Fuel cell vehicles are reaching a milestone this week. General Motors, the owner of Chevy, says there will be 100 Chevrolet Equinox Fuel Cell cars on U.S. roads by Friday as part of the company’s ongoing Project Driveway initiative.

Private individuals, corporations and governmental agencies, including Disney, Virgin Airlines and the Environmental Protection Agency, which received its car on Friday, are participating. These participants are supposed to use--or is that abuse--the cars just as they would the old bangers normally in their driveways. Day after day.

This will give GM engineers valuable information about durability and reliability, especially in cold weather, one of the technological sticking points still holding back mass production of fuel cell vehicles.

Fuel cell vehicles, which run off electricity generated through a chemical process using hydrogen fuel and oxygen from air, are often touted as the end game for alternative fuel cars. But they have serious hurdles to overcome before they become a viable option for the masses. Those challenges include cost, onboard hydrogen storage and safety.

Another hurdle is the distribution network for hydrogen. The three metropolitan areas for Project Driveway, which launched in November 2007--New York, Washington D.C. and Los Angeles--were at least partly chosen based on the availability of the fuel.

One more hurdle is less tangible--public acceptance. Consumers have concerns about the dependability and safety of fuel cell vehicles, according to fueleconomy.gov, a Web site run by the U.S Department of Energy and the EPA.

GM appears to be making some headway in this area as well. Spokeswoman Carolyn Markey said more than 70,000 people have applied to participate in the project. Many more no doubt will have heard about it. They will see the cars in media or on the road, or will talk to a participant over dinner or a drink. In short, Project Driveway is getting the word out that fuel cell vehicles aren’t just science fiction.

The project is certainly not philanthropic, and GM stands to gain enormously if it can emerge as a leader in the burgeoning market. That’s why it has attached the new car, in its fourth generation, to its most prolific brand, Chevy.

But it will still be several years before Chevrolet Equinoxes are cranking off the assembly line. Markey said GM expects them available sometime early “next decade.” Meanwhile, major rivals are tinkering away on their own fuel cell vehicles. Honda has its FCX Clarity, which is now being leased to limited private individuals in what appears to be a similar program to GM’s. And Toyota has its creatively named FCHV, or Fuel Cell Hybrid Vehicle, also still in development.