Public transportation remains at the heart of any major city, but travel apps have quickly become a key means of getting around. However, many cities still struggle with congestion and air pollution despite the promise that new vehicle sharing services would reduce the number of cars on the road.

Taxi services now compete with ride-hailing giants for on-demand fares, and car-sharing schemes allow for private access to a vehicle that might otherwise be out of reach. All these new services rely on a smartphone, and in many cases, the willingness to share a ride. But as things stand, vehicle sharing services look to have become part of the very problem they seek to solve.

Bums on seats

The underlying concept of vehicle sharing is sound. Most cars travel around with empty seats that could be filled by other passengers, and thus are underutilised assets. If…