The About.com test drive team rates each vehicle on a basis of 1 to 5 stars. Here's what the stars mean:
1 star: Doesn’t offer much as an alt fueler/hybrid2 stars: Much better options available in this alt fuel/hybrid segment
3 stars: Right on par with others in this class
4 stars: Stands out among its alt fuel/hybrid rivals
5 stars: An exemplary example of what an alt fueler/hybrid should be
An additional half-star may be awarded at the writer's discretion.