Most people have an aversion to car sharing. Most people also have an aversion to fuel price-induced poverty…not to mention the damage which road transport does to the environment and our health. So we will increasingly have to choose to travel with other people (whom we may not know).
Today’s invention is therefore a modification to the electric urban vehicle of the future. We can get away with about 1/4 as many of these roaming the streets by building them so that they will only move when occupied by four people.
This could be detected by a hard-to-fake combination of bodyweights in seats, heartbeats recorded via seatbelt sensors and fingerprint-reading door handles.
To make a journey in such a vehicle, you would go to a stop and indicate your destination on a touchscreen. If you hadn’t bothered to coordinate with three friends, others waiting at the stop could then join you for parts of the journey along a designated route.
If someone got out before your end-point, you might have to wait at that stop until someone else wanted a ride on the same route. This alone would encourage people to finish an increasing proportion of journeys on foot.
Once these vehicles were in place, it might be possible for say two occupants to agree to pay a hefty surcharge to be allowed to travel without others on board.