Highlights from the 55th running of the Indianapolis 500

RACE: 55th Indianapolis 500

DATE: May 29, 1971

WINNER: Al Unser Sr.

AVERAGE SPEED: 157.735 mph

WHAT HAPPENED: Unser won for the second consecutive year and became the only driver to win on his birthday. He was the first winner to celebrate in the relocated victory lane, which now sported black-and-white checkered ramps and was in the ''horseshoe'' area near the start/finish line.

NOTABLE: An Indianapolis-area car dealer was the driver of the pace car, but he lost control of the Dodge Challenger at the south end of the pits at the start of the race. The car crashed into a photographers' stand, injuring 29 people.