NASCAR NEXTEL Cup Series point leader Tony Stewart and championship contender Greg Biffle each crashed for the second time in less than 30 hours Wednesday at Charlotte Motor Speedway as five teams made final preparations for the Oct. 15 UAW-GM Quality 500.

Neither Stewart nor Biffle were injured and both were able to drive their heavily damaged cars back to the garage area.

Bouncing back from his hard crash Tuesday afternoon, Stewart was consistently quick throughout the testing session and recorded the fastest lap of the evening just moments before a cut right-front tire sent the No. 20 Joe Gibbs Racing Chevrolet into the Turn 3 SAFER Barrier.

"I had just run a 28.88," Stewart said. "I'm thinking 'this is pretty good,' and then I get to Turn 3 and I'm thinking 'this isn't good.'"

Stewart's lap of 28.887 seconds, 186.935 mph, was the fastest of the two-day session but Stewart was still befuddled by the track's levigated surface.

"It's better, but I only ran three laps yesterday so I'm not really able to make a comparison," he said. "All the rubber that's being put down is helping. But what scares me is that all the rubber is being put down in one groove, and I'm not sure we are going to be able to pass."

Biffle's day ended extremely early as the Vancouver, Wash., native crashed hard in Turn 2 less than an hour after the green flag was unfurled. Out of race cars, the No. 16 Roush Racing team loaded up and headed home.

Opting to only test on Wednesday, Kyle Busch said track conditions were improving as the session progressed.

"It's getting better the more people run on it. I started off today really, really tight which is probably a good thing," Busch said about his No. 5 Hendrick Motorsports Chevrolet. "The set-up we have for this place is dynamite. I'd like to be a little bit better but everybody always says that. I would like to be beating everybody by about two-tenths and that's what we're working toward."

Busch was second fastest on the unofficial stopwatches at 185.452 mph while older brother Kurt was next at 184.237 mph in the No. 97 Roush Racing Ford.

Scott Wimmer was clocked at 183.511 mph in the No. 22 Bill Davis Racing Dodge and Biffle posted a lap at 182.414 before his accident.

Next up on the testing docket is two days of runs for the NASCAR Busch Series teams as they prepare for the Dollar General 300 on Friday night, Oct. 14. More than a dozen drivers, including NEXTEL Cup stars Tony Stewart and Ryan Newman, are among those scheduled to test Tuesday and Wednesday. Cars will be on the track from 3 p.m. to 6 p.m. and 7 p.m. to 10 p.m.

Fans can watch the action from the frontstretch grandstand free of charge and should enter through Gate 5A which is located next to the ticket office in Smith Tower.

Tickets for all events during UAW-GM Quality 500 weekend, including round five of the 10-race Chase for the NASCAR NEXTEL Cup, can be purchased by calling 1-800-455-FANS or online here.

The unofficial speeds:
Showing driver, car number and speed:
1. Tony Stewart, 20, 186.935
2. Kyle Busch, 5, 185.452
3. Kurt Busch, 97, 184.237
4. Scott Wimmer, 22, 183.511
5. Greg Biffle, 16, 182.414.