INDIANAPOLIS - In the past, there was usually little strategy involved in trying to win the pole for the Indianapolis 500. Just hold the gas pedal down and drive.

Thanks to the qualifying format adopted two years ago, today's opening day of time trials for the May 25 race could be a strategic nightmare.

"This year, it's going to be such a mess," said Scott Dixon, the fastest driver in this week's rain-abbreviated practice on the 2.5-mile Indy oval with a lap of 226.968 mph Friday, considerably faster than the four-lap average of 225.817 that won the pole for Helio Castroneves last May.

In fact, the five quickest drivers on "Fast Friday," the final full day of practice before qualifying, were faster than last year's pole. But it isn't as simple as just being fast now.

The unique, four-day Indy qualifying format limits the number of qualifiers to 11 on each of the first three days, then uses the fourth and final day to bump the slowest drivers already in the 33-car lineup.

Making it even more difficult, each car is allowed up to three chances per day, with the teams allowed to withdraw an already-qualified car to try to go faster.

With the recent unification of the two American open-wheel series, there are more car-driver combinations here for the first weekend of time trials than in any year in the past decade. Thirty-three cars made it onto the track during Friday's busy session, turning a total of 1,033 laps.

Dixon said he expects a lot of those drivers, particularly the ones transitioning from the now-defunct Champ Car World Series, to be chasing position No. 11 just as hard as the favorites drive for the No. 1 spot today.

"Twenty or twenty-two or maybe more cars are fighting for that spot," Dixon said. "They're going to clog up the [technical inspection] lines and things like that.

"It could be a tough day for everybody."

The rookies got two full days of practice Sunday and Monday, while the veterans had one dry day on Tuesday before Friday's session, cut about three hours short by yet more rain. Dixon moved to the top of the speed chart, just ahead of Marco Andretti's 226.710, Tony Kanaan's 226.688, Ryan Briscoe's 226.143 and rookie Hideki Mutoh's 225.990.

But the New Zealander, who drives for Target Chip Ganassi Racing, doesn't consider himself the favorite.

"To be fast on 'Fast Friday,' I've been in this spot before and it hasn't worked out well for me in the past," Dixon said. "It was a bit tight out there [in traffic], hard to get clear laps, so you don't really know where you are. Everybody's speed fell off an awful lot when they were in the clear.

"I think, in the morning, we're going to decide if we've got a legit shot at the pole. ... We can't waste tires or energy on going for it if we don't have a great shot at it."

Andretti, a third-generation IndyCar driver who finished second in the 500 two years ago as a 19-year-old rookie, believes he and Andretti Green Racing teammate Kanaan are definite pole contenders. He welcomed this week's rain.

"We're ready," said Andretti, who was also over 226 on Tuesday. "Bring on tomorrow. We're just hoping that, hopefully, [the rain] is just separating us from our opposition."

"The car has shown definite signs of consistency right from the start, which is definitely a positive. We're just working on what I'm sure the majority of the field is working on -- taking off downforce and still trying to keeping the balance in the car."

Castroneves, a disappointing 11th on Friday's speed list, got in only 31 laps before the rain came.

"It's too bad we couldn't run more today," the two-time Indy winner and two-time pole winner said. "I would have liked to have done a few more things out there, but I still think we're in good shape for tomorrow.

"I'm not concerned with the other drivers' speeds today because I think a lot of them were getting tows [from other cars]."

Oriol Servia, one of the transitional drivers, was 16th on Friday and happy with his progress.

"It's hard to tell because everyone gets towed, and we did, too," Servia said. "But I'm happy with how the car feels and that is the most important thing. I think ... we may have a shot at being in the top 15 and, if we do it right, we could be in the top 11."