Brazil's Helio Castroneves opens from the pole position on Sunday in a bid for his third Indianapolis 500 title just over a month after being found not guilty on federal tax evasion charges.

Castroneves, who captured the Indy-car classic in 2001 and 2002, could become only the ninth driver since the race's 1911 debut to win three times at the famed 4km oval known as "The Brickyard".

"It has been very special, no question about it," Castroneves said. "I mean to be sitting on the pole position, obviously I did not think about it. In those moments it was just (hoping) to be back racing."

"I was concerned about how long the trial was going to last so there was a lot of thinking. When you're in the room for about six hours a day, nothing that you can do, a lot of words that you don't understand, you start thinking about a lot of things, you know, other than those words."

Castroneves (34) was charged with not reporting about $5.5-million in income to the US Internal Revenue Service between 1999 and 2004.

The conspiracy charge and six tax evasion counts could have brought him 35 years in prison.

Instead, Castroneves made his return to the series last month and grabbed the inside front row starting spot in 9 May pole qualifying for the 33-car field, edging Penske Racing teammate Ryan Briscoe of Australia.

Briscoe will start in the middle of row one with Scotsman Dario Franchitti, back for the first time since his 2007 victory after an ill-fated season in US stock cars, on the outside of the front row.

All three drivers are well aware that while the race cannot be won on the first turn, defeat could be ensured with a wreck.

"We do have experience," Castroneves said. "Maybe when you're young you're like I want to pass everybody. But I guess we're becoming a little older.

"It's common sense. You respect the other guy. You've just got to keep going and do your own thing. It's a long race."

Franchitti is fine with his outside front starting spot — he won from the same position two years ago.

"It has worked out pretty well," Franchitti said. "It's a long day and if I get ahead of these guys in the first corner, it doesn't really matter that much."

Briscoe, second in the season standings just one point behind Brazilian veteran Tony Kanaan, also expects a smooth start after an outside front row start last year.

"We all sort of got an equal start and sort of gave way to the left," said Briscoe. "We just wanted to get away and get a nice, clean start and get the race rolling. I don't think there's any point in everyone trying to get into turn one three-wide. I hope not."

Row two features American Graham Rahal, defending Indy 500 and Indy-car season champion Scott Dixon of New Zealand and Kanaan, the only man to lead in each of his first seven Indy 500 starts making his eighth Indy 500 start.

Brazil's Mario Moraes, American Marco Andretti — the grandson of 1969 Indy 500 winner Mario Andretti — and Aussie Will Power are in row three.

Danica Patrick, the only woman to lead the Indy 500 and the first to win a major open-wheel race with a triumph last year in Japan, starts on the inside of row four.

Patrick is joined in the Indy 500 grid by two other women racers — fellow American Sarah Fisher on the outside of row seven and Venezuela's Milka Duno on the outside of row 10.

Other international racers include England's Alex Lloyd, Justin Wilson, Dan Wheldon and Mike Conway; Brazil's Rafael Matos and Vitor Meira; Canada's Paul Tracy and Alex Tagliani, Japan's Hideki Mutoh, France's Nelson Philippe, South Africa's Tomas Scheckter, Spain's Oriol Servia, Dutchman Robert Doornbos and Venezuela's E.J. Viso.

Tagliani was inserted in place of Brazil's Bruno Junqueira, which sent his car to the back of the grid in the 33-car field.