#62- Brendan Gaughan was fastest during opening practice at Chicagoland Speedway with a speed of 178.601mph. #54-Kyle Busch was second, followed by: #31-Dylan Kwasniewski, #2-Brian Scott, Chris Buescher, #5-Kevin Harvick, #9-Chase Elliott, #43-Aric Almirola, #20-Denny Hamlin, and #42-Kyle Larson. All 44 drivers practiced during the session. See complete results on the Chicago practice 1 speeds page (pdf).
