In the meantime, it's begun testing prototypes in "extreme" conditions, like the icy roads of the Arctic circle and on the sweltering tarmac in Spain's Sierra Nevada. The move comes just days after its parent company Daimler unveiled its electric school bus, further emphasizing its commitment to electric public transportation.

The "ultra quiet" bus is powered by modular, lithium-ion battery packs that fuel the electric wheel hub motors at the rear axle. The company also touts its energy-efficient climate control system as a range booster. But, it will have its work cut out to beat EV manufacturer Proterra -- which recently set the record for longest distance traveled by an electric bus on a single charge (a whopping 1,101.2 miles). It's also facing competition from Navya, the French firm behind the Las Vegas driverless shuttle service that just started back up (albeit with a hiccup). Not to mention household names like Volvo and Toyota.