What is 'Regenerative Braking' on modern hybrid or electric passenger buses?

1. The electric traction motor acts as a generator during deceleration, converting kinetic energy into electrical energy stored in the high-voltage battery while slowing the vehicle smoothly without brake wear
2. Using only the friction brakes while the traction motor is electrically isolated
3. Reversing motor torque to accelerate the bus in the opposite direction during every stop
4. Recovering all kinetic energy into the battery regardless of battery charge, temperature, or grip limits