NEW YORK (CNN/Money) - A Ford SUV took a place among the "greenest" vehicles in this year's "greenest and meanest" list from the American Council for an Energy-Efficient Economy (ACEEE).

Another Ford SUV, the extra-large Excursion, earned second place on the group's "meanest" list of the least-environmentally friendly vehicles.

The ACEEE publishes an annual "Green Book," a guide which ranks vehicles according to their impact on the environment. The Ford Escape Hybrid, powered by a four-cylinder gasoline engine bolstered by an electric motor, came in at number 11 on the list of the most environmentally friendly vehicles. With an estimated city mileage of 36 and highway mileage of 31, the Escape Hybrid got a score of 40 under the ACEEE's rating system.

ACEEE rates vehicles on a 0-100 scale with higher scores indicating a lower environmental impact. The average car has a score of 33 and the average truck has a score of 21 under the ACEE's rating system which takes into account mileage as well as the types and amounts of pollutants produced by each vehicle.

"For years, we've been advising buyers that greener models are available to them no matter what type of vehicle they're shopping for. Today, with a bona fide gas-powered SUV on our Greenest Vehicles list, this advice rings truer than ever," said author and principal vehicle analyst James Kliesch, a Research Associate at ACEEE.

The top six "Green cars" were:

Honda Civic GX, a natural gas-powered car that gets an estimated 30 miles per gasoline-gallon-equivalent in the city and 34 miles per gasoline-gallon-equivalent in highway driving. Because natural gas releases very little pollution when burned, the GX's "Green score" is 57 out of a possible 100, the highest of any vehicle. The GX is currently sold only for fleet use, but Honda does plan to sell them to private consumers in the future, according to Chris Naughton, a Honda spokesman.

Honda Insight, a two-seat gas-electric hybrid vehicle that is estimated to get 57 miles to the gallon in city driving and 56 miles per gallon on the highway. Its "Green score" is 56. Gas-electric hybrids use an electric motor, running off a battery charged by the car's gasoline engine, in addition to the driving power of the gasoline engine.

Toyota Prius, a mid-size gas-electric hybrid sedan that gets an estimated 60 miles per gallon in the city and 51 miles per gallon on the highway. (As with most cars, Prius drivers generally report lower actual mileage than the EPA estimates.) The Prius's "Green score" is 53.

Honda Civic Hybrid, a gas-electric hybrid version of the Civic small car. The Civic Hybrid gets an estimated 47 miles per gallon in the city and 48 in highway driving. Its "Green score" is 51.

Toyota Corolla, a small car powered by a 1.8-liter 4-cylinder engine. The Corolla gets an estimated 32 miles per gallon in city driving and 42 miles per gallon on the highway. Its "Green score" is 44.

Toyota Echo, a small, light economy car with a 1.5 liter 4-cylinder engine. It gets 35 miles per gallon in the city and 42 miles per gallon on the highway. Its "Green score," 43, is slightly lower than the Corolla's because the Echo emits more smog-forming pollutants, according to the ACEEE.

The top six "Mean cars" were:

Dodge Ram SRT10, a high-performance version of the Dodge Ram full-sized pick-up. This truck is powered by an 8.3-liter 10-cylinder engine. The Ram SRT10 is estimated to get nine miles per gallon in city driving and 12 miles per gallon on the highway. Its "Green score" is 11 out of a possible 100.

Ford Excursion, the company's largest SUV. The Excursion is being discontinued after the 2004 model year. Because of its extemely large size, the Excursion is exempt from EPA regulations on passenger vehicles. It is estimated to get 13 miles per gallon in city driving and 17 miles per gallon on the highway. Its "Green score" is 13.

Hummer H2, like the Excursion, is exempt from EPA regulations on passenger vehicles. Its estimated to get 13 miles per gallon in the city and 17 on the highway. Its "Green score" is 13.

Mercedes-Benz G55 AMG, a limited-edition, performance-tuned version of the company's most expensive SUV. The G55 is estimated to get 12 miles per gallon in the city and 14 miles per gallon on the highway. Its "Green score" is 13.

Lamborghini Murcielago, an exotic sports car that sells for about $300,000. The Murcielago is powered by a 6.2-liter 12-cylinder engine. About 120 are sold in this country every year, according to a Lamborghini spokesman. The Murcielago is estimated to get 9 miles per gallon in the city and 13 on the highway. Its "Green score" is 14.

GMC Yukon XL K2500, a large SUV. Like the Ford Excursion and Hummer H2, this vehicle is exempt from EPA fuel economy regulations that apply to passenger vehicles. It is estimated to get 13 miles per gallon in city driving and 17 on the highway. Its "Green score" is 14.