(CNN) -- IndyCar said it has launched an investigation into the 15-vehicle wreck that claimed the life of driver Dan Wheldon and expects to have preliminary findings within weeks.





The organization said Wednesday individual members of various motorsports bodies will help it determine factors involved in the fiery incident Sunday at the Las Vegas Indy 300.





IndyCar said it had incorrectly stated Tuesday that the Automobile Competition Committee of the United States (ACCUS) and the Federation Internationale de l'Automobile (FIA), the national and international governing organizations, were formally involved in the investigation.





The violent crash raised fresh questions about safety, both in motor sports, generally, and at the Las Vegas track, specifically.





Wheldon, a two-time Indianapolis 500 winner, had been pressing efforts to address such concerns.





In an early October story posted on IndyCar.com, the racing series' official website, IndyCar Vice President Will Phillips singled out the 33-year-old driver, his team and Italian manufacturer Dallara for their efforts to fine-tune a safer car model for the 2012 season. Weeks ago, Wheldon was behind the wheel of a new prototype car for the IZOD IndyCar racing series -- one meant to make his sport safer.





"He's focused on what's been needed from him to provide for the feedback to Dallara and be consistent and concise," Phillips said then of Wheldon. "You couldn't have asked for more."





Had he won Sunday's race, the Englishman with the ready smile and engaging manner would have earned a $5 million payout. Instead, he was near the back of the 34-car field when he got mixed up in a crash that featured numerous cars spinning out of control and bursting into flames, spewing smoke and debris.





IndyCar on Tuesday said it was saddened by Wheldon's death.





"The safety of our drivers, their crews, IndyCar staff, racetrack staff and spectators is always our paramount concern," IndyCar said in a statement, declining to comment further on the probe.





A public memorial service for Wheldon will be held on Sunday at the Conseco Fieldhouse in downtown Indianapolis, IndyCar said. A fund has been established to help provide for his family. Wheldon was survived by his wife, Susie, and two young sons.





Two drivers seriously injured in the wreck -- J.R. Hildebrand and Pippa Mann -- were released Monday from the University Medical Center in Las Vegas, said IndyCar.





Wheldon's death was the first for the IndyCar circuit since March 2006, when driver Paul Dana was killed in a two-car crash while warming up for the season-opening race at Homestead-Miami Speedway. One of the most famous racing deaths was that of the elder Dale Earnhardt in NASCAR's 2001 Daytona 500.





Sports Illustrated senior writer Jon Wertheim said Monday that the sheer speed of race cars, and the minimal distance separating them, means danger lurks around every turn and on every straightaway. Wheldon, for example, was bunched with several other vehicles cruising at about 220 mph when Sunday's crash occurred.





"The fact of the matter is, you're dealing with very, very fast automobiles. They're not heavy cars," Wertheim said. "There is, unfortunately, an assumption of risk when you get into one of those race cars."





Beyond questions about racing's safety generally, the condition of the Las Vegas Motor Speedway -- and whether or not it was too fast and too crammed with vehicles -- was the subject of intense questioning in the hours after Wheldon's death.





Driver Dario Franchitti told ABC News that the track offered "nowhere to get away from anybody."





"This is not a suitable track, and we've seen it today," he said.





The loop in Las Vegas is 1.5 miles, one mile shorter than the iconic Indianapolis Motor Speedway. At the same time, it is wider than many others -- such that more cars can run alongside, and potentially collide with, one another.





CNN's Greg Botelho and David Close contributed to this report.
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Sunday Sunday the track offered "nowhere to get away from anybody." at the Las Vegas Indy 300. Dario Franchitti Dan Wheldon that the track offered "nowhere to get away from anybody."
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