There was gridlock. There were lines.

But the sold-out running of the 100th Indianapolis 500 somehow got off to a splendid start with most fans in their seats in plenty of time before the green flag waved. Speedway spokeswoman Suzi Elliott said he was unaware of any significant complaints.

Fans left for the track early — very early.

"I think people who come every year were very much aware that you're going to have another 150,000 people here, so they really did a good job," said Jim Robisch, a 61-year-old fan from nearby Pittsboro, Indiana. "All my friends were saying 'Well, when are you going? We're leaving two hours early.' That's what we did. We left two hours earlier than we normally would to go to a typical 500."

Some locals left their homes track as early at 3 a.m., just so they could get a good parking spot, and it may have contributed to a quieter night than usual. The Indianapolis Star reported only two arrests were made overnight, both for public intoxication.

By 8 a.m., the Pagoda Plaza was already a prime people-watching spot, packed with fans from side to side. Gasoline Alley was filled with colorful cars going through technical inspection, celebrities there to take it all in and fans mingling with drivers and teams.

Celebs walking the red carpet included "Star Trek" star Chris Pine, rapper Ice-T and Nick Gehlfuss of "Chicago Med."

Lady Gaga was also at the speedway, dressed down in jean shorts with her hair pulled back in a tight ponytail. She replaced Keith Urban for what IndyCar called a "high-speed thrill ride" during the parade laps alongside 1969 race winner Mario Andretti in a customized two-seat Honda.

Outside the sprawling speedway, other than some unexpected road closures things went relatively smoothly for what is expected to be the world's largest single-day sporting event this year.

"It only took us 2 1/2 hours," said Jackie Kuhens, a 56-year-old Louisville, Kentucky, resident who made the 110-mile drive Sunday morning. "We park only a block and a half away from here and it worked out perfectly."

Race organizers announced 2 1/2 weeks ago that all reserved seats had been sold for the first time in at least two decades. Last week, the infield also was sold out and the local television blackout was lifted for the first time since the 1950s.

When the gates opened at 6 a.m. with the traditional firing of the cannon, the massive crowd moved through the lines faster than anticipated with enhanced security — a stark contrast to a few years ago when fans complained about long delays at the gate. Speedway officials have taken steps such as opening more gates and using private security workers to get people inside.

"I'm really impressed with how fast we came through here," said Mark Yarber, a 63-year-old fan from Nashville, Tennessee.