INDIANAPOLIS -- Five-time Formula One champion Michael Schumacher walked around Las Vegas virtually unrecognized while taking a brief vacation before this weekend's U.S. Grand Prix. A couple days later, about 15,000 people showed up at Indianapolis Motor Speedway for an F1 pit lane walkabout.

Rest assured, all of those fans knew who Schumacher was.

But the above scenario raises an interesting question. People have been saying for years that F1 needs to increase its fan base in the United States. But is developing a broader U.S. audience as critical as some contend? Or is it something often said but not really pursued in a tangible way?

Like many things in F1, there is no simple answer but plenty of opinions about the subject.

"If you are trying to increase the opportunity for Americans to follow F1, then you are going to have a bigger base," said Eddie Cheever, one of the last U.S. drivers to race in F1 and now a team owner in the IRL. "F1's survival definitely does not depend on that. It would be an added benefit because this is the largest single economy in the world, so it would seem silly to not put that effort into capitalizing on that opportunity."

A stable home Grand Prix and a successful American driver are two keys for F1 to grow in popularity in the U.S.

The first of those is in place. Contrary to some unfounded reports, F1 and Indy are not about to part company. F1 needs Indianapolis, and vice versa; the partnership is quite successful.

While Indianapolis Motor Speedway never releases official crowd figures, Sunday's race attendance is expected to be as good or better than last year's crowd of 125,000. The best-attended race so far this season was the European Grand Prix at Germany's Nurburgring that drew 123,000, and only three other races this year have had more than 100,000 spectators on Sunday.

True, tickets are more expensive at the European races than they are at Indy. But on the other hand, Europe is the center of the F1 world and has a dense population base. The bottom line is this: The U.S. Grand Prix pulls in one of the largest F1 crowds of the season.

"I think the number of people who come here is amazing," said Williams BMW driver Juan Pablo Montoya. "But the point is that the grandstands are so big that it looks half empty. I think if the people can get to understand F1 more they are going to love it even more."

	Rubens Barrichello and his Ferrari only race in America once a year; some say twice would be appropriate for such a big market.

Getting a successful U.S. driver into F1 is going to take a few more years, but when it happens it will provide a huge boost for F1's popularity in this country. Witness what Montoya is doing for F1 in Colombia; what Fernando Alonso is doing for F1 in Spain (100,000 people showed up in Madrid to see him at a PR function); and what Mario Andretti did for F1 in America in the 1970s.

Rick DeBruhl, who covers Formula One for Speed TV, points to what Lance Armstrong has done to increase the recognition of the Tour de France and bicycle racing in general in the U.S. A successful American Formula One driver could do the same.

The Red Bull scholarship program, headed by former Indy 500 and F1 driver Danny Sullivan, is in its second year. It's a program that will last at least five years and find, finance and promote young U.S. drivers on the road to F1 via the various stepping stone series' in Europe.

BMW has just announced that it will launch a junior single-seater racing series in the U.S. to create an environment to help young drivers possibly reach Formula One.

"This series is aimed at 15, 16, 17-year-old kids who come out of karting and get their first single-seater car," BMW Motorsports director Dr. Mario Theissen said. "We are not only providing the car and the series, but we are also providing an educational program to (help one) become a racing driver and to learn everything it takes to develop in the world of motorsport and to be able to make his or her way in motorsport. It's a very big commitment. This is the first step to enable young drivers to become a F1 driver."

"For us it would be very positive to have an American driver in F1," Theissen added.

The U.S. market is crucial for the major auto manufacturers involved in F1 as this is one of their biggest markets. Many of them would like to see two Grand Prix races in the U.S.

"The American market is the most important market for BMW," Theissen said. "We would very much like to see the importance of F1 in the States growing.

"So far, of course, our colleagues here in the U.S. are not really happy about the impact of F1, and everybody would love to see F1 gaining importance in North America. We are on an upgrade slope and I very much hope we continue on that."

Honda sells about 50 percent of its cars in North America.

"It's good that F1 comes here," said Honda Racing Development vice president Otmar Szafnauer, who grew up in Detroit. "Two races here wouldn't go amiss, perhaps one here (in Indianapolis) and perhaps one on the West Coast. It's a big country."

Mercedes-Benz racing chief Norbert Haug stressed that F1 needs to do more for the fans at the racetracks.

"The American market is a very important one," he said. "We have record sales here again this year. You can see we are focused on this Grand Prix. We've had track advertising here (at Indy) for a couple years, which is not usual for us but we wanted to set a sign as the brand Mercedes-Benz and show our commitment to the U.S. and especially to Indianapolis."

F1 team personnel were impressed with the fan turnout for the pit walk at Indy on Thursday.

"We have to make sure that the show doesn't decrease but increases to make sure that the response of the public is there," Toyota Racing team manager Ange Pasquali said. "It was quite interesting to see this pit walkabout...the amount of people was just amazing for a first day when you have no cars running on the track. So we have to work at that for the future. I think it's quite promising for the future."

Renault doesn't sell its name-branded cars in North America, but it does sell its sister marque Nissan. The global aspect of Formula One cannot be minimized, stressed Renault executive director of engineering Pat Symonds.

"Yes, we're racing in America this weekend, but we are broadcasting that race all over the world," Symonds said. "I'm very pleased to be racing in America. A World Championship is not a World Championship unless it involves North America."

One example of a Formula One global marketing plan that isn't aimed at North America is Budweiser's sponsorship with Williams; that is solely designed to promote Budweiser worldwide.

"Budweiser won't use F1 for the American market," Williams' head of marketing Jim Wright told ESPN.com. "They have got NASCAR and all their other programs. Budweiser are using F1 for expansion into European and Asian markets."

Most F1 teams and sponsors were upset when the popular Canadian Grand Prix was dropped off the 2004 schedule because of a tobacco advertising ban in that country. There's a chance the Montreal race will be reinstated, but if it doesn't happened, will it hurt F1's increasing fan base in the U.S.?

"Many people view America as starting in Canada and ending up in Mexico City," Cheever said. "So you would have to say it would hurt."

In the short run, the loss of the Canadian Grand Prix would benefit the Indianapolis F1 race in terms of increased ticket sales because fans in North America would have only one F1 race. But in the long run, having no Canadian G.P. is detrimental because it cuts in half F1's exposure in North America.

Former driver-turned-commentator David Hobbs says people are wrong to think the U.S. doesn't care about Formula One racing.

"I think that the fan base in F1 is bigger than people give it credit for," Hobbs told ESPN.com. "For example, in Milwaukee, which you would not call the hotbed of F1, I can't believe the amount of people who watch the F1 shows. The fan base is pretty good. Obviously it could always be expanded."

F1 is the king of all racing in the rest of the world. Witness the $50 million a year that Schumacher is estimated to rake in, or the $20 million contract Jacques Villeneuve has with BAR. But the series has major-league competition inside the United States.

"The one thing that F1 finds difficult to come to grips with here is that there are so many other racing series," Hobbs said. "It's unlike in Europe where there is hardly any serious professional racing. You got the DTM, and the touring cars championships, but they don't have a CART, an IRL and the big monkey on your back -- NASCAR. There is a huge support for racing here."

For F1 to truly make headway in the U.S., Hobbs said, it would need to address NASCAR's domination in the mainstream media.

Asking Formula One to attain media coverage and TV ratings enjoyed by the NFL and NASCAR in America obviously is asking too much. But there are those working to slowly and steadily grow F1 in the United States; we'll see if those efforts pay off.

Dan Knutson covers Formula One for National Speed Sport News and ESPN.com.