Indianapolis Speedway...?

May be...

Since its privately owned they don't offically release either figure. Yes it used to be filled every year for the Indy 500 before the open wheel series split.

Its believed to have over 250k seats and has room for another 150k in the infield.

How many people does the Indianpolis Speedway (the track they hold the Indianapolis 500 on) hold? What is maximum capacity and has the race track ever hit maximum capacity?