Black Horse Pike runs from AC to the Walt Whitman bridge and is Rt. 322(there is a White Horse Pike also that leads you to Brigantine and the north part of AC. It also has low lying areas that go over water). I'm guessing the part that buckled is right before you enter AC it's a small causway. If this is the case, this eliminates one major route into AC and it's the most used route. As for Avalon, it's a very rich shore town south of Sea Isle City. There is a low lying bridge into the town but there is also a bridge that is pretty high and that is the one leading to Sea Isle. I believe there is another from the main land and another small one into Stone Harbor
Ah. OK. That's why the Pike is so important. The local Philly station showed it buckled and unusable in one stretch, but I don't know where. If I see it again, I'll let you know.
Do these coastal towns have older roads and bridges in general?