Buses that charge their batteries off overhead trolley wires while moving, and operate like other battery electric buses off-wire, can cover the same distance in a day as a diesel bus. And the overhead wires only need to cover between one-fifth and two-thirds of the route, so costs are not much more than burning diesel. Battery trolleybus technology is well proven; the system in Rome has been in operation since 2005.
The cities in the best position to quickly shift to electric buses are those that already have trolleybus wires in place.
Cities with existing trolleybus wire networks (such as Lyon, Vancouver, Seattle and San Francisco, Shanghai and Bejing, and over 300 other trolleybus cities around the world) already have powerful charging systems in place for electric buses.