Is that counting the cars on blocks in the yard or just the ones in the street?
"How much traffic & parking congestion could actually result from 4 homes?"
In a neighborhood I lived in about 10 years ago, we had an owner who decided to rent rooms. I've counted as many as 12 cars at that house on too regular a basis to be 'entertaining friends'.
There are a couple of known "sales" of H4H houses that went to crack dealers.
Perhaps they could specify to hold the crack, just provide cocaine, pot, oxycontin, Special K, Prince Valium, etc., and none of them other "street" drugs?
And maybe if any Kennedys are in the area, Ambien.