Curious Louisville: Who Cleans Up Graffiti On The Backs Of Freeway Signs? Whatever it is, it's part of your morning commute. "Every morning when I commute to work, no matter which way I go, I started to see more and more graffiti on the back of the signs," Joe Sullivan reported. So Joe asked Curious Louisville, who's cleaning that up? And the answer takes us on a commute of our own, through both sides of the art/vandalism debate.