Cyber wrote:
"I took a test drive with an EV1 (back before they cancelled all the leases and crushed the cars), and they had a feature that used a generator from the wheels when you took your foot off the "gas" pedal as you approached a traffic signal. It slowed the car down without using the brakes, and pushed more charge into the battery. It was to help extend the range. I assume modern electrics have this feature."
The Prius has this feature. It can use the car's motors to "re-generate" power during braking and recharge the batteries.
"Regenerative" or "dynamic" braking has been a feature of railroad locomotives since the early years of the 20th century.
By switching the traction motors into generators, electric locomotives could "put power back into the wire" on downgrades through regeneration.
Diesel engines used dynamic braking, in which the motors also acted "as generators", but the generated power (no wire overhead) was "burned off" by way of resistance grids.
The dynamic could hold back the weight of a freight train on a downgrade, sometimes without even having to use the train air brakes at all.
With passenger trains, there's something called "blended brake" where dynamic and air is used together to slow the train rapidly. This is done automatically, the engineer doesn't have to control them separately.