Mazda topped the opening Practice session for the Continental Tire Road Race Showcase with a 1-2 result led by Jonathan Bomarito.
Bomarito set a time of 1:56.623 on the Friday afternoon session, in the No. 55 Mazda Prototype, which he co-drives with Tristan Nunez.
Joel Miller came in second in the No. 70 Mazda, with a time that was 0.231 seconds shy of his teammate.
The Mazdas were the only cars to dip into the 1:56s at Road America. Ricky Taylor came third in his No. 10 Wayne Taylor Racing Corvette DP, with a 1:57.340.
A 2:00.519 from Stephen Simpson in the No. 85 Oreca FLM09 run by JDC-Miller Motorsports was the best out of the Prototype Challenge runners, with PR1/Mathiasen Motorsports taking second.
Richard Westbrook topped the GT Le Mans category, setting a time of 2:03.823 in his No. 67 Ford Chip Ganassi Racing Ford GT, with the sister No. 66 car in second.
In GT Daytona, Paul Miller Racing led the way with the No. 48 Lamborghini Huracan GT3. Madison Snow took that car to a 2:08.018 early in the session.
The action was only stopped once, with a four-minute red flag period to recover the No. 63 Scuderia Corsa Ferrari 488 GT3 which was lost in the gravel at Turn 12.
Other than that, the session was relatively clean. Practice 2 is scheduled for 4:45 p.m. local time.
RESULTS: Practice 1