A terrible accident during a auto race in the United States: Many cars collided

A terrible accident occurred during the "IndyCar" championship race held at the oval autodrome in the state of Iowa, USA. According to the report, Will Power, who competed in the Penske team, won the race, but when he crossed the finish line, four cars behind him collided with each other.
In the video published on the social network accounts of "IndyCar" the images of the incident from all angles are shown.
On the last lap of the race Alexander Rossi ran low on fuel and slowed dramatically. Sting Ray Robb closed on Rossi’s car quickly, hitting its left rear. The contact sent Robb’s Chevrolet into the air and then into a tumble on the track surface. The car landed on its aeroscreen, and Robb was placed on a stretcher after being removed by safety workers. He was taken to a nearby hospital but was listed in good condition. Ed Carpenter and Kyle Kirkwood also were involved in the crash. Carpenter’s car came to a stop on top of Kirkwood’s, with Carpenter’s left rear tire sitting on Kirkwood’s aeroscreen. After a tense minute or so, workers helped Kirkwood exit his car.
“I’m not sure exactly what happened with the fuel load, but we had to go into a pretty crazy save mode there at the end,” Rossi said. “I think we were going to get there, but unfortunately there was an incident where I was beginning to lose fuel out of Turn 2, and it ended our day.”
All participants who were injured in the accident were given immediate medical assistance. Three of them were released after examination at the medical station of the autodrome, and one more was conscious and his condition was not dangerous. However, he was admitted to a local hospital for further examination.