She's been a phantasm since I was a kid, and I finally found out about the mysterious Mud Flap Girl. I always saw her on mud flaps or in front of big trucks and always wondered where she was from. She was apparently designed in the 70's by Bill Zinda, owner of Wiz Enterprises in Long Beach, California. The model was Leta Laroe, a famous stripper.
In the name of political correctness , she will probably disappear one day (a sad day for sure). The Arizona State (U.S.A.) already tried to pass some legislation about it (article 1, article 2).