laskern:t
“There is a big argument whether Ocean Parkway is a reshus horabim min hatorah, if cars are counted with people or it is a separate reshus, houses around, intersecting roads or traffic lights diminish the reshus for pelatyeh gedolyeh.”
Ocean Parkway is not mentioned once in Igros Moshe. It simply never factors in Rav Moshe’s chidushim in eruvin.
However, Rav Moshe does count cars (although most poskim maintain otherwise). I don’t know what you mean regarding platya, Ocean Parkway is definitely not a platya, maybe its a sratya. In any case, Brooklyn is encompassed by mechitzos on three sides.