Fans of the hybrid car, take note. The rest of you might want to pay attention, too.

Starting tonight, a four-man driving team will attempt to achieve the highest mileage-per-gallon ever recorded in the sporty Toyota Prius: 100 miles per gallon.

The men -- Dave Bassage of Walton, W.Va., Dan Kroushl of Pittsburgh; Wayne Gerdes of Chicago; and Rick Reece of Greenville, S.C. -- met online in forums and discussion groups for Prius owners. Their shared interest in maximizing their gas mileage led them to devise the experiment that they will conduct this weekend, essentially comprising two steps:

Step one: Fill up the gas tank of a Prius.

Step two: Drive nonstop until the gas runs out.

The "test track" for their endurance run, which the drivers expect to last 38 to 40 hours, will be a 14-mile stretch of Route 65 running in front the Sewickley Country Inn, where the four are lodging for the weekend.

"It'll be four middle-aged men spending a hot weekend in Pittsburgh going nowhere -- and calling it fun," said team spokesman Bassage.

Bassage said the marathon drive was Kroushl's idea. So he got to pick the route.

"We all have been working on trying to maximize our fuel economy, and Dan's had the most success of any of us," Bassage said. "He's been able to get consistently up in the 80 miles-per-gallon range."

To the best of his knowledge, Bassage said, no one has tallied more than 90 miles per gallon from a full Prius tank.

They plan to drive one at a time, in four-hour shifts, beginning tonight at 6 p.m.

If they reach their 100 miles-per-gallon goal, they will have driven nearly 1,200 miles (the Prius's gas tank holds 11.9 gallons) by the time the car rolls to a stop Sunday morning.

The published EPA-estimated gas mileage for the Prius -- 60 mpg for city driving, 51 for highway, and 55 for combined -- make it one of the most gas-efficient cars on the road. But that still falls far short of the three-digit target the team has set for itself. So how do the drivers plan to gain an additional 40 to 50 miles per gallon?

In a word, gliding. Or in three words, pulse and glide -- a technique that involves releasing the gas pedal, then depressing it slightly again. Releasing it turns off the gas engine and causes the generator to recharge the battery; depressing it slightly again disengages the generator so that neither the gas engine nor the electric engine in on, allowing the car to glide.

"For the duration of this event, the gas engine will only be running a third of the time," Bassage said. "The rest of the time we'll be in glide mode."

Bassage, administrator of the office of innovation in West Virginia's Department of Environmental Protection, said that Prius enthusiasts tend to be either "enviros" like himself, whose primary interest in the vehicle arises from environmental concerns, or "techies" like his teammates, who delight in the car's mechanics.

With oil prices topping $60 per barrel, and gas pumps consistently registering $2.25 a gallon or more, their ranks may soon be swelled by "cheapies" -- people who just want to save money. Especially after President Bush acts on two bills awaiting his signature.

The first replaces a federal tax deduction for buying a hybrid with a more generous tax credit that could total as much as $3,400. The second gives states the right to open high-occupancy vehicle lanes to hybrids, even if there's only one person in the car.

The Prius is the most popular hybrid vehicle in the country. A total of 83,153 hybrids were sold in the United States last year, according to R.L. Polk & Co., a Southfield, Mich.-based firm that collects and interprets automotive data. The Toyota Prius hybrid dominated that market, with 53,761 new Prius cars registered.