#9-William Byron was fastest during opening practice at Phoenix International Raceway with a speed of 135.957mph. #41-Ben Rhodes, #18-Noah Gragson, #88-Matt Crafton, #51-Daniel Suarez, #21-Johnny Sauter, #8-John Hunter Nemechek, #98-Rico Abreu, #17-Timothy Peters, and #4-Christopher Bell followed in the top-10. 29 drivers practiced during the session. See complete results on the Phoenix practice 1 speeds page (pdf).
