CONFEED-ENETEAE”
barriers, and the small likelihood that the highway system can be measurably improved
during the time period considered in this appendix, it would seem that the feasibility of
mass evacuation of large targets is highly questionable. Some small inland cities, such
as Dayton, may be in a position to consider this tactic along with the other passive moves
open to them.
i
MASS EVACUATION TO EXISTING SHELTER IN SMALLER TOWNS AND FARMS
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Determining Feasibility
It has been suggested that residents of critical targets might evacuate and seek shelter
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in the basements and cellars of houses well outside the target area.
To test the feasibility
of such a tactic an area of approximately 8400 sq miles, including Washington and Baltimore, was inspected.
This area was bounded on the north by the Pennsylvania state line,
on the east by Chesapeake Bay, on the west by a straight line drawn to include Hagerstown, Md., and Warrenton, Va., and on the south by a straight line extending west from
Smith Point, about 20 miles north of Richmond. The area northeast of Baltimore was
not included, owing to the proximity of the Wilmington, Lancaster, and York targets.
The population of this area is 3.3 million, of whom 2.7 million live in the twocritical
targets. Of the remaining 0.6 million, 134,000 live in small towns that are not part of the
target complex, an estimated 157,000 live on farms, and the rest live in suburbs adjacent
to the targets.
Below-Grade Shelter Available. In the absence of an actual survey it is assumed that
50 percent of the dwellings might have below-grade shelter equivalent to 750 sq ft.* On
this basis the townsalone could provide approximately 5sq ft of shelter for each inhabitant
of the two critical targets.| The towns and farm buildings together could perhaps provide
10.7 sq ft of below-grade shelter for each evacuee. These figures exceed the minimum of
5 sq ft per person recommended by the ropa.
Times Required. The numberoftraffic lanes leading from Baltimore and Washington
to open country or smaller towns is 28 and 26 respectively.
(These numbers do not include
the lanes that lead only from Baltimore to Washington, the lanes that go from Baltimore
northeast, or the lanes that lead only to the cities’ suburbs.) Using the figure of 1000
vehicles per lane per hour, at least 9.5 and 13 hr, respectively, would be required to empty
the target areas. An additional 2 hr would be required for the last vehicle to reach the
median town, 70 miles distant. These times are well in excess of the 0.5 to 1.0 hr of warning
time predicted for the two targets.
The three largest towns in the evacuation area were considered in detail. Table 6
showstheir population, the below-grade shelter space available after the needs of the local
residents have been subtracted, the number of evacuees who could be sheltered at the rate
\
*Along the Bay and in the Eastern Shore region below-grade shelter is negligible because of the high
water table. It is estimated that in older inland towns and on farmsup to 75 percent of the dwellings may
havecellars, but many of these would be ‘root cellars’’ with far less than 750 sq ft. However, many farms
have “bank barns,’’ where one-half the structure is partly below grade. Many newer dwellings (up to
80 percent in someareas) are built on concrete slabs and have no available shelter. As a reasonably good
over-all estimate, 50 percent was selected. (Information provided the author by the Maryland Civil Defense
Administration.)
{This figure includes total basement space. it is presumed that in the event of emergency any basement space presently used for storage would be cleared.
ORO—R-17 (App B)
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