WASHINGTON - Even though the price of a gallon of diesel has climbed more than 20 percent in the past 12 months, diesel cars still offer better gas mileage and savings than regular cars. That’s because diesel engines are more efficient than gas engines, delivering up to 25 percent to 30 percent more miles per gallon, according to www.businessweek.com.

Audi, BMW, Mercedes-Benz, and Volkswagen are launching a wave of new clean-diesel cars in the United States starting this fall and into 2009 and beyond. Domestic and Asian manufacturers also have plans to offer more diesels in the U.S. market.

A year ago, when diesel fuel was cheaper than regular gas, the diesel model would have saved almost an average $500 a year in fuel costs, based on 15,000 miles a year, at the EPA highway mileage estimate. Today, because diesel fuel is so much more expensive and because the mpg advantage for diesel Jeep Grand Cherokee is only about 15 percent, the diesel model would actually cost about $100 a year more to operate than the gasoline model, according to www.businessweek.com.