Auto Racing | 50-year-old Mark Martin wins Southern 500

DARLINGTON, S.C. — Mark Martin won for the second time in the last four NASCAR Sprint Cup Series races, outlasting Jimmie Johnson in a wreck-filled Southern 500 at Darlington Raceway on Saturday night.

There were a track-record 17 cautions.

"Once we got out front, man, it was just easy," said the 50-year-old Martin, who led the final 46 laps. "The car was awesome."

Martin's other Darlington victory at NASCAR's top level was in the 1993 Southern 500.

Martin ended a 97-race winless streak last month in Arizona and has 37 career Cup victories.

"Hey, man, I'm loving it," he said of his recent success.

Greg Biffle of Vancouver, Wash., finished eighth after hitting a wall; he led a race-high 117 laps. Kasey Kahne of Enumclaw was 23rd.

Mayfield fails

random drug test

DARLINGTON, S.C. — Jeremy Mayfield was suspended indefinitely by NASCAR for failing a random drug test, becoming the first driver to violate a toughened policy that went into effect this season.

Mayfield, 39, tested positive for a banned substance last weekend in Richmond, Va.

"In my case, I believe that the combination of a prescribed medicine and an over-the-counter medicine reacted together and resulted in a positive drug test," Mayfield said in a statement. "My doctor and I are working with both Dr. [David] Black and NASCAR to resolve this matter."

Black is the CEO of Aegis Sciences in Nashville, Tenn., which runs NASCAR's testing program. The suspension can't be appealed.

NASCAR spokesman Jim Hunter would not reveal what banned substance Mayfield used, but Hunter said it was not an alcohol-related offense.

"There is no place for substance abuse in our sport," Hunter said.

Mayfield, who this season is driving a car he owns, failed to qualify for the Southern 500.

Castroneves earns

3rd Indy 500 pole

INDIANAPOLIS — Less than a month after being acquitted of charges of tax evasion, Helio Castroneves was right where he wanted to be — on the pole for the May 24 Indianapolis 500.

On a cool, windy day, the Brazilian driver took a big gamble, voiding a fast qualifying effort from earlier in the day and knocking Penske Racing teammate Ryan Briscoe off the pole.

Castroneves' four-lap average of 224.864 mph on the 2.5-mile oval came with less than two hours remaining in the six-hour opening round of time trials.

Castroneves previously won poles in 2003 and 2007.

Note

• Series leader Jenson Button won the pole for today's Formula One Spanish Grand Prix in Barcelona.