I think the way my Bolt does regen braking in 'single pedal driving' mode is the way to do delivery trucks. In that mode you almost never use the brakes, it uses regen back-pressure from the motors to stop you. As you let off the accelerator it slows you down. The more you let off, the faster you slow down. If you're stop-starting down the street, I think you'd capture back quite a bit of the power from the little bit of accelerating you're doing between mailboxes or buildings.