The problem, however, lies with what follows afterward. Fleets don't usually purchase vehicles year-round; once their batch of vehicles are built and delivered, they likely won't return for a new order for another 6-12 months. Automakers are then forced to rely more upon retail volumes, and those volumes at both GM and Chrysler haven't grown proportionately with fleet sales. Automotive News says GM's retail sales have slipped by less than 1 percent, while Chrysler's volumes have dropped by roughly 19 percent.

Other automakers have a much more favorable balance of retail and fleet sales. Hyundai's fleet sales comprise 16 percent of total sales figures; 9 percent of Toyota's volumes are tied with fleet purchases. Honda's fleet volumes are reportedly in the neighborhood of 2 -- yes, 2 -- percent.