Re: If you are going to describe a future, make it aspirational.
"Cars on autopilot can entrain with other autopilotted cars going in the same direction."
IIRC this was envisaged and trialled on closed test tracks at least 30 years ago.
I like the idea of an in-train charging vehicle though. On motorways and main trunk roads, multiple "trains" could be running all day the full length of the road as cars join and leave. With route planning, solar cells on the car roofs could supplement and distribute power to those in the train with the least charge or who are due to leave the train soon too.