Cars from Honda Motor Co., Toyota Motor Corp., Hyundai Motor Co. and Kia Motors Corp. occupy 10 of the top dozen spots in the annual "green car" survey to be released today.
But only three of the most environmentally friendly vehicles are gas-electric hybrids because advances in fuel economy and emissions controls have boosted conventional cars onto the list, compiled by the Washington-based American Council for an Energy-Efficient Economy.
General Motors Corp., the only American carmaker in the top 12, placed three models, all with conventional engines.
GM's greenest model, however, is the Pontiac Vibe, which uses a Toyota engine and emissions system. The Vibe tied for 10th place with its Toyota twin, the Matrix. Chevrolet's Cobalt and Saturn's Ion, both compact sedans, finished 11th and 12th.
The top-ranked model was Honda's Insight, a rarely sold two-seat hybrid with an automatic transmission.
The Insight squeaked past last year's leader, the natural-gas-powered Honda Civic GX, because it gets much better gas mileage, said study author James Kliesch. Both cars scored 57 on the council's 100-point green car scale.
Toyota's Prius hybrid, Honda's Civic hybrid and a conventional gasoline model of the Toyota Corolla rounded out the top five, as they did last year.
The council's Green Book (www.greenercars.com) rates 459 passenger vehicle models available to consumers for the 2006 model year.
The "green scores" are based on federal fuel economy estimates, average annual fuel costs and California or federal emissions ratings, along with an industry average for pollutants from manufacturing and pollution-related public health costs.
For the second year, the least environmentally sensitive vehicle was DaimlerChrysler's Dodge Ram SRT-10. The high-performance pickup truck is powered by a 10-cylinder gas engine and has an EPA fuel economy rating of 9 miles per gallon in the city and 12 on the highway.