The idea of a magnetic coupling between the engine and the passenger compartment is very interesting. This could be adapted to use with self-driving automobiles on highways. They could run on their own electric power train for local journeys, then pick up a "thrust carriage" when joining a highway. This pulls them along until their exit, when they decouple and return to using their battery and on-board motors. The on-board motors could also take over for short sections for example between different thrust carriage runs.

Perhaps the thrust carriage control systems could be made smart so they automatically maintain safe spacing between vehicles and adapt their speed to the volume of traffic. They'd communicate with the vehicle to tell them when the coupling was about to end so that the vehicle can engage its own drive train to take over smoothly. Or the vehicle's self-driving systems tell the thrust carriage how fast to go depending on the traffic conditions.

This could massively extend the range of electric cars. Burying the pipes in the road network would obviously be very expensive, but the size mentioned in the article (12 inch diameter) is not prohibitive.