Ce CONTIDENTTiet~ A final limitation of a national underground shelter schemeis construction time. The new highway program will add heavy requirements for steel and cement to already high boom-period demands. During the time required to construct undergroundshelters on a wide scale, reliance must necessarily be placed on alternative measures. ESSENTIAL CHARACTERISTICS OF AN UNDERGROUND SHELTER PLAN It would appear that a detailed study of reduction of vulnerability such as that recently prepared for the Milwaukee Metropolitan area** might provide a general framework for the description or detailing of a metropolitan shelter plan. The Milwaukee study was divided into three major parts: preventing further increase in the vulnerability of the central area, aiding new growth to locate in the suburbs, and reducing existing vulnerability in the central area. The problem in a program of construction of new undergroundshelters, however, is not one of reducing the vulnerability of an existing and growing target but rather one of designing from the ground up a new target system that will have the lowest possible vulnerability to air attack. Thus the most important single aspect of a metropolitan shelter plan is the new target system it proposes. How can this target system be made least, vulnerable within the bounds of economic, physical, and political feasibility? The design objective is of course maximum survival at minimum cost. Considered as a theoretical design problem, assuming raw land, this objective would require finding the most efficient size, shape, design, mechanical equipment, and materials and methods of construction for a single shelter structure, and then spacing duplicates of such a structure pal prerran renateesglapeintne teininsaira Mir inreiars chee» ciate, ig at uniform intervals throughout the target area. The problem is reduced to a practical basis by adding the requirement that working and living places be located near the shelters and then proceeding to analyze the degree to which working andliving spaces can be moved, over the period of years needed to carry out the shelter program, to conform to desirable spacing of shelters. This is primarily a matter of economic feasibility, tested within the framework of a comprehensive regional plan for future physical development of the metropolitan target area. A metropolitan shelter plan should be based on a geographical pattern of shelters incorporating the maximum dispersion possible. Since shelter location must be controlled by the location of daily activities, the maximum dispersion will depend on the degree of dispersion economically feasible for daily activities. This factor should be expressed in terms of the minimum level of activity or concentration that must be maintained in the central area to preserve the essential nature and inherent advantages of a metropolitan complex. It should also be expressed in terms of the maximum levelof activity or conges- tion for which shelters will be provided, both in the central area and in outlying areas. Local and perhaps federal agencies must decide which of the existing activities in the concentrated central area will be provided undergroundshelter under the national program. All activities in the congested area should be officially informed as to whether they will receive undergroundshelter within the congested area or in a less congested outlying area. a eR rNEET yee ee ee ee ats pe Poor Next it should be decided whether activities requiring central locations and due to be provided central shelter are suitably distributed within the central area, or whether some shifts, perhaps into buildings to be vacated by activities not requiring central locations, would be desirable. Concurrently, work should be underway to determine general locations in the outer portions of the metropolitan target zone where activities eventually to be displaced from the center could settle. Where needed, new high-speed freeways . should be planned to connect the proposed dispersed development locations with one another and with the centralcity. ' pa : | 84 ORO—R—17 (App B)