This project was stuck in development hell forever.  At one point it was going to be Kevin Smith's big chance to prove he could direct a serious mainstream blockbuster.  (Kevin got cold feet and realized he probably would not end up proving anything of the kind.)  Years later, the end result of all that foofaraw is... a Seth Rogen comedy.  Apparently the idea of a guy who drives around in a gun-equipped car is too weird to make a serious movie about... that's reserved for guys who dress as bats or who turn green and bloated when you hit them.