Social distance has long been a goal of American settlement patterns; the suburbs were built on separation and segregation. Today, with a new set of problems pressing on our metropolitan areas, Americans still turn to separation as a solution.

Suburbanization has not meant a lessening of segregation, but only a redistribution of the urban patterns of discrimination. Gated communities are a microcosm of the larger spatial pattern of segmentation and separation. In the suburbs, gates are the logical extension of the original suburban drive. In the city, gates and barricades are sometimes called "cul-de-sac-ization," a term that clearly reflects the design goal to create out of the existing urban grid a street pattern as close to the suburbs as possible.

Exclusion imposes social costs on those left outside. It reduces the number of public spaces that all can share, and thus the contacts that people from different socioeconomic groups might otherwise have with each other. The growing divisions between city and suburb and rich and poor are creating new patterns which reinforce the costs that isolation and exclusion impose on some at the same time that they benefit others. Even where the dividing lines are not clearly ones of wealth, this pattern of fragmentation affects us all.

Some argue that gates and barricades are unfortunate but necessary. They feel that such measures are the only way for beleaguered neighborhoods to reclaim their streets and for better-off neighborhoods to protect themselves in the future. But are these expectations realistic? In the course of our field work, we interviewed local law enforcement and analyzed local studies of streets closures. We found no firm evidence of any general permanent reductions of crime in fully gated communities or in the barricaded streets of the Security Zone. In part, this is because most evidence is anecdotal, and it varies greatly. Some Security Zone communities report drops in crime after streets are closed. Some report only temporary drops, and some no change at all. And still other places have removed barricades as failures, such as in Sepulveda, California, where local gangs used the maze of blocked streets to evade police and control their turf.

In addition to this wide variation in the reported effects of street closures, there is the problem that many available reports simply give "before and after" crime rates. Because such information often does not include comparisons with the crime rate in the overall area, or with longer-term trends, it is hard to conclude what effect the barricades themselves really had.

Gates and fences are not impenetrable to serious criminals, and they do nothing to reduce crime arising from residents. They do not necessarily protect, and they often cause dissension and controversy.

Efforts of neighborhoods to take back their streets are inspirational and sorely needed. That many are turning to barricades is understandable. But the issues that stimulate gates, walls, and private security stem in part from the inattention we have paid to building communities. Without community, we have no hope of solving our social problems, or ever really gaining control of our deteriorated neighborhoods. Physical design does have a place in building community and fighting crime; our choices in architecture, street layout, landscaping and design, and lighting all can help neighborhoods to protect themselves from threats. But these physical design choices are best used to facilitate and encourage social, community responses. Ever since Jane Jacobs, urban designers and planners have recognized that "eyes on the street" are basic defenses against crime. This is the social control of a tightly-knit community. Overall, such socially-based mechanisms are more effective than additional hardware like gates.

We must also remember that the reasons for gating are not always entirely, or even primarily, the laudable reasons of crime and traffic control. Hopes of rising property values, the lure of prestige, and even the desire to build barriers against a poorer neighborhood or one of different race are also common reasons behind gated communities.