Graffiti on street billboards get great visibility. Billboards on freeways are scarce but are super visible due to the bad traffic conditions in Los Angeles.
BWS - 10 Freeway Downtown Los Angeles
Dr Sex, Shatr, Eleven UW - Downtown Los Angeles
Dr Sex, Shatr, Eleven UW (zoom)
FTW - 10 Los Angeles Freeway
FTW Reclaim buffed billboard