INDIANAPOLIS — IndyCar will require all cars attempting to qualify for the Indianapolis 500 to use race trim and normal boost levels Sunday after another frightening crash in practice.

Series CEO Mark Miles also said drivers will not be awarded points based on their starting position for the May 24 race.

The moves come after Ed Carpenter’s car hit the wall in the second turn, turned backward and flipped over. It’s the third time this week a car has been unable to keep all four wheels on the track’s 2.5-mile asphalt surface after getting turned around.

Carpenter, like the other two drivers, was cleared and released from the infield medical centre without any serious injuries.

All three cars that have gone airborne were Chevrolets, which like Honda, is debuting a new aero kit at the first oval race of the season.

But the rules changes will apply to every car trying to make the 33-car starting grid.

“When we’re talking about an event here, we’re talking about safety,” said Derrick Walker, the series’ president of competition and operations. “It’s not about a manufacturer, one versus the other. It’s about how can we grab ahold of this situation and reduce the speed in the interest of safety and safety is going to be our guiding light.”

Carpenter’s crash sent everyone into scramble mode.

Speedway president Doug Boles apologized to fans over the public address for the delay in qualifying as track workers continued to try and fix the catch-fence that was damaged by the car.

Qualifying was scheduled to begin at 10 a.m. ET, but after series officials met with team owners in Gasoline Alley, organizers pushed the start time back to 3:15 p.m. and eliminated the nine-car pole shootout.

Drivers had been given an extra boost of about 50 horsepower for qualifying weekend, but there were no crashes with the extra power Friday or Saturday.

Organizers also revised Sunday’s qualifying schedule again.

Each car now has one qualifying attempt with the top 30 average speeds being locked into those starting spots. If weather permits, a 45-minute qualifying session will determine the final three starting spots for next Sunday’s race and which of the 34 cars will go home.

“All I can say is I’m sorry to all the fans,” Honda driver Graham Rahal posted on Twitter. “This is unreal.”

Chevrolet has dominated the early part of the season, winning all five poles and four of the first five races.

After the meeting, Jim Campbell, the U.S. vice-president for Chevy’s performance vehicles and motorsports issued a statement.

“Chevrolet met with IndyCar this morning and the decision was made to run race-level aerodynamics and engine boost during qualifying in an effort to reduce speeds and increase downforce,” he said. “We continue to review all available data from the crashes. Safety is our priority.”

Many are asking whether enough testing was done before coming to Indy.

Series spokesman Mike Kitchel said earlier this week that extensive testing was conducted on ovals during the off-season, but no other track on the circuit is quite like Indianapolis, which produces the highest speeds with long straightaways and four distinctly different corners.

Walker insisted the problems they have seen can be fixed, though nobody in the series was ready to push speeds up at the expense of safety.

“The ultimate test is when you get on the racetrack and that, somewhat, is where we are now,” Walker said. “We’ve got a situation and we’re trying to learn as quickly as we can while, at the same time, put on a competitive race with basically two different configurations.”

Earlier this week, three-time Indy winner Helio Castroneves went airborne after hitting the first turn wall and getting spun around on Wednesday.

On Thursday, American Josef Newgarden also went airborne after hitting the first turn wall and going backward on the track. Newgarden’s car skidded to a stop on its side.

Both were back in the cockpit less than 24 hours later.

Carpenter spun into the wall, and when it got turned around, flipped over and skidded down the track on its side with sparks flying.

Walker said Newgarden’s crash was the result of air pressure being lost in the tire, and Castroneves was caused by an aero balance that went too far, and Carpenter’s was simply an accident.

Carpenter is trying to become the first driver to win three consecutive poles at Indianapolis.

“It caught me by surprise,” he said. “I wasn’t expecting to swap ends. The car was actually feeling pretty good, better than it did yesterday. Things are a little unpredictable right now.”

But concerns were raised even before the Indianapolis native slammed hard into the wall Sunday morning, bringing an early end to the scheduled practice.

Newgarden and Carpenter are teammates with CFH Racing. Carpenter said the team was preparing the road-course car for qualifications and that it would be ready when qualifying is scheduled to begin at 3:15 p.m.

After Saturday’s qualifying round was rained out, organizers revised Sunday’s schedule to give drivers two short practice sessions in the morning.

Each driver was supposed to line up at 10 a.m. and make one qualifying attempt.

But on a muggy, overcast morning with the threat of rain looming yet again, Carpenter’s crash changed the schedule — and how qualifications will be handled.

“Let’s get thru the next week,” team owner Chip Ganassi wrote on Twitter. “I don’t sense much appetite at the moment for lap records from teams, drivers, owners!”

Michael Marot, The Associated Press