But when they raised the idea of plug-in technology, the union of bus drivers voted against their members plugging in cables on health and safety grounds.

BBC: Wireless charging - the future for electric cars?

Toyota announced this week that it would be delaying plans to bring its plug-in, lithium-ion-based model to market until 2011, as opposed to 2008, due to safety concerns over the company's chosen battery.

ENGADGET: Toyota delays next-gen Prius while GM inks deal with lithium-ion maker