Why don't more F1 drivers do the Indy 500?

On the surface, it's such a simple question: Why don't more Formula 1 drivers race in the Indianapolis 500?

The current divide between F1 and Indy feels every bit a big as the Atlantic Ocean that separates them geographically, and certainly larger than whatever gulf might exist between F1 and the Le Mans 24 Hours.

It wasn't always this way. The 500 was part of the F1 World Championship between 1950 and 1960, and even after the race fell off the F1 calendar it was a popular stop for F1 regulars: Jim Clark and Graham Hill were both in the middle of Formula 1 campaigns when they won in 1965 and '66 respectively.

By the 1980s, US-based foreigners were commonplace, but there were still interlopers: Nelson Piquet in 1992 and '93, Nigel Mansell in '93 and '94, Johnny Herbert in 2002.

But since then, the flow has slowed to a trickle. And like many simple questions that involve different cultures and ideologies, it can quickly become surprisingly loaded. American open-wheel racing has been to hell and back over the past 20 years, but the one thing it has always been able to claim - with complete justification - is that it still has the biggest motor race in the world.

American racing's journey through the split, reunification, and the current era of recovery has made it all the more protective of Indy's status. To some, the question of 'Why don't more F1 drivers race in the Indy 500' potentially carries a silent prefix: 'If your race is so good ...'.

Graham Hill is the only driver to have won Monaco, Le Mans and Indy © LAT

The question is never framed in any other way. The traditional motorsport Triple Crown is the Monaco Grand Prix, Indy and Le Mans. Hill is the only driver to have won all three; Juan Pablo Montoya is the only active driver to have won two of them. But it's rare that anyone asks why more IndyCar drivers don't make the trip to central France in June.

"I think you have to put a bit of the blame on Formula 1," says Chip Ganassi, whose team has won Indy four times, and who has Scott Dixon starting on pole on Sunday.

"You have a situation where those guys can't pick up and leave the way they used to be able to do in the 1960s, with the amount of money involved. The money is too great to leave.

"So I don't think you can blame what has or hasn't happened here [in IndyCar] as the reason that the Formula 1 drivers aren't showing up. That knife cuts both ways. It might be partly [down to past turmoil in the US], but it's partly down to Formula 1 as well. I would start by saying that."

Where active F1 drivers are concerned it's a pointless question, because there's no way that they can currently run Indy even if they want to due to the date clash with Monaco. But there are other considerations, such as the potential for commercial conflicts. And as Montoya points out, there's also the problem of contracts.

"It's a different time now to when F1 drivers came to Indy all the time," he says. "Now, if you have an F1 contract, they won't let you do anything else. Most driving contracts won't let you drive anywhere other than your current duties. That's kind of normal now. [Racing elsewhere] is a lot more complicated than people think."

Montoya added Monte Carlo glory to his 2000 victory in the Indy 500 © LAT

Montoya also suspects that American racing has moved too far out of the orbit of the European-style racing that forms F1's backbone to resonate with modern drivers in the way that it did for their predecessors.

"If I had started my career in F1 rather than IndyCar, would I still have wanted to race at the 500? I think at some point I would have," he says. "The problem is that when you grow up in European motorsports, there are a lot of people who are not big fans of [American] racing in Europe.

"A lot of European drivers think that racing on ovals is just going around in circles. But the only reason they say that is because they have no idea."

Another aspect to this is how European-based drivers tend to perceive the danger involved with racing on a superspeedway. Drivers ranging from Mark Webber to Scott Speed have ruled themselves out of racing a single-seater on an oval due to safety concerns - Toyota LMP1 driver Mike Conway did likewise, quitting oval racing because he was uncomfortable with it (having suffered an airborne crash at Indy) but continuing in the series on road courses.

Like all forms of motorsport, IndyCar has taken enormous strides with safety, and like all forms of motorsport, it is still not infallible. The spectre of Dan Weldon's crash still looms large, but the biggest accident that IndyCar has seen since - that which ended Dario Franchitti's career - happened on a street circuit.

And since Wheldon's crash, Le Mans has had to absorb Allan Simonsen's fatal accident, and Formula 1 has needed to come to terms with Jules Bianchi's injuries. As safe as modern motorsport is, the potential for life-changing accidents exists at every level.

The danger of oval racing is well known to the outside world © LAT

But there might be an argument to be made that no other category looks as dangerous as IndyCars on big ovals. The speeds are vastly beyond anything that F1 achieves.

Lewis Hamilton's fastest lap at Monza in 2014 was set at an average of 147.249mph. That would have made him a contender in last year's Indy Lights race at the Speedway - and got him black-flagged from the 500 for being 80-90mph off the pace.

True, Hamilton's top speed would have put him a lot closer to IndyCar pace, but he was only achieving that speed for brief flashes on every lap. At Indy, the cars maintain that speed for over two hours. And they do it without the benefit of large run-off areas and tyre barriers to catch them when something goes awry.

"It goes back to safety," says Herbert. "[Indy] is dangerous. People like Rubens Barrichello [who raced in IndyCar in 2012] are rare. The one guy in F1 now who would have loved the era I was in and beforehand; circuits narrow, white lines, grass, a bit of gravel, right on the edge with driver skill ... the one guy who talks about it is Lewis Hamilton.

"He hates the big run-off areas and hates the people going off and coming back on again because he does it very, very rarely, because his mentality is not to use and abuse it. And I love him for that - that's what the skilled world champions have always been able to do. It's all about how close you want to get to that edge.

"It's very different today, so if you are a driver in F1 at the moment the nature of a race like Indy, where you don't have small accidents if it goes wrong, must seem very unusual."

Herbert's stance is backed up by at least one current F1 driver: Lotus's Romain Grosjean.

The 500 is now the domain of domestic racers - like 2015 poleman Dixon © LAT

"I love watching [the Indy 500]," he says. "I've talked to European drivers who went to ovals and they struggled a lot; apparently it's very different. And to be fair, from what I can see from the outside, it's a bit dangerous.

"I really love the racing on the road courses; they're really old-style and interesting. Ovals ... I'd need to try them one day to see if I like them, but so far it's not something that has attracted me. I think my wife would block me from going to ovals."

The other element to the question is, if, by some miracle of scheduling, contract wrangling, and whatever else, Hamilton or Sebastian Vettel did turn up to 16th and Georgetown one May, would they be competitive?

Recent history is not encouraging. Herbert failed to qualify in his only attempt; Piquet was injured in a crash in 1992 and retired with an engine failure when he returned the following year. On the flipside, Mansell was running strongly during his first appearance, but was beaten by Emerson Fittipaldi on a restart.

More recently, NASCAR star Kurt Busch gave an excellent account of himself at Indy last year when he drove an Andretti entry. He had the advantage of a wealth of oval experience to draw upon, albeit in a very different car. One of the biggest obstacles for oval first-timers is learning when to overrule the instincts that have been sharpened by years of road racing.

Would an F1 driver be able to swap large run-off areas for Indy's punishing walls? © LAT

But the real keys to Busch's Indy campaign were that he had a lot of seat time in the lead-up to the event, and that Andretti put all of its resources behind trying to make his car as competitive as possible - it was prepared with exactly the same degree of effort as that given to the team's full-time drivers.

Given the same set of circumstances, Ganassi says that he would have no concerns about running a car at Indy for an F1 driver.

"You look at a guy like Kurt Busch coming over a year ago ... granted, he's a NASCAR guy so it might be a little bit different, but he is certainly a capable driver and you could see that he didn't have any trouble with the speed, and he didn't have any trouble with the car per se," he says.

"Whether I could run a car like that for someone like Hamilton ... it's a good question. I do think those drivers would benefit from something like this in their career; they'd benefit from an Indianapolis 500 exposure. Let's face it, Formula 1 is big around the rest of the world but it's still not big in the US, for whatever reason.

"Give me a Hamilton, a Vettel, a [Valtteri] Bottas, one of those capable guys, and I wouldn't see why, with a little bit of testing and running with any capable team, they wouldn't be fine."

The realities of the modern racing world have created an awful lot of hurdles to stand in the way of us ever seeing Ganassi's optimism really tested. But for IndyCar and F1 fans alike, the prospect of F1's finest once again testing themselves on the biggest one-day sporting stage in the world is an amazing thing to contemplate.

On Sunday, the Indianapolis 500 will be run for the 99th time. But since Ray Harroun won the inaugural race in the Marmon Wasp in 1911, its popularity has ebbed and flowed.

So what does the great race represent today? In this week's AUTOSPORT magazine - available in shops and online from Thursday - Mark Glendenning digs deep into the race's appeal and what it means in 2015.