Mikhail Aleshin led a Schmidt Peterson Motorsport 1-2 in opening practice at the Pocono Raceway on Saturday as three drivers found the wall.
Aleshin set a best lap of 221.932mph to set the pace ahead of team-mate James Hinchcliffe, but the session saw Ryan Hunter-Reay, Charlie Kimball and Juan Pablo Montoya all hit the unforgiving concrete wall.
Hunter-Reay crashed his Andretti Autosport machine at turn one early in the session to cause the first interruption on just his sixth lap of the day, while Kimball hit the same wall in his Chip Ganassi Racing entry later in the session. Team Penske driver Montoya hit the wall at turn two with five minutes remaining on the clock.
All three drivers were unhurt, but with qualifying only three hours away, the teams will face a race against time to get their drivers out.
Josef Newgarden ended the session in third for Ed Carpenter Racing ahead of Alexander Rossi of Andretti Herta Autosport, with Carlos Munoz placing his Andretti Autosport machine into fifth.
Championship contender Will Power was sixth in his Penske machine, three-tenths of a second but eight places ahead of team-mate and championship leader Simon Pagenaud.
Tony Kanaan was the leading Ganassi driver in seventh ahead of Kimball and Montoya, while Ed Carpenter completed the top ten.
Pocono Free Practice 1 Result
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