Like A C4 Explosive that you would have to sacrifice yourself to like blow a hole in the road. Slowing down the zombies somewhat?
EDIT: I'll Put it in thanks for the idea. Ill put you in the credits.
Haha I'll add cover to the point that it still looks realistic. I don't want tons of bookshelves, vending machines, And couches all over the place. Anyways i know i need to find a way for the survivors to have cover since fast zombie is OP.