The stupidest or most idiotic person in a particular village, as elected by the local populace. The kind who would steal all the sugar from an overturned lorry and go door-to-door trying to sell it.
"Read your town charter, boy. 'If foodstuff should touch the ground, that foodstuff should be turned over to the village idiot.' Since I don't see him around, start shoveling!"
-Homer Simpson
On some highways the far left lane is designated for passing only. (Typically with signs that read "Left Lane For Passing Only") Left lane idiots are people who stay in the left lane, even though they're not passing anyone.
I got stuck behind a left lane idiot and a slow poke in the middle lane for twentymiles.