INDIANAPOLIS -- Questions are raised any time a racing driver dies. But when it's a high-profile star like two-time Indianapolis 500 winner Dan Wheldon, who perished in a graphically violent 15-car accident Sunday at Las Vegas Motor Speedway, the scrutiny is even more intense.
"This is the big accident everyone always hoped wouldn't occur," said ABC analyst (and former Indy car racer) Eddie Cheever.
Pundits from Jimmie Johnson to Jody Scheckter called for the IZOD IndyCar Series to drop oval racing altogether because they believe it is simply too dangerous for 220-mph open-wheel cars, though Johnson later clarified his position, saying he was referring to high-banked ovals.
That's an easy conclusion to reach after watching replays of the Las Vegas crash, which sent four of the 15 cars airborne. But despite the severity of the incident, only two other drivers suffered relatively minor injuries; Pippa Mann sustained burns to her right hand that will require surgery, and JR Hildebrand suffered a severely bruised sternum.
Like every form of motorsport, Indy car racing's safety record has improved dramatically over the course of time. Wheldon was the eighth Indy car driver to die in the past 20 years; since 1991, eight drivers were also killed in NASCAR competition, while Formula One's last two fatalities occurred in 1994.
Six of the eight driver fatalities in Indy cars occurred at oval tracks, while seven of the NASCAR deaths also took place at oval venues.
There hasn't been a death in major stock car racing since Dale Earnhardt was killed on the last lap of the 2001 Daytona 500, an event that spurred the development of what became known as NASCAR's "Car of Tomorrow." By contrast, the current generation of Indy car has been involved in three fatal accidents since late 2003.
"What happened to Dan is a huge tragedy for INDYCAR but I hope that out of this tragedy comes some good in terms of improving more in safety, like when Greg Moore [killed in a 1999 Indy car crash at California Speedway] and Dale Earnhardt died," said Paul Tracy, the winner of 31 Indy car races and one of the drivers involved in Sunday's crash. "The innovations that come out from this in terms of improving driver safety need to be kicked up another notch. We hope that is what will happen."
INDYCAR said Tuesday it has launched a full investigation of the Las Vegas crash.
"The safety of our drivers, their crews, IndyCar staff, racetrack staff and spectators is always our paramount concern," INDYCAR announced in a statement. "We hope to have preliminary findings to report within the next several weeks. In the meantime, it would be inappropriate to comment further until the investigative team has had the opportunity to conclude its work."
Here are some of the factors that will likely be investigated:
Indy cars circulated Las Vegas Motor Speedway at about 225 mph, or 10-15 mph faster than most other similar tracks. Those high speeds were the result of LVMS' 20-degree banking -- second steepest among the 1.5-mile tracks the IndyCar Series races on -- and an unusually smooth racing surface.
But one of the fastest Indy car drivers in history says that speed itself is not the problem. Mauricio Gugelmin, who held the Indy car qualifying speed record from 1997-2000 and still holds the unofficial record for the fastest lap ever achieved by an Indy car (242.333 mph at California Speedway in 1997), said he believes the format of 1.5-mile tracks such as Las Vegas is simply not suited to ultra-fast open-wheel cars.
"Like an airplane accident, a racing crash usually doesn't happen unless there are a number of factors involved," Gugelmin said. "I had an enormous wreck at Texas Motor Speedway, and the reason it was so big is that I crashed at a place that our cars were not made to run."
Gugelmin said he believes that outright speed was not a factor in the Las Vegas crash. Instead, he cited the lack of a difference in speed between the cars that created pack racing that put the cars too close together to be safe.
"I remember when we ran the 240 mph laps at California Speedway people were saying, 'You're crazy to drive at that speed!'
"But we had a car that was designed to run at those speeds that was well balanced with small wings.
"The racing maybe wasn't as close as some people would like to see. But we still had some very good racing and I think people may have forgotten a little bit about what racing is all about. Now in every series all they talk about is passing and side-by-side and in America it's even worse. They want to see that last-lap dash to the line, but when you get highly competitive people that close together in open-wheel cars, you're going to run into trouble."
Dario Franchitti, who clinched his fourth IndyCar Series championship in the last five years, shared a similar opinion.
"I've raced here [LVMS] in a stock car and I said before we even tested the Indy car here that this was not a suitable track for us, and we've seen that today," Franchitti said during the red flag period after the crash on Sunday. "You can't get away from anybody. There's no way to differentiate yourself as a car or a driver. People get frustrated and go four-wide and you saw what happened."
2. Oval tracks, specifically 1.5-mile high-banked speedways
Las Vegas Motor Speedway was built to the most modern safety standards for oval tracks and is one of the few ovals that features the SAFER (Steel and Foam Energy Reduction) Barrier around the entire track.
"It's a world-class facility, and it's no different to any other racing track around the world," said Tracy. "It has the same type of wall and fencing system as any other racetrack. But you have a lot of cars racing in close quarters."
The steep banking that is a feature of tracks such as Las Vegas and Texas is what makes the Indy cars so fast. Tony Kanaan's pole speed of 222.078 mph was 34 mph faster than the NASCAR track record set by Matt Kenseth earlier this year.
To achieve those speeds, Indy cars run as little downforce as possible to reduce drag, yet the drivers are still able to keep their foot to the floor, 100 percent on the throttle all the way around -- even when running two or three wide.
"Racing on that sort of track is too fast and too close," said IndyCar Series championship runner-up Will Power, who was briefly hospitalized with back pain after his car got airborne in the Las Vegas crash.
Speaking to Triple M radio in his native country of Australia, Power said: "When you are averaging 370 kilometers per hour [230 mph] and you are inches apart, it was a recipe for disaster in my mind. I had voiced my opinion over the last few years that when we run on these mile-and-a-half superspeedways with high banking, it creates this pack racing. It takes one little mistake from someone and the result is never good. It's always a hard hit into a wall; it's always a big crash."
3. The catch fence
Oval track safety took an enormous leap forward with the introduction of the SAFER barrier, inspired by IRL founder Tony George and developed by the University of Nebraska. The cushioned wall has prevented innumerable spine and head injuries and likely saved quite a few lives in its NASCAR and INDYCAR applications. The problem now is the catch fence; once a car rises above the wall, the fence is waiting to literally shred a car to pieces. The fence is there to prevent cars or debris from going into the grandstands and protect the spectators, but on the rare occasions when a car does get up into the fence, it can have devastating consequences.
"My concern now is that the fencing is the problem with motor sport," said Tracy. "You see stock cars flying and get in the air and go backwards, and when they get into the fencing the cars get ripped apart. It's very much the same for Indy cars. I think the cars right now are pretty safe but the next thing needs to be done to the fencing."
"I've been running on these ovals for a couple of years now and your worst nightmare is to end up airborne and heading toward the catch fence," added Power. "The catch fence just destroys the car. A lot of guys have had their legs destroyed and there's been some pretty big injuries. Unfortunately, Dan ended up on the catch fence and that's what got him."
But how do you replace it? Some, including Tracy and NASCAR champion Johnson, have suggested a ballistic-strength plexiglass wall like at a hockey rink. But it would have to be 20 feet high and be capable of stopping a 1,500-pound Indy car (or a 3,500-pound stock car) at speeds of up to 220 mph.
4. The larger-than-usual field
This was the last race for the current generation of Indy cars; with new cars and engines being introduced for 2012, every team's inventory of chassis was set to be rendered essentially worthless after the Las Vegas finale, so some teams elected to field extra cars. Most Indy car races this year, with the exception of the Indianapolis 500 (where the traditional 33 cars started on the 2.5-mile track), featured 24 to 26 cars. A provision in the INDYCAR rulebook allows the series to cap the field at 28 cars when pit space is at a premium, but that was not an issue at LVMS.
At Las Vegas, the field was broken into two groups in practice to avoid traffic congestion and Sunday was the first time that all 34 were on the track at the same time.
"We practiced no more than 15 to 16 at a time and now we've got 34 out there," said driver Alex Lloyd. "I knew there was going to be some trouble."
Canadian James Hinchcliffe clinched IndyCar's rookie of the year award at Las Vegas and barely missed getting involved in the race-ending accident. In fact, when Wade Cunningham's front wing touched Hinchcliffe's right-rear tire, it sent Cunningham into the spin that triggered the multicar wreck.
"At the end of the day, the series isn't stupid," Hinchcliffe said. "I'm sure some people expressed their concerns to Brian [Barnhart, INDYCAR competition director], but they've been around racing for a long time and they know that 34 cars on a 1.5-mile track is something that has never been done.
"There's a few people who are doing their first race, or their first race in a long time, and at this track in particular, there's no margin for error," he added. "There's zero time to react, whereas at a place like Kentucky Speedway, where the cars move around a bit more, there's not as much threat so you give each other more room. We're all competitive people, and that's what leads to these situations where if one thing goes wrong it has very bad consequences."
Once the decision was made to allow such a large field, there is little that series officials could have done to keep the drivers in check.
"You can have good stewards who do a good job of controlling the drivers and making sure they respect each other," said Gugelmin. "But when the old red mist drops, you're going to have problems."
5. The safety of the 2003 Dallara Indy cars
One of the saddest aspects of the Las Vegas tragedy is that it was the last race for the chassis and engine formula that the Indy Racing League (now INDYCAR) debuted in 1997. All of the cars in Sunday's race featured a chassis constructed by Italian manufacturer Dallara that was introduced in 2003. As such, it did not feature safety advances that were pioneered in much of the last decade that were set to be implemented in the 2012 Dallara design that Wheldon spent the last two months testing and developing.
The 2012 car has wider sidepods that extend to the outer edge of the rear tires in an effort to keep cars from locking wheels. It also features crash-proof structures behind the rear wheels that are intended to prevent cars from launching up into the air like what occurred at Las Vegas.
Dallara announced Tuesday that the 2012 car will be named in honor of the work Wheldon carried out in its development.
"Dan lives in the memory of everybody at Dallara," company president and founder Gianpaolo Dallara said. "He has been a true champion and we will honor his memory for the years to come by dedicating the Dallara IndyCar 2012 in his name. He deserves that."
6. What next?
The investigation into the fatal 15-car accident at Las Vegas Motor Speedway will stretch into weeks, if not months.
INDYCAR canceled a planned test of the 2012 car scheduled for Wednesday and Thursday at LVMS and the series' plans for continuing the test program are unclear at this point.
Franchitti was scheduled to drive Honda's 2012 test car this week. "I appreciate @IndyCar canceling my husband's test at Las Vegas track," his wife, Ashley Judd, said in a Twitter post. "The new car needs development - but not now, and never again there."
Newly crowned series champion Franchitti has maintained a low profile this week, but several other IndyCar drivers went back to work by flying to Australia to participate in the V-8 Supercar event this weekend at Surfers Paradise. The trophy for the best-placed international driver in the Armor All Gold Coast 600 has been renamed the Dan Wheldon Trophy.
Wheldon had been one of six IndyCar drivers scheduled to compete in Australia. Power and Tony Kanaan have chosen to withdraw from the event, while Alex Tagliani, Helio Castroneves and Ryan Briscoe will continue in the race as planned.
"With what happened over the weekend in Las Vegas, I think it was good for [wife] Bronte to get away from the atmosphere down there and for me personally it's kind of the same," said Tagliani. "As soon as you get back into a car and you're in racing mode, you don't think that much and I think in this particular situation the less you think the better it is."
A public memorial for Wheldon has been scheduled for Sunday at 4 p.m. local time at Conseco Fieldhouse in Indianapolis.
John Oreovicz covers open-wheel racing for ESPN.com.