A possible underground Zombie Bunker complex, complete with watch tower for 360 degree observation.
As someone who lives in Australia, the idea of using the same principle that is used for bushfire bunkers here, for Zombie bunkers in the case of an apocalypse has occurred to me. If news of an impending Zombie horde or infection is received, a family could very easily retire to an already fully stocked home bunker, theoretically remaining there until the threat has passed or help arrives. With sufficient food, water, medical supplies, (and in the case of a zombie virus) breathable air, the occupants could survive almost indefinitely in a safe and relatively secure environment. Depending on the wealth of the family in question these bunkers could be anything from small, one room reinforced concrete sheds, to large intricate underground complexes designed to house a number of families, or even a small community.
However, if the latter option is undertaken, extremely cautious screening procedures would have to be followed regarding who is allowed into the bunker. If an infected person, who may not yet show any alarming symptoms, was allowed into this sealed environment, everybody inside would be at extreme risk. The infection (if the zombie threat is of an infectious nature) could spread rapidly to all those in such close contact, and the facility would be entirely compromised.
A possible solution could be a containment area which all new, or even ALL, arrivals must be kept, under observation, for a set period of time before admittance to the main complex. This however would require some sort of 'bunker authority' and security detail, which must be properly administered so that the situation be prevented from turning into a chaotic and paranoid anarchy.
Communication would be key to knowing how the zombie situation stands outside the confines of the bunker. Channels such as satellite phone, internet, and media could be used to communicate with the outside world, but in the event of a total zombie apocalypse, these services would most likely be rendered useless, as all infrastructure would break down. In these cases two way radios and other independent forms of communication would have to be relied upon. Perhaps a whole series of these bunkers could be connected by a network of radios, or even by a private, fiber optic cable running between them. In the event of a total Zombie apocalypse, communication with survivors in other such bunkers would be vital to the morale of the occupants of any given facility. On NO account should 'messengers' be sent outside the walls of the bunker except in EXTREME circumstances!
If the Zombie virus or infection could be transmitted through the air, a specially sealed and self-reliant ventilation system would also need to be installed, so that occupants have fresh, and uninfected, air to breath. This would have to be done without compromising the security of the structure, and is obviously not the sort of thing that should be undertaken by someone with inadequate skills, ideally a specialized contractor would be commissioned.
Maybe entire neighbourhoods should begin planning for the construction of such a facility, or begin petitioning local government to install these types of safeguards against possible apocalypses, zombie or otherwise. Community groups could begin to meet and devise contingency plans for what would happen in the event of a zombie infection, planning out safe houses, supply sources, and people's roles (crowd control, maintenance, supply administration, and security). With enough organisation, funding, and motivation, these safe facilities could become a reality for use if ever a zombie threat arrives.