Team and driver changes

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.

Marco Andretti moved up from the Indy Lights series and took over the vacated spot at Andretti Green Racing. In December, team owner Michael Andretti announced he would come out of retirement to race at Indy, alongside his son. Similarly, owner/driver Eddie Cheever announced he would get back into the car, participating in four races, including Indy.

Tomas Scheckter moved from Panther to Vision Racing. Vítor Meira took over the vacant spot at Panther, leaving the Rahal team. Paul Dana was signed as the third car for RLR, but was replaced by Jeff Simmons after his tragic fatal crash. Rahal maintained the services of Buddy Rice and Danica Patrick.

After a brief retirement, Al Unser Jr., who missed the 2005 race, signed with Dreyer & Reinbold Racing. Unser would race alongside teammate Buddy Lazier, who signed on for a partial season ride at DRR.

Hemelgarn Racing signed P. J. Chesson with financial backing from NBA basketball player Carmelo Anthony.^[1] An aggressive marketing campaign nicknamed the entry "Car Melo", and also acquired the services of Jeff Bucknum for a two-car effort. However, by month's end, a disastrous result saw the two cars crash out together on lap 2, placing 32nd-33rd respectively. Hemelgarn subsequently closed its doors for the remainder of the season.

Rookie Orientation - Sunday May 7

Opening day featured rookie orientation and refresher tests. The day opened with the Andretti family celebrating three generations (Mario, Michael, and Marco) taking a ceremonial lap around the track together.

Michael Andretti, Al Unser Jr., and Arie Luyendyk Jr. participated in refresher tests. Rookies P. J. Chesson and Marco Andretti passed the four-phase rookie test. Townsend Bell took only "shake down" laps. Michael Andretti (220.999 mph) was the fastest car of the day.

Rookie Orientation - Monday May 8

The second day of rookie orientation saw Thiago Medeiros pass the rookie test. Townsend Bell (221.381 mph) was the fastest car of the day.

Tuesday May 9

The first full day of veteran practice. Sam Hornish Jr. (224.811 mph) was the fastest car of the day.

Wednesday May 10

Sam Hornish Jr. (226.056 mph) was the fastest car of the day. The track closed early due to rain at 3:30 p.m.

Thursday May 11

Rain delayed the start of practice until nearly 2 p.m. Marty Roth spun in turn two, but made no contact. Sam Hornish Jr. (226.789 mph) was the fastest car of the day.

"Fast" Friday May 12

Rain washed out practice for the day.

Saturday May 13

Time trials was scheduled for four days. The "11/11/11" format was to be utilized, with eleven positions available on pole day. However, rain washed out time trials for the day. Pole day qualifying was rescheduled for Sunday May 14.

Sunday May 14

The "11/11/11" format was scheduled to be used, and thus 22 position were to be open for qualifying on Sunday May 14. Rain continued to fall, but the track dried shortly after 1 p.m. The cars took to the track for practice for about an hour, and Dan Wheldon turned the fastest lap of the month at 228.663 mph. At 2:15 p.m., the rain resumed, and the track was closed for the day. Time trials was washed out for the entire weekend for the first time since 1983.

Wednesday May 17

Sam Hornish Jr. (224.381 mph) was the fastest car of the day. Rain closed the track early at 4:26 p.m.

Thursday May 18

Rain kept the track closed until 3:45 p.m. Arie Luyendyk Jr. and Thiago Medeiros suffered crashes. The brief session was ended at 5:52 p.m., as rain fell again. Sam Hornish Jr. (224.381 mph) was the fastest car of the day.

"Fast" Friday II May 19

Sam Hornish Jr. (227.925 mph) was the fastest car of the day. Hornish led the speed charts on all three practice days during the second week. Marty Roth spun but made no contact. Jeff Simmons crashed in turn one, but was uninjured.

Pole Day - Saturday May 20

Since the first two days of time trials were rained out, 33 positions were available for time trials on May 20. The field was filled to 32 cars by the end of the day. Sam Hornish Jr., won the pole with the fastest four-lap qualifying speed of 228.985 mph (368.516 km/h).

Only one driver waved off during the day. Dario Franchitti experienced engine trouble after three laps, but later completed his attempt after an engine change. Although the new qualifying rules allowed qualified cars to be withdrawn and re-qualified in hopes of gaining a better starting position (with a maximum of three attempts per day), only one driver took the opportunity to do so. Townsend Bell's qualification run of 223.659 mph (359.944 km/h) was withdrawn, and he achieved an average of 224.374 mph (361.095 km/h) on his second attempt. This improved his starting position by only one spot.

Bump Day - Sunday May 21

The day opened with one position open in the field, and two drivers prepared to make an attempt. Rookie Thiago Medeiros, who had crashed his lone car on Thursday, returned to the track for practice.

Most of the afternoon focused on race day practice for already-qualified cars. Sam Hornish Jr. (226.256 mph) led the speed charts for practice laps, capping off a month where he led the speed chart every day he took practice laps except one.

Marty Roth was the only driver besides Medeiros that was looking to make an attempt. At 3:30 p.m., polesitter Sam Hornish Jr. spun in turn one and hit the outside wall while practicing in a backup car. He was uninjured.

With about an hour to go, A. J. Foyt brought a backup car to pit lane, driver Ryan Briscoe was getting settled into the car, fueling rumors of a late qualifying run.

At 5:08 p.m., Thiago Medeiros completed a qualifying attempt, and filled the field to 33 cars, however he was slowest and now on the bubble.

With 23 minutes left in the day, Marty Roth spun during a practice run, and crashed into the outside wall in turn 1. He was not injured, but the car was wrecked, and his chances to qualify were finished. The day ended with Medeiros the only car to complete an attempt for the afternoon with Briscoe deciding against making a run.

Carb Day - Friday May 26

Sam Hornish Jr. once again led the speed charts (220.698 mph). It was the ninth day of the month that Hornish completed the fastest practice lap.

Penske Racing with driver Hélio Castroneves won the 30th Annual Checker's/Rally's Indy 500 Pit Stop Challenge.

Failed to qualify

• 25 - Marty Roth — Wrecked during practice.

Start

After considerable rain during the month, race day was sunny and hot. Temperatures topped out at 89 °F (32 °C), one of the hottest days for the Indy 500 on record.

Due to the state of Indiana observing Daylight Saving Time, the start of the race was scheduled for 1:11 p.m. EDT. Mari Hulman George gave the command to start engines at 1:04 p.m. EDT, and all 33 cars pulled away for the pace laps, with Lance Armstrong driving the pace car.

Sugar Ray Leonard waved the green flag to start the race, and polesitter Sam Hornish Jr. took the lead into turn one. Down the back stretch, Hélio Castroneves passed Hornish for the lead, and Dan Wheldon moved into second. Castroneves led the opening lap.

On the second lap in turn two, Jeff Bucknum spun out and collected his teammate P. J. Chesson, taking both of the entries from Hemelgarn Racing out of the race and sadly out for the remainder of the season.^[4]

First half

After the Hemelgarn incident, a long period of green-flag racing ensued, lasting 60 laps. During this period, Dan Wheldon dominated the race, briefly losing then regaining the lead during a round of green-flag pit stops around laps 36-39. By lap 64, Wheldon had built up a 19-second lead—nearly half a lap—over the next nearest competitor, and after 65 laps had lapped twenty-five of the other cars in the race, including all five of the other former 500 winners, leaving only eight cars on the lead lap.^[4][5][6][7]

The field tightened during a yellow flag on lap 67 due to a crash by Tomas Scheckter. The crash sent debris into the inside grandstand, injuring five spectators, none seriously. Wheldon maintained the lead through a series of pit stops, and led at the halfway point.

Second half

Wheldon gave up the lead briefly during pit stop on lap 108, which allowed Scott Dixon to lead.^[4][8]

On lap 110, Hélio Castroneves struck Buddy Rice from behind, taking out both cars. It was the first time two former winners had been involved in the same crash in the Indy 500 since 1992.^[4][9] It was also the first time in his career that Castroneves failed to finish the race.

Sam Hornish Jr., took the lead from Wheldon on lap 130. Wheldon, however, would regain the lead on lap 145 and hold it through lap 182.^[4]

On lap 149, Al Unser Jr. precipitated a caution period after spinning down the back-stretch and crashing in turn 3. During the caution, Jeff Simmons left the pit area with the fuel hose nozzle still attached. The hose tore, and Simmons's car dropped the nozzle out on the track in turn 3. On lap 150, the leaders pitted. Sam Hornish Jr. started to pull out of his pits with the hose still attached. The hose ripped, but Hornish stopped in the pits allowing the crew to disengage the nozzle. Team owner Roger Penske accepted responsibility for the error, having told Hornish to go before the fueling was complete. Fuel spilled in the pit stall, but Hornish was able to return to the track and stay on the lead lap.

Still under caution on lap 155, the field was preparing to go back to green when Jeff Simmons wrecked in the north chute. The caution was prolonged. On lap 160, Michael Andretti and Sam Hornish Jr. ducked into the pits to top off their fuel. Both would be able to make it to the finish without another pit stop.^[4][8] On lap 163, the green came back out with Dan Wheldon leading. Sam Hornish Jr. was assessed a "drive-through" penalty (being required to drive once through pit road, without stopping, obeying the pit road speed limit) for the pit violation moments earlier. Hornish returned to the track over 30 seconds behind the leader, but he was still on the lead lap.

With twenty laps to go, Dan Wheldon and Tony Kanaan were running nose-to-tail in 1st-2nd. All of the lead lap cars would need to make one final pit stop for fuel, except for Sam Hornish Jr. and Michael Andretti. Eighth place Hornish was less than 10 seconds ahead of Wheldon and Kanaan, barely clinging to the lead lap. Down the backstretch on lap 183, Wheldon came up on the lapped car of Kosuke Matsuura, and was momentarily blocked. Kanaan darted into the lead on the inside. But in turn three, Kanaan and Wheldon split the slower car of Max Papis, going three-wide through the northchute. Wheldon got up into the marbles in turn four, and punctured a tire. As they went through turn one on lap 184, Wheldon nearly got sideways, and he had to back off his pace. Wheldon immediately headed for the pits for tires and fuel (a few laps earlier than planned). But due to the puncture he lost several seconds on his in-lap.

Tony Kanaan was now in front, with Andretti Green Racing teammates holding the top four spots (Kanaan, Marco Andretti, Dario Franchitti, and Michael Andretti).^[4] Seven cars were on the lead lap, with Hornish in 6th and Wheldon now down to 7th, both clinging to the tail end of the lead lap.

Late Race Caution and Finish

Marco Andretti, running second, went to the pits for fuel on lap 190. As Marco Andretti was pitting, Felipe Giaffone crashed in turn two, bringing out the yellow. Marco Andretti (legally) slipped by the pace car exiting the pits, and avoided losing a lap in the shuffle. Leader Tony Kanaan, who still needed to pit, was stuck out on the track as the pits were closed at the onset of the yellow. The pits re-opened as the field came by for lap 193. Kanaan and Dario Franchitti ducked into the pits for fuel. Fan-favorite Michael Andretti stayed out on the track, and assumed the lead. Michael had come out of retirement to race with his 19-year-old son Marco, who cycled up to second place. In his 15th Indy 500, Michael was still looking for his first Indy victory. Scott Dixon was lined up third, and Sam Hornish Jr. was now up to fourth.

The green came out with 4 laps to go. Michael Andretti led the field, with his son Marco close behind in second. Hornish made a desperate pass deeper in the field, and emerged in third place as the field exited turn 2.

With three laps to go, Marco Andretti pulled outside of his father down the frontstretch, and passed his father for the lead in turn 1. Marco began to pull away as Michael now assumed a blocking role to protect his son's lead. Down the backstretch, Michael tried but failed to hold off the charging Hornish, and Hornish took over second place.

With two laps to go, Marco led Hornish by a half second, with Michael still in third. Down the backstretch, Hornish tried to squeeze past Marco as they approached turn three. He was pinched down, and ran out of race track, and had to back off. Hornish lost his momentum, and Marco pulled out to a 1-second lead at the start/finish line with one lap to go.

On the final lap, Marco held his lead down the back stretch. In turn three, however, Hornish began to reel him in. As the two cars exited turn four, Hornish executed a slingshot pass in the final 400 feet. He beat Marco Andretti to the finish line by 0.0635 seconds, the equivalent of about 15 feet (4.6 m). It was the second-closest finish in Indy 500 history. It was also the first time in Indy history that a driver made a pass for the lead to win the race on the final lap.

Afterwards, Hornish commented on his last-second pass, "I figured I came all this way, I ought to give myself one more shot at it. I kind of looked at it as, I was going to drive over him if I had to. For Marco to come as a rookie and drive like that he should be proud no matter what."^[4][8][10]

Third-place finisher Michael Andretti had high praise for his son: "I felt so bad for Marco, but I'm so proud. He drove a hell of a race. I drove with him a hell of a lot in that race. He drove like a champion. He drove like he's been out there 10 years." But Marco wanted more: "I do not want to wait until next year. I have to take advantage of everything because second's nothing," he said.^[10][11]

After leading 148 laps, 2005 winner Dan Wheldon failed in his bid to win back-to-back races. He recovered from the punctured tire on lap 183 to finish in the top five. On the final lap, while most of the attention was focused on Andretti and Hornish, Wheldon slipped by Tony Kanaan for position going into turn three, and came home fourth.

Race statistics

Radio

The race was carried live on the Indianapolis Motor Speedway Radio Network. Mike King served as chief announcer.

For the second year in a row, pit reporter Kevin Olson conducted a pre-race interview with David Letterman. This would be the final 500 on the radio for Adam Alexander.

Television

The race was carried live flag-to-flag coverage in the United States on ABC Sports, except in Indianapolis on WRTV, where it was tape delayed to primetime due to the seats not completely sold out. After a critically unpopular season as chief announcer for the IndyCar series on ABC/ESPN, Todd Harris was removed from the broadcast booth. Veteran announcer Marty Reid took over as play-by-play. Scott Goodyear returned as driver analyst. Joining them in the booth was 1989 NASCAR Winston Cup Champion Rusty Wallace, who served as co-analyst with Goodyear.

For the first time ever, the broadcast utilized the Side-By-Side feature during commercial breaks. This was also the final "500" broadcast solely in standard-definition.