Volatile NEXTEL Cup driver Tony Stewart has been fined $50,000, penalised 25 points and placed on probation until 18 August following his post-race altercation with fellow driver Brian Vickers at Infineon Raceway last Sunday.

The point penalty drops Stewart one spot in the series standings, to sixth place, while Joe Gibbs, the owner of the #20 Chevrolet driven by Stewart, has been penalised 25 points. Stewart was found in violation of Section 12-4-A of the Cup Series rule book - actions detrimental to stock car racing and involved in altercation with another competitor.

"The action we've taken speaks for itself," NASCAR president Mike Helton insisted, "Tony Stewart is well aware of what is expected of him going forward."

Stewart has admitted that he must do more to protect the sport following the garage area incident with Cup Series rookie Vickers after last weekend's road race in California.

"I understand and accept NASCAR's penalty," he said in a team statement, "With NASCAR's continued growth and its rise in mainstream popularity, I realise the rules have become stricter than they were in the past. And, after meeting with [NASCAR chairman and CEO] Brian France, I know it's my job to live within those rules. I'm putting this incident behind me and I plan no further comments. I'm going to focus on Daytona and the remaining races before the final ten-race run for the championship."

Gibbs also felt moved to offer an apology on his driver's behalf.

"On behalf of everyone at Joe Gibbs Racing, we agree with NASCAR that Tony Stewart's actions after the Sonoma race were unacceptable," he said, "We understand the reason for the penalties handed down by NASCAR and we accept their decision."

In addition to the penalties handed out to Stewart and the Gibbs team, Shane Wilson, crew chief for the #77 Dodge driven by Brendan Gaughan, was fined $10,000 and placed on probation until 31 December, after being found in violation of Section 12-4-A and 12-4-Q, after an unapproved fuel cell container modification was discovered.