Jimmie Johnson spent Sunday afternoon sitting at home, glued to the IndyCar Series TV broadcast from Las Vegas.

His mouth, he said, was wide open after seeing the replays of Dan Wheldon's fatal wreck and the massive, fiery debris field that went along with the 15-car crash.

It had a dramatic impact on Johnson, he said.

"Knowing Dan and his wife and two kids, and then I'm sitting there with my daughter running around in the backyard, I was torn up yesterday," Johnson said. "I mean, I know Dan...or knew Dan. We just stared at the TV for a long time yesterday with long faces. Just really sad."

Wheldon's wreck was another in a long line of frightening IndyCar crashes on ovals – though this one turned out to be tragic for the Indianapolis 500 winner.

Because of the ease in which IndyCars can get airborne, Johnson said it's time for that series to stop racing on oval tracks.

"I wouldn't run them on ovals," he said. "There's just no need to. Those cars are fantastic for street circuits, for road courses. The ovals at those speeds...there's very little crumple zone around the driver, it's an open cockpit and then you add open wheels – it's just creating situations to get the car off the ground at a high rate of speed. And you can't control the car when it's off the ground.

"I hate, hate, hate that this tragedy took place. But hopefully they can learn from it and make those cars safer on ovals somehow. I don't know how they can really do it. Myself, I have a lot of friends that race in that series, and I'd just rather see them on street circuits and road courses – no more ovals."

Johnson always had a dream to one day run the Indianapolis 500. But when his daughter was born last year, he promised his wife to never climb into an IndyCar.

NASCAR, Johnson said, is much safer than IndyCar racing.

"We know what the risks are (in NASCAR), and the risk factor to driving an open-wheel car is multiplied by 10," Johnson said. "Yes, that threat exists. But I feel like NASCAR has worked hard to keep speeds down, we have devices on the vehicles to keep them on the ground. We don't have those types of crashes.

"I'm not saying the perfect storm couldn't take place and we couldn't get a couple off the ground. ... But I just don't see our cars having the same issue. I don't see the chance (being) anywhere in the ballpark as those open-wheel cars."

But Johnson, whose unprecedented streak of five consecutive NASCAR Sprint Cup Series championships is in doubt after a hard crash of his own on Saturday night, had praise for the drivers who choose to run in the IndyCar Series.

"Their average was 225 (mph)? I've never been 225 mph in my life – and that's their average around an oval," he said. "They are brave men and women that drive those things."