The 30-minute session will be held just before final practice and will see nine drivers attempting to ‘clean’ the track surface and lay down some extra grip around the 1.25-mile course, which will hold the final oval race of the season on Saturday night.
IndyCar had previously experimented with laying rubber down in the March race at Texas Motor Speedway, running seven cars on the higher groove and which most drivers admitted afterward made a difference, even on the patches of PJ1 TrackBite surfacing which had helped the racing in NASCAR but was treacherous in an IndyCar.
Therefore a similar effort will be made for the 20 August race at Gateway.
Although it has not suffered the same track surface issues, having the high line in play from the start of the race and then accessible throughout the race, can only enhance the passing opportunities.
The drivers participating in the session will be Alexander Rossi (Andretti Autosport), Felix Rosenqvsit (Arrow McLaren SP), Scott Dixon (Chip Ganassi Racing), Takuma Sato (Dale Coyne Racing), Conor Daly (Ed Carpenter Racing), Callum Ilott (Juncos Hollinger Racing), Simon Pagenaud (Meyer Shank Racing), Jack Harvey (Rahal Letterman Lanigan Racing) and Will Power (Team Penske). The only team not represented is AJ Foyt Racing.
Each car will be granted one extra set of Firestones for this session, which will be returned at the end of the half-hour. Fifteen minutes later, the final one-hour practice for all cars will begin.
The race will then take place on the Saturday, with green-flag running beginning at 5:30pm CDT (11:30pm BST).