The 90th Indianapolis 500 was held at the Indianapolis Motor Speedway in Speedway, Indiana on Sunday May 28, 2006. Sam Hornish, Jr. won the race by passing rookie Marco Andretti on the final lap, about 450 feet from the finish line. It was the first time a driver made a pass for the lead on the final lap for victory in the history of the event.

The margin of victory was 0.0635 seconds, which was the second-closest finish in Indy history at the time. (As of 2014, it is the third-closest). Hornish had earned the pole in qualifying with a four-lap average of 228.985 mph (368.516 km/h). Defending champion Dan Wheldon dominated much of the race, leading 148 laps. However, a punctured tire forced him to make a final pit stop earlier than planned, dropping him to fourth at the finish.

The race was sanctioned by the Indy Racing League and was part of the 2006 IndyCar Series season. With a high temperature of 89 °F (32 °C), it was one of the hottest runnings of the Indy 500 on record.

Chevrolet and Toyota withdrew from the series, leaving Honda as the sole engine provider for all teams for 2006 until 2011. Three races proceeded the Indy 500, and Hélio Castroneves, with two wins and one second place, held a large points lead going into the month of May.

The 2006 race was the first that required all-entries to utilize a 10% Ethanol / 90% Methanol fuel blend.

Several drivers shuffles occurred during the offseason. Defending Indy 500 winner and 2005 IndyCar champion Dan Wheldon switched from Andretti Green Racing to Ganassi. Wheldon started off the season with a victory at the season opener at Homestead. However, the race was marred by the death of Paul Dana during the morning practice session.

...
Wikipedia