For everyone that’s asking about the Thursday Open House, it is SO worth it if you can make it! The pits open at 9am and basically you haul ass to the track in the morning & they have buses to take people straight to the pits where you can walk around, see the garages, meet with the pit crews (and the drivers!!) and experience the atmosphere. A lot of the drivers do their track walks at this time as well, so it’s certain that you’ll run into a few coming back to the pits or while you’re going around on the bus.
Of course, starting at around 11? the drivers start their Autograph session, but they rotate the drivers every 10-20 minutes or so. The line gets /long/ for that but a vast majority of the drivers do make it out for this autograph session. You can stay until noon when the pits officially get to work with race prep.