The Union of Concerned Scientists thinks hybrid-electric vehicles are a good thing, because they use less gasoline.
But the savings in gas cost from that improved gas mileage varies enormously, and now the group has quantified the results.
In their annual Hybrid Scorecard this year, the UCS ranks hybrids on how much they reduce fuel consumption over comparable non-hybrid models.
It's an easy comparison for cars like the 2011 Ford Fusion Hybrid or 2011 Toyota Highlander Hybrid, since they're simply hybrid adaptations of regular gasoline models.
But it gets more confusing for so-called dedicated hybrids like the 2011 Honda Insight, the ur-hybrid 2011 Toyota Prius, and the new 2011 Lexus CT 200h compact luxury hybrid hatchback--which have no direct gasoline counterpart.
2011 Toyota Prius
As it was last year, the 2011 Toyota Prius was the top-scoring hybrid car, for its top-of-the-EPA-charts gas mileage of 51 mpg city, 48 mpg highway, for a combined rating of 50 mpg.
The UCS compared the Prius to a 2011 Toyota Matrix, which is also a five-door hatchback that can be ordered with a 1.8-liter four-cylinder engine.
The Prius mileage contrasts with the Matrix's ratings of 26 mpg city, 32 mpg highway, and a combined mileage of 29 mpg--meaning the Prius was 72 percent more fuel efficient.
After the Prius, the UCS lauded both the 2011 Ford Fusion Hybrid and the 2011 Honda Civic Hybrid for their substantial gas-mileage increases over their non-hybrid counterparts: 50 percent and 41 percent, respectively.
Luxury winners: Lexus, Lincoln
2011 Lincoln MKZ Hybrid
And, it turns out, those two cars--because of what they compare to--deliver even higher gas-mileage improvements.
At a combined 39-mpg rating, the MKZ Hybrid is the only four-cylinder model offered. It contrasts to the gasoline model, which has a 3.5-liter V-6 engine rated at only 21 mpg combined. In other words, it's 86 percent better.
Similarly, the UCS compared the 2011 CT 200h to a 2011 Lexus IS 250 sports sedan, the nearest comparable model in the Lexus line. The CT's combined rating of 42 mpg was 75 percent higher than the IS's 24 mpg.
No bare-bones hybrids
As it did last year, the UCS again slammed carmakers for loading luxury features into hybrids rather than offering stripped-down hybrid models that cost less.