Ryan Hunter-Reay set the fastest lap in the first practice session for the REV Group Grand Prix at Road America Friday morning, with an elapsed time of 1 minute, 43.7556 seconds around the 14-Turn, 4.048-mile road course.
Hunter-Reay led Takuma Sato by 0.0688 seconds.
Scott Dixon finished the session third fastest, with a time of 1 minute, 43.9842 seconds, with Will Power finishing fourth fastest with a time of 1 minute, 44.0394 seconds.
Series points leader Josef Newgarden finished the session fifth fastest with an elapsed time of 1 minute, 44.0706 seconds.
The 45-minute session saw the red flag come out twice, both for incidents involving Jack Harvey.
The Meyer Shank Racing driver brought the first red flag out with roughly 26 minutes remaining when his No. 60 Honda came to the stop in turn 12 when his engine shut off.
The second red flag would come out with minutes remaining in the session when Harvey went off track in turn 12 and directly into the tire barrier. Harvey would walk away from the accident unharmed.
Practice 2 for the REV Group Grand Prix of Road America takes place later this afternoon, with live streaming of the session starting at 4:00 p.m. ET on NBC Sports Gold.