ATLANTA - The next stop for NASCAR's Car of Tomorrow is the Lockheed wind tunnel in Marietta.

Engineers hope to get a better handle on the boxier car that's supposed to level the playing field in stock-car racing. Time is running short for the sport considering the car is supposed to hit the track next year and nobody, including NASCAR officials, has found a way to make it stable.

Just getting it to the wind tunnel this week has been a problem because it doesn't fit in the current fleet of transporters used by race teams.

The car is 4 inches wider and 2 inches taller than the models in the Nextel Cup Series. By making the cars bigger, NASCAR hopes to increase safety and competition by reducing how a team can massage the body.

Drivers seem to like their seat moved farther away from the left door, and they said reducing the aerodynamic dependencies might be good, but not at the expense of traction. So far, spoilers and a space-age rear wing haven't provided enough downforce at the tracks that are 1.5 mile or longer.

The development stage continues, although the car is supposed to race 16 times next year, starting with the spring race at Bristol, Tenn.

The new car will have a taller, more upright front windshield. Also, most of the key construction points are to be identical, allowing NASCAR to use lasers to complete inspections.

Many teams fear NASCAR will become like the International Race of Champions, a series where drivers compete in identically prepared cars.

"IROC complaint? I think that's good," NASCAR Chairman Brian France said. It's about "the best drivers and teams on the track. We don't want engineers winning races.

"If you want to be in a technology contest, we're not the place for you, anyway."

The boxier look is supposed to make racing more like the Craftsman Truck series, where passes are more dependent on a driver's skill than an engineer's computer.

So far, the Car of Tomorrow has been slow to come up to speed with the majority of race teams.

The next test is scheduled for May 30 and 31 at Lowe's Motor Speedway. NASCAR said it hopes to have at least eight cars on the track and as many as 12.

One team that won't be there is Robert Yates Racing. Yates has yet to start working on the Car of Tomorrow and doesn't plan to until NASCAR sets its rules.

Car owner Jack Roush said he's built and rebuilt the Car of Tomorrow a couple of times. Every time he gets one done, NASCAR makes changes.

He said he spent more than $300,000 on the car before it ever hit the track.

Rusty Jarrett/Getty Images NASCAR's Car of Tomorrow, a bigger and boxier version of today's stock car, is being developed to increase safety and competition. Only one has been built so far, but NASCAR intends to run it 16 times next season, starting in Bristol, Tenn.[CAPTION]

Today's Nextel Cup series car is 4 inches narrower and 2 inches shorter than the boxy Car of Tomorrow. Rainier Ehrhardt/associated press