Seven Verizon IndyCar® Series drivers completed a one-day test session at Sonoma Raceway on Thursday.

With only two races left in the season, a total of six teams tested the 12-turn, 2.38-mile road course in preparation for the series season finale at the GoPro Grand Prix of Sonoma, Aug. 28-30. It marked the only IndyCar test scheduled for Sonoma before race weekend.

Participants included Juan Pablo Montoya and Will Power (Team Penske), Graham Rahal (Rahal Letterman Lanigan Racing), Scott Dixon (Target Chip Ganassi Racing), Marco Andretti (Andretti Autosport), Sebastien Bourdais (KVSH Racing) and Ryan Briscoe (Schmidt Peterson Motorsports).

"We came up one lap short here last year, but we're in a much better position headed into the race this year," said Rahal, who is currently second in points behind Montoya. "I prefer to have the finale here, on a road course. The new car is pretty physical around here. We're going to have our hands full, and we'll need to be on top of our game."

For the first time in series history, the Verizon IndyCar® Series championship will be decided on a road course, as the 2015 season comes to a close at the GoPro Grand Prix of Sonoma, Aug. 28-30. The list of drivers testing on Thursday included six of the 10 drivers mathematically eligible for the title, with double points on the line at the finale.

"Double points will definitely be interesting here with the hairpins and different strategies; you definitely won't know until the end who's going to win the championship," said Dixon, two-time Sonoma winner and currently third in the point standings.

Mikhail Aleshin, who sustained injuries in a post-qualifying practice crash at the 2014 Verizon IndyCar Series season finale, also got behind the wheel of a Schmidt Peterson Motorsports car for a refresher test.

"Everything is going very well, as it's my first drive in an Indy car since my crash in Fontana. I feel like I'm home," said Aleshin.

 Seven Indy Lights drivers, including the top three in the championship standings, shared the test day in Verizon IndyCar Series cars. Participating Indy Lights drivers included Matthew Brabham (Andretti Autosport), Sean Rayhall (Chip Ganassi Racing), Ryan Phinny (KVSH Racing), Ed Jones (Rahal Letterman Lanigan Racing), Jack Harvey (Schmidt Peterson Motorsports), Spencer Pigot and Nelson Piquet Jr. (Team Penske).

 The 85-lap, high-stakes race in Sonoma carries double points, with 100 awarded to the winner, 80 for second, 70 for third, etc., along with the regular four bonus points over three categories (Verizon P1 Award winner, leading a lap, leading the most laps). Montoya holds a nine-point advantage over Rahal entering the penultimate race of the season Aug. 23 at Pocono Raceway. Dixon, who won last August at Sonoma Raceway, is 34 points out of first place.

 For tickets to the GoPro Grand Prix of Sonoma, call 800-870-RACE (7223) or visit racesonoma.com/indycar. Great packages are available, including the popular Total Access pass, which gets you a race-day reserved-seat ticket in any section and a Garage/Pit/Pre-race pass for just $99.