Following the on-track death of Kevin Ward Jr. last weekend, NASCAR announced the implementation of a new rule on Friday that requires drivers who crash to stay inside their cars until track officials tell them they can get out.

"We're just formalizing rules that have already been there," Robin Pemberton, NASCAR's vice president of competition told reporters. "It's safety first right now." NASCAR warns drivers before every race to stay in their cars at all times, but it has always been an informal "understanding." Now it will be an actual written regulation, with the potential for penalties for those who violate it. 

Pemberton confirmed that the new rule comes "on the heels" of Ward's death.

Last Saturday, the 20-year-old Ward died after being run over by Tony Stewart's car during a sprint car race at the Canandaigua Motorsports Park in upstate New York. After colliding with Stewart and crashing into a wall, Ward climbed out of his vehicle and walked towards the center of the track, where he was struck by Stewart's oncoming car on his next lap.

Yesterday, Stewart, who hasn't competed since the August 9 incident, withdrew from this Sunday's NASCAR race at Michigan International Speedway. The investigation into the death is still ongoing.

"You have to recognize when you get a reminder or a tap on the shoulder of something that may need to be addressed and this is one of those times," Pemberton said. He also said the details of the rule will be passed out to teams this afternoon, and added that it would be implemented "according to each individual situation."