real-world version of that toy train vision, one that allows people to move quickly and seamlessly through metropolitan areas. Someone living in a suburb, for instance, could travel easily to work in a city, using an app that allows her, with a single click, to book and pay for, say, a shared autonomous electric vehicle that will take her from her doorstep to a train with a stop near her office.

This kind of access is called mobility as a service. MaaS enables end-to-end transit using the new mobility offerings that are proliferating in cities around the world as well as traditional modes like public transportation and taxi services. It relies on a digital platform to support all aspects of commuter journeys, from planning to optimized transit.