The season was historically significant, as IndyCar became the single major open wheel racing series in the United States.

[5] On February 19, 2008, Robin Miller reported on SPEED and Curt Cavin blogged on IndyStar.com that the managements of Indy Racing League and Champ Car have come to an agreement to become one entity.

Meanwhile, Brian Barnhart announced that Tony George is negotiating the unification, and an inventory of available IndyCar chassis and equipment for the Champ Car teams is underway.

[14][15][16] Prior to the unification, the bigger news surrounding IndyCar on the sporting side was the departure of its two most recent champions and Indianapolis 500 winners to the NASCAR Sprint Cup Series.

[18] At the same time, four-time Champ Car champion Sébastien Bourdais had departed the rival series to join Formula 1, a year after Allmendinger went the NASCAR route that teammate Paul Tracy almost followed.

[23] Off the track, Hélio Castroneves became a massive sensation and attained celebrity status after participating and winning the fifth season of ABC's Dancing with the Stars.

[25][26] Andretti Green Racing driver Danica Patrick, who already enjoyed major national recognizition, further expanded her reach by prominently featuring in the Sports Illustrated Swimsuit Issue.

O  Oval speedway R  Road course S  Street circuit NC Non-championship race † – The Indy Japan 300 was originally scheduled for April 19, but was postponed to the next day due to multiple weepers on the track.

[161] The five transitioning Champ Car teams were scheduled to test on March 19–20, but only six drivers took part as Newman/Haas/Lanigan and HVM Racing were not ready in time.

The early part of the race saw several spins by several cars, including Danica Patrick, Marco Andretti and Mario Moraes.

Several cautions slowed the race, including a crash by Ryan Briscoe, and a multi-car incident involving Vítor Meira, Franck Perera, and Townsend Bell.

[171] He also became the fourth driver to win an IndyCar Series race in his first start, joining Buzz Calkins, Juan Pablo Montoya and Scott Dixon.

The final race of the Champ Car era took place less than a day after the checkered flag fell at the Indy Japan 300.

The race was run under Champ Car rules, which included the standing start, option tire, two-day qualifying format, ran on time (1hr 45 mins) rather than a set number of laps.

Several cars, including Tony Kanaan, Graham Rahal, Jeff Simmons and Justin Wilson were involved in crashes.

In the first half, three single-car incidents involving Mario Domínguez, Justin Wilson, and Oriol Servia slowed the race.

John Andretti's pitcrew had trouble engaging the fuel hose, and he dropped back the end of the running order.

On the lap 227 restart, Marco Andretti and Scott Dixon passed Danica Patrick to take third and fourth place respectively.

During the caution, a handful of cars pitted, including Danica Patrick and rookie Jaime Camara, but most of the leaders stayed on the track.

On lap 6 Hélio Castroneves, who had started last after being unable to post a time in qualifying due to a broken throttle, snapping his streak of three consecutive poles at Watkins Glen, had a gearbox problem and stopped just shy of pit lane.

After a brief interlude when Vítor Meira led during a pit stop cycle, Briscoe and Dixon returned to the top two positions and thoroughly dominated the race, leading third-place Hunter-Reay by over 20 seconds.

However, Meira and E. J. Viso made contact in turn 8 and the ensuing caution period allowed the other lead-lap cars to catch up to Briscoe and Dixon.

Hunter-Reay, who had no need to conserve fuel, newer tires, and a stronger car, easily dispatched of Manning in a short green-flag period before another caution came out for Jaime Camara's crash in turn 6.

This race had a shuffling finish, with Dixon, Andretti and Meira each leading at least one lap in the dying stages before pitting for splash-and-go stops.

But on the final corner, Castroneves ran out of fuel and Dixon flew past to take his sixth win of the season.

Later the same lap Castroneves had a right rear puncture caused by Danica Patrick's front wing while passing the Andretti Green Racing driver.

Lap 17 saw the end of Power's dominance of the meeting as he crashed at the Bartercard chicane, which put Briscoe into the lead ahead of Dixon.

At the same time Graham Rahal touched the rear of Ed Carpenter, spinning the Vision Racing car around, almost blocking the track.

Dario Franchitti clipped the tyre bundle on the inside of the same chicane and spun and stalled bringing out the safety car.

Carpenter hit the wall at turn 3 on the last lap but it did not affect the lead battle and Briscoe won his home race ahead of Dixon and Hunter-Reay finished third.