UNDATED (CNN) -- Chevy Volt sales are cranking up. General Motors sold over 23,000 Chevrolet Volts in 2012.
Those sales put the Volt well ahead of its nearest competitor, the Nissan Leaf.
Industry and GM analysts say the biggest factor driving sales is the vehicles increased popularity in car-clogged California.
Engineers apparently tweaked the Volt making it eligible for California's highly desirable carpool lane stickers.