I think the difficulties of getting out of NYC illustrate the importance of being ready to move NOW. I don't want to live out of my BOB and hope I never need to do so, but it's there, ready right now, and I can leave and count of it for a few days. Being ready to move allows you to do it, right now, not wait and pack.

If you can do it carrying your BOB, that allows you to be more flexible in your choice of transportation. If need be, I am prepared to grab any form of mass transit that will take me out of NYC and immediate danger, or huff it. Huffing it maybe slower, but it can work. Jumping on a subway and then walking might be an option.

In addition, you need some idea about where you can go. What are the likely disasters? What risks does each present? What are your options for a safe haven? Once you have that figured out, think about how can you get to your possible safe havens. A car and metro-north railroad are great options for me, depending on timing. If everyone is leaving or wants to leave, I know the car is not as good an option. Metro-north should be a good option. If it is not, the subway, Amtrak and PATH trains become things I consider. Bugging in is always an option.