In the aftermath of 11 September 2001, many institutions will conduct thorough security reviews with a view to toughening security-related design and construction standards. Because of the confusion and disarray that understandably prevailed inside and near the World Trade Center and the Pentagon following the attacks, organizations will also review and improve emergency procedures. They will evaluate annunciation systems, evacuation plans, chains of command, preparedness, and other aspects of disaster response. These steps should help to improve conditions in future emergencies, even if it is difficult to imagine orderly or controlled responses to destruction on the scale witnessed in New York and Washington.

Buildings at the limit
However, when it comes to beefing up the blast-resistance of exterior walls and glazing systems or taking other costly approaches to making buildings tougher, skepticism is in order. Even if we could afford to do so, is it practical to design buildings to withstand warlike assaults when they are meant for peacetime civilian purposes? The state of the art in security-related design and construction, at least when applied to more or less quotidian buildings, has already been pushed just about as far as it is reasonable to go.

Threats from the skies-and others on the scale of warfare-will have to be handled by other means. The required measures may have something to do with building design and construction, insofar as airport access control and tighter restrictions on circulation are concerned. But generally speaking, architecture and design can do little to thwart military-style threats, and it is misguided to place too much stock in "target-hardening" as an approach for buildings in America's urban centers.

The role of urban design
Urban planning and design, however, do have potential to aid in the quest for improving civil security because they engage directly such questions as how to design protected urban enclaves and security control zones or where best to situate mass transit facilities. Of at least equal importance: Good urban design can help to foster vigilant, proprietary interest in public and private spaces, which is essential for secure environments.

Given the likelihood-or at least the specter-of protracted threats, most organizations will probably find it easiest to implement procedural changes. Thus, access to many types of buildings will become far more restricted than has been the case. The "envelope of concern" will now extend to surrounding sidewalks, parking areas, and streets. Airport-style identity checks and searches are likely to become routine at many entrances and will probably be rigorous, at least for a time.

People parking near some facilities and even those loitering on nearby sidewalks may be challenged. Such steps will of course do nothing to reduce the risk of airborne attack, but they are steps that can be taken, and they may reduce vulnerability to some forms of assault.

Protected zones
Over time, however, "protected urban enclaves" and "urban security control zones" could emerge. These are defined center-city areas where all pedestrians and vehicles are monitored and possibly inspected as they enter the zone. As in classic protected places, sentries may challenge persons before granting access. We already know the face of contemporary cities in places at war (Londonderry, Jerusalem, Colombo, Bogota): Entry points are few, waiting lines are long, inspections and interrogations can be tough, and the sentries bear arms. In today's terms, in the U.S., interviews and searches would probably be conducted by well-mannered private security guards wearing blazers and posted at key urban portals rather than solely at entries to individual buildings.

Permits could be required for regular access to such urban zones. To obtain passes, visitors will have to state and prove their business. Among many other European cities seeking to reduce vehicle parking and congestion in central historic areas, Rome and Paris already employ approaches along these lines that could be adapted to serve security purposes. In any case, one can easily imagine more and larger urban districts, where all persons seeking to enter will be required to present full identification and submit to search.

The perimeters and interiors of such control zones lend themselves to standard patrol and policing methods. More sophisticated surveillance and monitoring techniques could also be employed. Special motion-triggered security cameras, for example, have been used effectively in areas of London. The essential conditions for an urban control zone have already been established around the White House and Lafayette Square for nearly a decade, and that zone is now likely to be expanded. Similar measures are also more or less permanently in place around the Elyseés Palace, as well as near the adjacent Paris embassies of the United States and the United Kingdom.

New design approaches
Zones of this kind will probably continue to develop and expand in the world's major cities. Seats of political power, government agencies, parliamentary buildings, central police agencies, foreign embassies, and public institutions are likely to concentrate in urban control zones and protected enclaves. Large commercial and office establishments may also be there. If such areas take on some of the characteristics of protected places from other cultures or other eras in history-such as the walled portions of Europe's medieval cities-they will also require new design approaches and new techniques.

The public purpose is to maintain as much as possible in the way of openness and freedom of movement, without foregoing amenity and appeal, while rendering urban settings less vulnerable to attack, easier to guard, and safer. Short of imposing martial law or embracing a full-blown police state, there are few other means by which we can try to cope with-if not always deter-the horrors that now appear more likely to be visited upon civil society.

Copyright 2001 The American Institute of Architects. All rights reserved.