Buffalo, N.Y. -- General Motors Co. is now 1 million miles into its fuel cell experiment and company officials say having everyday people drive a test fleet of pollution-free cars has convinced them they are on the right track.

The automaker on Friday said it passed the 1 million-miles-driven mark in its fuel cell Chevrolet Equinox vehicles, with about 5,000 people rotating in and out of more than 100 cars over the past 25 months.

"They'll tell you that after the first week, they pretty much forget it's a fuel cell car, which indicates to us that we have accomplished our goal of making the fuel cell transparent to the consumer," said Daniel O'Connell, director of fuel cell commercialization at GM's research and development offices in Honeoye Falls, near Rochester.

"They get in the car and drive it like they've always driven their cars, and that really tells me that fuel cells are closer than most people would believe," he said.

Supporters see the fuel cell becoming a mainstream, eco-friendly alternative to petroleum-powered cars within the next decade. Powered by electricity, generated by a reaction between oxygen and hydrogen, the only emissions are wisps of water vapor.

"You put your hand over the exhaust pipe and the only thing coming out is water. That was such a cool feeling," said Mike Schwabl, a marketing executive who drove an Equinox for 10 days in western New York earlier this year. Other drivers tried cars in Washington, D.C., and southern California.

The cars look and handle like any other car, Schwabl said. "I would love to drive one of these vehicles (permanently)."

But numerous obstacles remain for GM and its competitors in the fuel cell race. Toyota Motor Corp. introduced a car powered by hydrogen and electricity last year and will introduce an improved hydrogen fuel cell vehicle in 2015. Daimler AG has spent nearly $2 billion and plans to spend another $700 million by 2011 for the commercial production of fuel cell vehicles, while Honda has leased a small number of FCX Clarity vehicles in California to assess hydrogen's future.

Auto companies do not disclose costs, but the vehicles are expensive to produce because most are hand-built prototypes. Also, the nation lacks a network of fueling stations.

Improving technology should allow the next cars to go farther than the current 168 miles per fill-up, O'Connell said. Until then, drivers have to keep a close eye on the fuel gauge to avoid drifting too far from one of about 70 fueling stations in the United States.

Test driver Laurie DeRoller learned that the hard way, stalling out five miles short of the filling station in Honeoye Falls during a weekend test drive in May. GM sent a flatbed to take it away.

"It was a rural road, we're talking cars that are mostly farmland type vehicles and people are driving by, and here's myself on the side of the road with the fuel cell car," said DeRoller, executive director of the International Business Council of Greater Rochester. "And people are slowing down and looking," she laughed.

The experience didn't change her mind about wanting to own one, she said, and she felt confident a hydrogen highway will eventually exist. Refueling the cars with compressed hydrogen takes about five to seven minutes in a process similar to putting gasoline in a traditional car.

"I was the only parent allowed to idle my car in the pickup line at school," said Jeanine Behr-Getz, a Greenwich, Conn., author whom GM identified as having driven the millionth fuel cell mile.

"We've learned that the technology can be accepted by the consumer and that it is a viable means of powering our automobiles of the future," O'Connell said of the "Project Driveway" test.

He said the program will continue for five more months and then the cars will be pulled off the road and upgraded with technology developed while they've been in use.

GM's research and development offices in Honeoye Falls, near Rochester.