That's 250 gallons of gas. Even if you are driving a huge truck that gets 10 mpg, that would be 2500 miles of driving.
Do 30% of the race fans come from over a thousand miles away?
They aren't driving Hondas. lol
When I went with friends to see the Daytona 500 back in 1989, I was surprised by the number of friends they had who all showed up, most from around our area in northwestern Wisconsin. They did this year after year. A few of the retired ones followed the circuit in their RVs through most of the season.
We saw a lot of license plates from very distant states.
The number of people those stands hold boggles the mind the first time you see it. I don’t know about 30% but 20%+ sure doesn’t seem far fetched to me.