Watch: Car flies through the air in four-car IndyCar Series crash

A four-car crash on the final lap of Sunday's IndyCar Series race at Iowa Speedway injured driver Sting Ray Robb.

Robb was injured when his car clipped the slower car of Alexander Rossi coming out of the second turn. Robb's car flipped twice, ending up on its top as it slid down the backstretch.

Kyle Kirkwood and Ed Carpenter were also involved in the crash, with Carpenter's car ending up on top of Kirkwood's.

"It was a very scary incident," Kirkwood said. "I've never seen a car fly in the air in front of me like that."

Robb gave a thumbs-up sign as he was put in an ambulance to be taken to the infield care centre. He was awake, alert, and in good condition, IndyCar Series officials said. He was flown to Mercy Medical Center in Des Moines for further evaluation.

AJ Foyt Racing, Robb's team, said in a statement Robb was taken to the hospital as a further precaution and was taken by helicopter due to the post-race traffic and the distance to the hospital.

"Sting Ray is up, alert, and in good spirits," the statement said.

Robb, 22, is in his second full season in the IndyCar Series.

Rossi said he had slowed on the track in the closing laps because of a fuel issue.

"It was the last, kind of, four laps," Rossi said. "We were out of fuel, I don't know why. I don't know why I got hit."

"Alex was off pace for a couple of laps," Carpenter said. "I saw that, my spotter told me, so I figured he had a fuel problem or some problem. Stinger had to see he was going slower, I think he misjudged the closing rate a little bit."

Kirkwood said he got "claustrophobic" with Carpenter's car on top of him.

"I obviously wanted to get out of the car as quickly as possible," Kirkwood said. "When you have no control of your ability to get out of the car, you become claustrophobic extremely quick. It's easy to find yourself in a panic when it's this hot out and you've just done an entire race, and we were having problems with the cool suit. It's safe to say I was extremely hot and ready to get out of the car."

Team Penske’s Kiwi Scott McLaughlin, the winner of race one, finished third after starting on pole.