Gandalf "You Shall Not Pass" Car Sticker
Gandalf and the Lord of the Rings may be fading back again out of popular culture but they are NOT forgotten! The movies brought them back into the public's consciousness and one of the classic scenes was Gandalf stopping the Balrog at the bridge, telling him, "You shall not pass!".
Likewise, tell those people passing you what's up. But if you need this, why are you in the slow lane getting passed? Ah well, in any case, this thing is funny and will remind people of the awesomeness of Gandalf. Maybe they'll be thinking of Gandalf getting pulled off the bridge saying, "Fly, you fools!".