I've read that book at least 15 times and it still scares the hell outa me when I read it.
If you're interested, buy Alas Babylon here.
This is very much like Alas, Babylon. I haven't read it in over 40 years, but if I recall that was nuclear war which effected certain areas more than others due to fallout etc. The infrastructure wasn't as compromised as completely as it was in One Second After.