DETROIT -- Industry insiders and observers are awaiting, with some skepticism, details of a forecast that predicts America’s roads will, by mid-decade, be home to 500,000 vehicles powered by gasoline-electric hybrid engines.

The forecast, researched by J.D. Power and Associates, will be published Dec. 10. It also says there will be 20 hybrid models on the market by the time registrations reach the half-million mark.

Of the prediction, American Honda Motor Co. Inc. spokesman Art Garner says: “That’s a lot of hybrids.” Asked if the 500,000 total is attainable, he repeats: “That’s a lot of hybrids.”

Toyota Motor Corp. says it hopes, by 2005, to sell 300,000 hybrid units annually. But that’s worldwide. And there are fewer than 30,000 on the road today.

However, the lineup of hybrids set to debut in coming months lends credence to the bold prediction by J.D. Power.

Insight, darling of the Environmental Protection Agency’s fuel efficiency ratings since 1999, will be joined in the Honda stable this spring by a hybrid Civic. The Civic HX will debut in the U.S. next month at a conference hosted by The Electric Vehicle Association of the Americas (EVAA). Volkswagen AG also will show a hybrid Jetta.

Toyota, along with Honda, is one of only two automakers with a hybrid currently on the U.S. market. The automaker is coy about its future hybrid plans but a spokesman hints -- against a backdrop of two unveilings in Japan -- that more will soon arrive on American soil.

Meanwhile, Ford Motor Co. is introducing a hybrid-powered Escape in 2003, although reports persist that the No.2 auto maker has scrapped plans to build an Explorer with a fuel stingy integrated starter-generator (ISG) system. General Motors Corp. and DaimlerChrysler AG have hybrid pickups on their horizons, and the latter also promises a hybrid-powered Durango in 2004.

Research on the growth of the “green” sourcing for stationary power suggests a slow ramp-up for hybrid-powered autos.

“The big variable in dealing with hybrid automobiles and a lot of these, sort of, environmental products, is you’re almost entirely relegated to an environmental value proposition,” says Ryan Wiser of the Lawrence Berkeley National Laboratory. “You don’t have a product that necessarily has higher quality than alternative products.

“It seems to me, of critical importance for the hybrid auto market is not so much acceptance among the environmental populace -- I mean, that’s certainly what’s driving sales today -- but to get to the large penetration rates that many of us hope for, you’d have to look for a value proposition that exceeds the environmental one.”

Meanwhile, a Roland Berger study on consumer attitudes toward hybrid technology is generally favorable. It urges automakers to forge ahead with development, adding the market represents “an excellent opportunity” for suppliers to increase revenues and profitability.

But, the study warns, a key issue must be addressed: “Is our pricing strategy appropriate; will it help or hurt our sales performance? Is our cost structure under control for hybrid vehicles?”

Eric Mayne’s e-mail address is