Prius V

There's no doubt that the Toyota Prius has been a hit. A year ago, worldwide sales of the hybrid hatchback passed two million and, with annual sales of over 400,000 units, the Prius practically defines the idea of a green car for many people. Toyota is expanding the Prius from a model into a family with the larger Prius V, a plug-in model coming next spring and a smaller model on the way. Toyota had projected that 2011 would be another banner year, with record sales of the Prius leading the way.

However, sales of the Prius in 2011 haven't kept pace with expectations. Sales of the Prius actually dropped 9.4 percent from October 2010 to October 2011.

Part of the reason could be demand. Since the car's introduction, sales have gone up and down with gas prices, and while prices at the pump are considerably above where they were a few years ago, consumers have become accustomed to $3 a gallon gas. With the worldwide economic slowdown depressing the demand for oil, gas prices have failed to reach the stratospheric heights some had predicted. Other hybrids, such as Honda's Insight and Ford's Fusion Hybrid saw even greater declines.

Still, Toyota lays the blame for declining Prius sales on a lack of supply, not demand. The Japan earthquake closed down Prius production for nearly 90 days and put a big crimp in the delivery pipeline. With that issue behind them, Toyota is counting on increasing Prius sales in 2012 to power the lineup. In addition to record numbers for the existing Prius and the new Prius V crossover, Toyota is expected to sell over 16,000 of the plug-in model in its first year of availability.