How to Defend Against Zombies

I've been thinking about how a small community, such as the one seen in season 3 of The Walking Dead, should defend itself against the zombie threat. It's not a simple problem; in the film 28 Weeks Later, we see a well-equipped defense plan fail catastrophically.

To begin with, I think it is foolish to rely on any one mechanism. Any system can fail; we aren't omniscient. It is therefore important to have defense in depth -- multiple levels of (quite different) protection, so no one system has to work perfectly.

What I have in mind are four increasingly fine-grained levels of defense.

At the top is a town guard, responsible for protecting the entire community. They are organized full-timers responsible for securing the perimeter. They set up barriers; they patrol the surrounding area; they stand guard. They also make sure that anyone entering isn't likely to be infected. And finally, they have a well-protected command center that can communicate with other defense elements and coordinate a response if things go badly wrong.

The next level down is something like a very hard-core neighborhood watch, responsible for protecting smaller areas. Their mission is containing the problem if it is already inside the town and mounting an organized response. They might have alarm systems, barriers that can be moved into place to seal off the neighborhood, and specific plans for an armed response if the infected are already inside. They also have a means of communicating with the command center mentioned above, probably using handheld radios.

The third level of defense is at the household level. The goal here is to ensure that for most people, getting indoors and securing the entrances is realistically effective. That way, non-combatants can get out of the way, to safety. Most people would be highly motivated to do this, but many would benefit from at least some advice and some might need actual assistance. (This would not be optional, since a poorly-protected household is a potential source of more walkers, and as such is a danger to others.)

Finally, at the most fine-grained level, would be individual defense. It would be enormously useful if most people were not simply easy meat for the walkers, but could offer credible resistance at least one-on-one. To that end, make sure that all able-bodied adults have basic training in how to fight a walker, and encourage them to keep a weapon (a club or hatchet, say) handy.

Together, these four telescoping levels of protection keep out the walkers if possible, and enable the community to resist tenaciously if they have already gotten in.