Two pieces of black tarmac walk into a pub, and say to the barman, "oi
barman! we're two peices of black tarmac and we're hard as nails, give
us some whisky or we'll punch you one!" They take their whisky and go
sit down and talk really loudly about who they've beaten up. Suddenly
the door opens, and in walks a piece of red tarmac. The two pieces of
black tarmac look at each other, leap in to each others arms and run
screaming into the back room to hide under the pool table. When the red
tarmacs gone the barman goes in to find them cowering under the table,
and he say " i thought you two were two pieces of black tarmac, hard as
nails? that red tarmacs just walked in and you've **** yourselves" and
the black tarmac says yeah but we dont mess with him, he's a cyclepath!"

this must be something from a different state or country tha I am
from... because I just dont get the punchline at all...

Cyclepath - Physcopath.

Tarmac is a road covering