LOS ANGELES — Ann Deren-Lewis thought it would be hard to give up her Jeep Cherokee — she saw SUVs everywhere she went. Then a new job 40 miles away got her thinking about guzzling gas.

Out went the Jeep and in came a Honda Civic running on compressed natural gas, an alternative fuel cheaper than gasoline. Her car isn't a hybrid, the increasingly popular vehicles fueled by gas and electricity; environmentalists say it's even better.

"I'm driving a car that doesn't put any bad things into the environment, it's cheap to operate and maintain," Deren-Lewis said. "And it's comfortable."

But despite the enthusiasm of drivers like Deren-Lewis, automakers are retreating from vehicles that run on natural gas or electricity. Automakers say there's little buyer demand for so-called "alt-fuel" vehicles; environmentalists say automakers aren't trying hard enough to market them.

Meanwhile, hybrids such as the Toyota Prius are flourishing. At the 2005 North American Auto Show in Detroit, automakers touted hybrid SUVs and sedans. About 88,000 hybrids were sold in the United States last year, according to J.D. Power and Associates, which projects the number to more than double to about 220,000 this year.

Alternative-fuel vehicles never caught on like that — it took about seven years for their number to double, according to federal statistics. As of 2002, Americans drove an estimated 471,000 alternative-fuel vehicles (including those powered by electricity, natural gas, propane, ethanol and methanol), the U.S. Energy Department said — up from 247,000 in 1995.

It's still a fraction of the more than 15 million new vehicles sold annually in the United States.

Environmentalists say any vehicle that uses less gasoline is a good start. But many wonder why automakers don't focus more on promoting alternative-fuel vehicles.

"Watch television or listen to the radio, you're bombarded with ads for gas-powered vehicles," said Andy Weisser, a spokesman for the American Lung Association of California who bought a natural gas vehicle out of concern about air quality. "I have never seen a natural gas vehicle ad."

Deren-Lewis, a marketing executive at beauty products maker Neutrogena, only learned about natural gas cars after the company offered incentives for alternative-fuel drivers.

Internet research and word of mouth led her to a seller. "You don't just pull into a Honda lot and say, 'Can you get me one of these?' " she said.