an unspoken rule that whatever happens on a roadtrip is not repeated to anyone except those involved in the roadtrip.
Marc could not tell Paul's wife what happened on the way to New York because of the code of the road.
the rule that every driver on earth believes that anyone driving slower than they are is an idiot and those driving faster must be assholes.
Look at this idiot driving 50. Holy shit! Did you see that asshole?!?
The unwritten rule in which a hitch-hiker is obligated to give oral pleasure to the kind person who picked them up
I picked up this old lady on my way to the west. God bless the Code of the Road