I don't know what it's like in you people's parts of the country, but if there's ever a mass evacuation in my area NY/NJ/PA, no one is going anywhere. A single car being in an accident causes a massive traffic jam. Really need to get away from any urban center.
Can you imagine?
My plan is to form a group of people in PA and should the need ever happen (i.e. floods on the coast, NYC getting bombed, etc.), we all commit to blowing up the bridges that come into PA.