Kyle Busch has been parked by NASCAR for the weekend as punishment for aggressive driving and causing an on-track collision with Ron Hornaday under a caution during the Camping World Truck Series race on Friday night.

Busch will not be allowed to take part in either the AAA Texas 500 Sprint Cup race or the O'Reilly Auto Parts Challenge Nationwide Series race, after having also been ordered to the garage during the WinStar World Casino 350k Truck Series event following the incident on lap 15 of the evening race.

It started the previous lap when Hornaday got loose while fighting Busch for position behind slow traffic. Hornaday got loose and moved up the track, sending both trucks against the wall. During the ensuing caution, Busch retaliated by accelerating into the back of the #33 and turning Hornaday into the wall in a hard, head-on impact that wrecked both vehicles. (See earlier story for more details.)

Busch may face further sanctions next week when NASCAR meets and reviews the race weekend as a whole. He could face fines, points deductions - or further race suspensions. A probation period would appear to be an inevitability.

Denny Hamlin will take over Busch's Nationwide car for the remainder of the weekend, while Michael McDowell will be in the Joe Gibbs Racing #18 Cup car. McDowell (who drives for JGR in the Nationwide Series) originally qualified in the #66 car, which is now expected to be handed to Josh Wise for the Sunday afternoon race.

It's the first time that NASCAR have thrown a driver out of races since Robby Gordon, after he disobeyed NASCAR orders at a Nationwide event in Montreal in 2007. A penalty affecting all three national series has never been applied.

In a season that has been dominated by NASCAR's new 'Boys, Have At It' hands-off approach, the sudden intervention by NASCAR over an on-track incident is a major shock - especially given that it means parking a Chase contender at a crucial point in the championship.

"The responsibility that, over the past two or three seasons, we've given back to the drivers, came with a very clear understanding that there could be a line that got crossed," explained NASCAR President Mike Helton on Saturday morning, after informing the media about Busch's suspension. "As annoying as the comments I've made personally in the past - about 'We'll know it when we see it' - might have been, we saw it last night.

"I think the garage areas - the drivers, the team owners, the crew members - understand the difference between being responsible and crossing the line," he added. "I honestly believe they understand the difference, but we'll have to wait and see how the opinions react to this."

Helton added that Busch's previous catalogue of incidents this season did not bear significantly upon the decision to park him for the Texas weekend, and nor did the fact that Hornaday was racing for the Truck Series championship.

"Today is the most severe reaction, but we felt like the circumstances came together to warrant the reaction we're talking about this morning," emphasised Helton. "It's not an easy step to take. It's not something we enjoy doing. It's not an action we would want to do. But we do take our responsibility to maintain the garage areas and the unfolding of the events very seriously."

There was no comment following the suspension from Busch, who will likely remain at the racetrack for the weekend despite being suspended from racing.

After the clash with Hornaday on Friday night, Busch rejected the blame for the initial incident and had commented that "the fact of the matter is you can't place all the blame on one person. There was two people that got into it to begin with, and there was two people that ended it."

Hornaday had been furious and demanded that NASCAR park Busch for the weekend - or else he would take action of his own. "If NASCAR doesn't do it, I'm going to buy Tommy Baldwin's ride and that guy will never finish another [Cup] race," he'd thundered after his truncated race.

Busch was informed of the decision at the NASCAR hauler in the Texas Motor Speedway paddock just prior to the scheduled start of Cup practice. He was accompanied to the meeting by his JGR team owner Joe Gibbs and team president JD Gibbs.

Even though Busch's actions took place in the Truck Series where he drives for his own team - Kyle Busch Motorsports - rather than JGR, Joe Gibbs said that he took full responsibility for the situation. "When you own something ... you're responsible," he said.

"We met this morning with NASCAR and they explained their situaton and decision, and after that sometimes in life you have to deal with real tough things," he continued, adding that he respected and supported NASCAR's decision over the matter. "They always do a great job to manage the sport," he said. "I have great faith in the decisions they make ... I think this sport is where it is because of NASCAR and the way they handle things."

Gibbs now urgently needs to crisis-manage the situation. After a season of troubles for Busch - which have included run-ins with Kevin Harvick on the track and Richard Childress off it, not to mention Busch's own run-in with the police over a 128mph speeding incident in a sports car on local roads - JGR's backers such as the primary sponsors M&Ms are getting increasingly unhappy with the bad publicity that Busch is bringing them.

"We're certainly going to try and work our way through this one and do the right thing and handle it the right way," Gibbs said, explaining that the situation had come up so fast that he had not yet had a chance to discuss what had happened with the team's partners and sponsors. "This was a tough situation for us."