Mufflers have been required by some sanctioning bodies to keep the neighbors happy. Having a race track in an urban environment is tough. Frequently the track is built in the boonies and the houses show up later.
San Fernando drag strip, Lions, Irwindale all had noise problems. I'm surprised Pomona still has the Winternationals and Auto Club Finals. Even with late start times and early shutdown. There are very expensive homes all around the track.
As a kid I could hear San Fernando from 4 miles away on Sunday morning.
Bonneville and El Mirage certainly don't have anyone living close.
Maxton is rural, but only about 3 miles from town as the noise flies.
It only takes one politically well connected #*$@&$ to screw things up.