General Motors Corp. will begin road testing its Chevrolet Volt plug-in hybrid in the spring of next year and remains on track to produce the rechargeable car by late 2010, a senior executive recently said, CNN Money reports. As the race to bring a mass-market, rechargeable electric vehicle to the market heats up, GM's global product chief Bob Lutz said he expects to have next-generation lithium-ion battery packs ready for the vehicles by October this year. GM is the only automaker to have provided a timeline on the production of a plug-in hybrid vehicle, even though other companies, such as Ford Motor Co. and Toyota Motor Corp. are working on similar technology. Automakers have said lithium-ion battery technology remains the biggest challenge in producing a plug-in vehicle as they try to lower the cost of the batteries and increase their power and storage capacity.