“This is a unique issue relating to Route 9, which transverses most of the eastern seaboard of the US.”
As I and Yser… have pointed out, is there anything that Rav Ahrona has written regarding this unique psak?
Again, this situation is not the first klal Yisrael has had, and Gadolei haPoskim have written their responsa on these issues.
Bnei Brak and Jerusalem would have the same issue with any street connecting to the Kvish/Highway.
I recall Rav Moshe mentioning something in regards to the roads leading to the train tracks in Europe, where between all stops there were thousands of passengers..