Drivers are prohibited from exiting their cars barring "extenuating circumstances," NASCAR vice president Robin Pemberton announced Friday.

"It's safety first right now," Pemberton said.

"At no time should a driver approach a moving vehicle."

A rule change to take effect immediately was pushed through by NASCAR in the wake of the dirt track race death in which Sprint Cup driver Tony Stewart struck and killed 20-year-old Kevin Ward Jr.

"We're all going to think twice," said Kyle Larson, the 22-year old driver from California who came up racing on dirt tracks. "If we're upset, we're going to think twice before getting out of the car."

Ward's funeral was Thursday in New York.

"It's not just about NASCAR. It's about all of motorsports," Pemberton said.

Stewart did not race last week at Watkins Glen and announced he would sit out again Sunday at Michigan. Stewart-Haas Racing is unsure when Stewart might return. The team said Friday that Jeff Burton was promised only this week's race but stated that the Chase playoff standings were not even a minor priority for Stewart.

Stewart isn't at Michigan International Speedway, and his absence is being felt.

"This decision was Tony's," said Brett Frood, executive vice president of Stewart Haas Racing. "An emotional week for him. He's grieving. Made the decision he's not ready to get in the racecar and will take it week by week. It will be up to Tony when he's ready to get back in the car."

Defending NASCAR champion Jimmie Johnson said Friday that short tracks should soon adopt a policy for spotters in the name of increasing safety. Even the notably reserved Johnson, who said he has been unable to reach Stewart, recalled an incident during his rookie season when his temper got the best of him and he got out of his car to offer a one-finger salute to Robby Gordon at Bristol.

Johnson said he believes the fatal crash was a "complete accident," but allowed that hearing from Stewart is likely the only way to set others at ease.

Until then, some will play independent jury, but the majority of NASCAR drivers are not playing judge.

"It's not right for me to discuss what happened; it's a tragedy," said Carl Edwards. "I've been around racing my whole life ... I don't know what happened."