You Shall Not Pass Decal
YOU SHALL NOT PASS says Gandalf! And when Gandalf declares something, it is so! Show off your nerdling spirit and keep those trolling cars trying to pass you from doing so with the magical forcefield Gandalf creates around you vehicle, keeping them from speeding past you like Balrog the demon! If they do manage to do so, though, you might want to hide your face as they speed past, laughing at you.