Concentrated defense

A concentrated defense relies on dozens of active survivors. If there are enough survivors to maintain barricades, manage revive points, and scout for zombie activity 24/7, a suburb would become indestructable. Basically, take the Urban Warfare Doctrine, and multiply by a thousand, then fit it into a Trp rich 10x10 block. Obviously this tactic needs massive survivor cooperation and coordination, but the tactic is rather simple.