actually some vehicles to regernative braking, slowing engages a fly
wheel that spins up, rather than braking by using calipers and pads,
whoase waste energy is heat/
the feds had a dumb idea, put windmills along roads, cars passing by
would make the mills spin generating power.
which unfortunately would slow the vehicles, and be a hazard.
the idea died before they spent a gazillion dollars trying it out