Text

Public Version of Seabrook Station Evacuation Analysis, Final Rept,Estimate of Evacuation Times, Prepared for FEMA
	ML19345C616
Person / Time
Site:	Seabrook
Issue date:	08/31/1980
From:	Herald W, Kanen A, Kulash W; PLANNING RESEARCH CORP.
To:	;
Shared Package
ML19345C615	List: ML19345C616; ML19345C619; ML19345C819;
References
	NUDOCS 8012080007
	Download: ML19345C616 (92)
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$,$h ?]hy&Of!i 'c <!vs SEABRCCK STATICN EVACI.'ATICN ANALYSIS FINAL REPCRT ESTI!! ATE OF EVACUATICN TIMES Prepared For FECERAL EMERGE::CY MANAGEMENT AGENCY 4

Prepared 3y ALAN M. VCC?liEES & ASSCC AH S A Civisien cf ??C ?lanning & Economics 7798 Cid Springh.use Road McLean, Virginia 22102 Projec- Staff:

Andrew Kanen, Prcject Manager, Alan M. Voorhees & Asscciates Walter Kulash, Principal Engineer, Alan M. 7corhees & Asscciates William Herald, Senicr Planner, Alan M. Vcorhees & Asscciates iL't? L)E i

-dt*tY 1980 limo::AL PRI'/ACY INF0FdATION

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ACKNOWLEDGEMENTS

-The authors gratefully acknowledge the assistance of New Hampshire officials,

.who furnished background materials and coordinated an. intensive schedule of local meetings:

o - Eileen Foley, Director of Civil Defense e 'Wes Williams, New Hampshire Civil Defense Agency o Kenneth Field, New Hampshire Civil Defense Agency o -Michael Nawoj, New Hampshire Civil Defense Agency o James Saggiotes, New Hampshire Civil Defense Agency o Robert Lee, Department of Public Worxs and Highways Officials frem Towns in the study area were invariably helpful and coop-erstive and furnished valuable insight into the state of local preparedness.

hese officials and their Towns included:

o Lester Blackwell, Exeter o Everett Stone, East Kingston o Kenneth Fernal, Greenland o John Tanzer, Ha=pton o Laurence Middlemiss, Kingston o Donald Hannon, Newton a Vincent Scagliotti, North Hampton o' Harold Good, Portsmouth o Edward Meany, Rye o Frank Palazzo, Seabrcok o John Hutton, Stratham o John Gamble, South Hampton John DeVincentis, James MacDonald, and Mark Strum of Yankee Atomic Pcwer Company provided results of surveys made in the Seabrook area.

Robert Holzheimer of HMM Associates provided aerial photcgraphy and other backgrsund information for the beach area.

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3 TABLE CF CCNTENTS Chaoter Pace I. INTRCCUCTICN . . . . . . . . . . . . . . . . . . . . . 1

. Study Cbjectives . . . . . . . . . . . . . . . . . 1 Location of the Seabrook Station . . . . . . . . . 1 Background and Chronology . . . . . . . . . . . . 1 4 Other Studies of Evacuation Times . . . . . . . . 3 Local Preparedness and Evacuation Planning . . . . 3 The Emergency Planning Zone (EPZ) Boundary . . .. 4 1- Senmary of Estimating Techniques . . . . . . . . . 4 Smnmry of Evacuation Times . . . . . . . . . .. 5 Issues Related to Evacuation Time Estimates . . . 7 Reccmmendations . . . . . . . . . . . . . . . . . S

!. CHARACTERISTICS CF THE SEABRCCK STATION VICINITY , . . 9 Highway System in the Seabrcok Station Vicinity . 9 Existing Traffic volumes . . . . . . . . . . . . . 9 Other Transportatien Facilities in the Seabrook Station Area . . . . . . . . . . . . . . . . . . . 11 Special Facilities in the Seabrook Statien EPZ . . 11 Governmental Jurisdictions . . . . . . . . . . . . 13

!!!. THE IMERGE' ICY PLA .'dI!!G 20:I2 FCR SEASKCCK STATION . . . 15 General Guidelines for Cefining the E=ergency Planning zone (EPZ) . . . . . . . . . . . . . . . 15 The EP2 Boundary for the Seabrook Station . . . . 15 Criteria for Defining Sectors Within the EPZ . . . 16 Selective Evacuation Sectors for the Seabrook Station . . .. . . . . . . . . . . . . . . . . . 19 Sector 1: 1-Mile Radius frem the Seabrook Station . . . . . . . . . . . . . . . . . . . 19 Sectors 2 and 3: 2-5 Miles from the Seabrook Station . . . . . . . . . . . . . . . . . . . 21 Sectors 4 and 5: 5-10 Miles from the Sea-brcok Station . . . . . . . . . . . . . . . . 21 Inclusion of the City of Portsmouth . . . . . . . 22 IV. PCPULATICN CF SE SEABRCCK STATICN EPZ . . . . . . . . 23 Total Population Characteristics . . . . .. . . . 23 Seasonal and Transient Population . . . . . . 23 Automobile ~ Ownership . . . . . . . . . . . . . . . 25 Population Segments as Defined for Evacuation Analysis . . . . . . . . . . . . . . . . . . . . . 26 i

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a* ' .e TABLE CF CCNTENTS (Continued)

Chapter, Pace

. . . .. 29 V. THE EVACUATION SEQUENCE FOR SEVRCCK STATION

' General Concept of Evacuation . . .. .. . . . . 29 30 Possible dvacuation Time Periods . . . . . ... .

Nighttime Evacuation .. . . . ... .. . . 10 Daytime on a Summer Weekend (" Summer Sunday" Case) . . . .. . . . .. . . .. . . . ...

31-Daytime / Weekday Evacuation (" Winter Weekday" 31 Case) . . . . . . . . . . . . . . . . . ...

31 Critical Time Periods . . . . . .. . . .. .

Pcpulation Segments to be Evacuated . .. . . .. 32 i

Fraily Units . . . .. . . . . . . . . .. . 32 Evacuation Action Steps . . . . . ... . . . .. 33 Public Agency and Private Steps . . . . . .. 33 Evacuation of Auto owning Pcpulation . . . .. . . 35 Receive Broadcast Information . . . . . . .. 35 Leave Place of Work . ... . . . .. . . .. 35 Work-to-Heme Travel . ... . . . . . . ... 36 epare for Evacuating Ecce . . . . . . . . . 36 Travel Out of the EPZ . . . . . . . . ... . 37 Evacuation of Schcol Population . .. . . . .. . 38 Receive 3rcadcast Information . .. . .. . . 38 Evacuate School Population in Buses . . . .. 38 Non-Auto Cwning Households . . . . . . . . . . . . 38 Receive Broadcast Information . . . . . . .. 38 Prepare for Evacuating Ecme . .. . .. . . . 39 Assemble at Collection Points . . . . . . .. 39 Evacuate Non-Auto Owning Households in Buses. 39 i

Population in Institutions . .. . . . . . . . . . 4C Receive Broadcast Information.. . . .. . . 40 Mobilize Population . . .. . . .. . . . . . 40 Evacuate Institutional Population in Buses or Special Vehicles . . .. . . . .. . .. . . 40 Summary of Evacuation Process . . .. . . . ... 41 VI. EVACUATICN RCUTES . .. . . . .. . . . . . . . . . .. 43 General Strategy of Evacuation Routing . . . . .. 43

- . Road Network for vehicle Evacuation . . . . . . . 45 Forecasting Evacuation Traffic . . ... . .. . . 47 Individual Evacuation Routes . . . . .. . . . . . 49 Performance of the Evacuation Traffic System . .. 53 11

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y 4 TABLE OF CONTENTS (Continued) i Chapter Page VII.

SUMMARY

OF EVACUATICN TIME ESTIMATES . . . . . . . . .- 55

- Method for Estimating Evacuation Times . . . . . . 55 Population Segments . . . . . . . . . .. . . 55

' Time Periods . . . . . . . . . . . . . . . . 55 Action Steps . ... . . . . . . . . . . . . 55 Time Required for a Series of Action Steps . 56 Assignment of the Traffic to the Evacuation Routes . . . . ... . . . . . . . . . . . . . 56 Evacuation Times for Case A: Summer St.nday . . . -55 Foz=tation of Traffic Congestion . . . . . . . 38 Extent of Traffic Congestion . . . . . . . . 59

Traffic Congestion and Driver Behavior . . . 63 i Evacuation Times for Case 3: Winter. Weekday . . . 66 Traffic Congestion in a Winter Weekday i Evacuation . . . . . . . . . . . . . . . . . 66 Evacuation of the School Population . . . . . . . 68 Evacuation of the Non-Auto Cwning Households . . . 68 i Evacuation of the Population in Institutions . . . 69 Selective Evacuation of Areas Within the EPZ . . . 69 5 pact of-15-Minute Notification On Evacuation Times . . . . . .. . . . . . . . . . . . . . . . 71 Impact of Severe Weather on Evacuation Times . . . 72 Su= mary of Evacuation Times . . . . . . . . . . . 72 Problem, Issues and Recen:mendations . . . . . . . 74 Seach Traffic Congestion . . . . . . . . . . 74 l

i Effect_ve Evacuation Planning . . . . . . . . 75 Buses for the Transit-Cependent Population . 76 VIII. VEHIC:.ES AND MANPCWER REQUIRED FCR EVACUATING THE SEABRCCK STATICN EPZ . . . . . . . . . . . . . . . . . 77 Introduction . . . . . . . . . . . . . . . . . . . .77 Vehicle Requirements . . . . . . . . . . . . . . . 77 School Buses . . . . . . . . . . . . . . . . 77 Transit Buses . . . . . . . . . . . . . . . . 78 Ambulances . . . . . . . . . . . . . . . . . 78 1

Traffic Control and Towing vehicles . . . . . 79 Manpower Requirements . . . . . . . . . . . . . . 79-t School Bus, Transit Bus and Ambulance Drivers 79 Traffic Control . . . . . . . . . . . . . . . 79 Tow Truck Cperators . . . . . . . . . . . . . 74 Supervisory and Coordinating Personnel . . . 80 S - ary of vehicle and Manpower Requirements . . . 80 l 1

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TABLE CF CONTENTS (Continued).

Chanter Page

.IX. CCNFIRMATICN CF. EVACUATION . . . . . . . . . . . . . . 92 Confirmation Process . . . . . . . . . . . . . . . 82 Possible Approaches to Confirming the Evacuation of the EPZ . . ... . . . . . . . . . . . . . . . . 82 Recomended Concept.for Confirming Evacuaticn in the Seabrook Station EPZ . . . . . . . . . . . . . 83 r

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LIST OF FIGURES Figure Pace 1 Location of the Sea rook Nuclear Power Station . . . . 2 2 Highway System in the Vicinity of the Seabrook Station. 10

- 3 Other Transportation Facilities in the Vicinity of the Seabrook Station . . . . . . . . . . . . . . . . . . . 12 a

I 4 Local Government Jurisdictions . . . . . . . . . . . . 14 2- 5 . Plu:ne Excesure EPZ Soundary . . . . . . . . . . . . . . 17.

1 6 Selective Evacuation Sectors for the Seahrook Station EPZ . . . . . . . . . . . . . . . . . . . . . . . . . . 20 7 Populatien Segments and Evacuation Sequences . . . . . 34 3 Evacuation Rcuting Strategy . . . . . . . . . . . . . . 44 9 Evacuation Gateways and Capacities . . . . . . . . . . 46 4

10 Evacuatien acutes: Case A, Sc=mer Sunday . . . . . . . 51 11 Evacuation Routes: Case 3, Winter Weekday . . . . . . 52-4 12 Evacuation Times: Case A, Su==er Sunday . . . . . . . 57 13 Traffic Congestion Analysis . . . . . . . . . . . . . 60 14 Traffic Congestion: Case A, Su=mer Sunday . . . . . . 61 15 Evacuation Times: Case B, Winter Weekday . . . . . . . 67 J

16 Selective Evacuation Times. . . . .. . . . . . . . . . 70 1

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LIST CF TABLES Table Page 1 Su:mmary of Evacuation Ti:nes . . . . . . . . . . . . . . . . 6' 2 Governmental Units within the 10-Mile Radius and EPZ of the Seabrook Station . . . . . . . . . . . . . . . . . . 13 3 Total Resident Population of the Seabrook Station EPZ . 24 4 Auto Cwnership in the Seabrook Station EPZ . . . . . . 26 5 Seabrook Station EPZ Population by Segments . . . . . . 28 6 St=snary of Evacuation Action Steps . . . . . . . . . . 42 7 , Evacuation Traffic Forecast . . . . . . . . . . . . . . 40 ,

i 8 Evacuation Tines for Seacrook Station . . . . . . . . . 73 >

9 'Tehicle and Manpower Requirements for Evacuating i Seabrook Statien EPZ . . . . . . . . . . . . . . . . . 31 i

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I. INTRCDUCTICN STUDY C3JECTIVES This report describes the estimation of the time required to evacuate the pcpulation frem about a 10-mile radius of the Seabrook, 'few Hampshire, Nuclear Power Station.

Two cbjectives are served by this analysis:

(1) An independent assessment of evacuation times to serve as an additional viewpoint to the evacuation time estimates developed by the utility.

(2) To further develop a sesadardized approach, to estimating evacuation times, that can be applied to other locations.

CCATICN CF THE SEABRCCK STATION

he Seabreck Station is located on the Atlantic dcastline, in the town of .

Seabrock, New Ha=pshire, 40 miles north of Besten, MA, and 15 miles south of Ports =cuth, NH. The station is 2 miles north of the Massachusetts-New Hampshire State Line. (See Figure 1.)

3ACKORCUND AND CHRCNOLOGY The Seabrock Station is being developed by a consortium of New England utilities, under the leadership of Public Service of New Ha=pshire.

Application for licensing was begun in 1972, and construction started in 1976.

Start-up of the plant, originally planned for 1979, has been delayed by enviren= ental opposition, court actions and work stoppages. *he currently projected start-up date is 1983.

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OTHER STUDIES OF EVACUATICN TIMES

! An evacuation time estimate for the 10-mile radius of the plant is in the process of being prapared by New Hampshire Public Service.1/ A preliminary i estimate of slightly over 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months for the " clear time" for the pcpuistion evacuating in private vehicles has been =ade. (" Clear time" is deti. sed as the time required for evacuation, given that the population has alrea w received the necessary information.)

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LOCAL PREPAREONESS AND EVACUATION PLANNING .

An evacuation tica esti= ate assumes,that an effective local preparedness plan is in operation. Among the elements of such a local preparedness plan, seme of the =cre critical elements are identified:

o Cetailed evacuation olans, addressing notification, routing, manpower and resource requirements, confirmation of evacuation and transportatien of ncn-vehicle cwning population (schools, non-auto owning households and persons in institutions).

o_ Local notificatien crocedures and hardware, including siren, public address and telephone notification, procedures for broadcasting radio and television information.

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o C:==unication within EPZ, and between Seabrook Station, State Civil Defense Agencies and towns, and within towns themselves.

o Local (town) mobilization and decision-making.

o Detailed traffic control clan.

- i o -Securine buses for transporting the school population.

-1/Public Service Company of New Hampshire, Preliminarf Evacuation Clear Time Estimates Fo:- Areas Near Seabrook Station, July 1980.

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o Securine buses or other vehicles for transporting non-auto owning households and persons in institutions.

o Securine ambulances for non-ambulatory populations.

o Receotion centers and procedures for clearing evacuated population through them.

o Manecwer (traffic centrol, supervisory, security emergency services) for conducting the evacuatien.

It is assumed that, by the projected start-up of Seabrock Station in 1993, local preparedness planning will be developed to a level comparable to that now observed at operating plants with similar EPZ pcpulations. In the absence of effective preparedness planning (for exa=ple, failure to secure trar: sit vehicles, ineffective notification, lack of traffic control, etc.) ,

the evacuation time estimates given in this report are invalid.

SE EMERGENCY PIXOCIG ZONE (EP::) 3CL"!CARY The Seabrock Station E=ergency Planning 2cne (EPZ) boundary is defined al= cst entirely along town boundaries. "'he only exceptions are the inclusion of small and lightly populated parts of the Cities of Portsmouth, New Hampshire, and Haverhill, Massachusetts.

SCO!ARY CF ESTIMATING TECHNIQUE 2.e methed used in developing these evacuation ti=e estimates is based on separating the population into segments, according to how they evacuate the area. For each population seg=ent, a series of discrete action steps ,

is identified, and the completien times for each step determined.

These times for ccmpleting each step ata then linked together statis-tically to yield the tttal evacuation time for that population seg=ent.

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The advantage of this methcd is that travel times are estimated for each individual step of the evacuation sequence (for which data is readily available) rather than for the entire evacuation as a single entity (for which data is non-existent) .

Two cases of evacuation ti=e estimates are made: (1) for evacuation during a Su==er Sunday when te=porary (beach; populati,n is greatest, and (2) for s

evacuation on a Winter weekday when schools are in session.

SDDiARY OF EVACUAT CN TLW For the critical time period (Su==er Sunday), the total evacuation ti=e (Table 1) is 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 10 minates. Ti=es are =easured frem the beginning of notification until all population has cleared the EPZ. The critical cc=-

ponent of this ti=e is the evacuation of beach-area traffic; all non-beach areas of the EP: can be cleared in 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months 55 minutes or less.

For the second mest critical ti=e period (Winter weekday), the total evacu-ation time is 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months 40 minutes after start of no?ification.

Su==er Sunday evacuation times by sector range from 5 hcurs 20 minutes to 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 10 minutes after start of notification, depending on ecmbination of sectors considered.

Under severe weather conditions (Winter stor=) the total evacuation time is 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months 30 minutes after start of notification, or 123 percent of the *i-a for a Winter weekday evacuation under nor=al weather conditions.

For the critical time period (Sc=ner Sunday) , notification of the entire population within 15 minutes does not reduce the total evacuation ti=e noticeably. The evacuation ti=e for the Su==er Sunday situation is deter-mined al=op- .otally by the rate at which the beaches can be evacuated; speeding , the notification process, under these circu= stances, simply accelerates the rate at which motorists enter the existing traffic congestion.

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TABLE 1

SUMMARY

OF EV?.CUATION TIMES

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Time 1/ Required ,

To Evacuate All Conditions ~ Pooulation 1

4 Summer Sunday 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 10 minutes Winter Weekday, Normal Weather 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months 40 minutes Winter Weekday, Severe Weather 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months 30 minutes Selective Evacuation, 2-Mile Radius 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months 10 minutes

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' Selective Evacuatio:, 5-Mile Radius 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months 10 =inutes to 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months 40 minutes i

Selective Evacuation, 10-Mile Radius 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months 10 minutes to j 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 10 =inutes l

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- Time measured from beginning of. notification.

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.7 ISSUES RELATED TO EVACUATICN TIMS ESTINATES In estL=ating evacuation times for the Seabrock Station EPZ, several un-resolved issues were encountered:

o Behavioral issues. In a Sum =er Sunday evacuation, a substantial portion of all evacuating population is delayed in traffic cen-gestion. In the beach area, this delay ranges up to a maximum of 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months 15 minutes. Most of the traffic caught in congestion is within 5 miles of the Seabrook Statien, with a substantial

^# '*4 vers portion within direct sight of the plant. The behavio" under these conditions of delay and proximity to the Seahreck Statien can only be guessed. Ecwever, any breakdown in orderly evacuatic.; traffic ficw will result in evacuation times greater than these estimated. For in evacuation in which traffic control is generally ineffective, total evacuation times will range frem

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10 hours1.157407e-4 days 0.00278 hours 1.653439e-5 weeks 3.805e-6 months 30 minutes to 14 hours1.62037e-4 days 0.00389 hours 2.314815e-5 weeks 5.327e-6 months 40 minutes.O o Local preparedness planning. Ivacuation times astinated in this report assume that an effective preparedness plan will be developed by 1983. Hewever, the lack of funds at the iccal level for pre-paredness planning, as well as the shortage of manpower resources (police , etc . ) needed to ecnduct an evacuaticn, raises sc=e concern as to the actual state of p.eparedness by 1983.

o Transit vehicles. The transit-dependent population (i.e. , persens who do not have access to a private vehicle for evacuation) in the Seabrock EPO is substantial, and a siceable fleet of buses would be needed for their evacuation. Arranging for a fleet of this size is a major undertaking, not yet addressed by local plans.

1' / Based on capacity less factors reported in Highway Research Record 4349, Traffic Flow, Capacity and Quality of Service, National Academy of Sciences, 1971, p 41-46.

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o Large traffic volumes on the other primary north-south highways (US 1 and State Route 1A) . The largest component of this traffic is local; i.e., beginning or ending a trip within the Seabrook Station vicinity. The remainder of the traffic is more long distance in nature.

o on arterial streets within the erbanized areas (Newburyport, A=esbury) , daily traffic volumes typical of small urban areas.

o Light volumes on the east-west highways that do not penetrate a =ajor :cwn; for exa=ple, Exeter.

o substantial volumes on east-west highways that penetrate major towns; for example, State Route 51 to F.xeter.

OTHER *3ANS?CRTATICN FACILITIES IN THE SEAEROCK STATION AREA

?.c active rail alignmente run in the north-south directicn thrcugh -he region (Figure 3) .

Some small general aviation airports are located in the region. No scheduled carrier service is operated at these airports. A major military nr base (Pease Air Force Base) is located slightly outside the 10-mile radius of the Seabrook Station.

Several harbor facilities for small ve.4sels are located in the region.

However, no harbor of ce=mercial significance is located within the 10-mile radius of the Seabrook Station.

SPEC!aL FACILITIES IN THE SEABROCK STATICN EPZ Figure 3 summarizes the location of the special facilities in the EPZ. ,

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I Figure 3. Other Transportation Facilities in the Vicinity of Seabrook Station 12

. ,a Because of its location near the Boston urbanized region, the Seabrook EPZ contains only a- limited number of primary-care health facilities, and no specialized or secondary care facilities whatsoever. Thirteen nursing homes are-located in the Seabrook EPZ at the present time.

Major recreational attractions are the series of beach areas and parks, and-the race track.

The Phillips Exeter Academy in Exeter is the only major educational insti-tution in the Seabrock Station EPZ which contains a significant population of resident students.

GOVERNMENTAL JURISDICTIONS j

"..e area, defined by a 10-mile radius frcm the Seabrock Station, includes parts of two states, two counties, and two cities. The area of the Atlantic Ocean within 10 miles of the Seabrock Station is under control of the U.S. Ccast Guard, f

Govern = ental jurisdcietions are shewn on Figure 4.

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~ ' Figure 4. l.ocal Government Jurisdictions 14

III. THE EMERGENCY PLANNING ZCNE FOR SEABRCCK STATICN GENERAL GUIZELINES FOR CEFINING THE EMERGENCY PLANNING ZONE (EPZ)

The Emergency Planning Zone (EPZ) is established by federal regulaticns as a 10-mile radius for the protection of pcpulation frem direct radia-tion exposure.

In adapting this 10-mile radius to any particular site, seme general guidelines are observed:

o the EPZ must include at least the 10-mile radius of the power station.

o The EPZ must be easily identifiable. Rather than strictly folicwing an intangible radius, -he EPZ boundary should fellow natural features (shorelines, streams) , man-made features (highways, railroads) , or governmental bcundaries.

o *he EPZ boundarf should not split major ccherent populations, such as the citias of Haverhill or Portsmourh. Pather , the EPZ boundary should either include er exclude such cencentra-tiens in their entirety.

o The EPZ boundary should be regular and censistent, with support-able reasons for including areas. Evacuation of large popula-tien groups well beyond the 10-mile radius should be avoided.

THE EPZ SOUNDARY FOR THE SEABROCK STATICN Several features of the area around the Seabrcok Station help establish the plu=e exposure EPZ:

15

. p.

i 4 o Cther than the Atlantic shoreline, there are few dcminant

' natural man-made physical features which could serve as portions of an EP: boundary. [

i o There are a number of town boundaries in the area, and a

' streng awareness of tow s as the primary governmental jurisdiction.

j o Two concentrations of population (Haverhill and Portsmouth) are just beycnd the south and north extremities of the EPZ.

j

i In light of these features, an EPZ boundary is proposed (Figure 5) to:

]

o Follow town lines for almost all of the proposed EPZ boundary.

o Include only those portions of the cities of Haverhill and Portsmouth shich are within the 10-mile radius of Seabrook Station.

2e enulting EP _

boundary enccmpaste:s at least the 10-mile radius frem Seabred Station. At seme points, sizable areas beyond a 10-mile radius j are included, particularly along the western border of the EP3. Ecw-I ever, these areas centain negligible population.

I S e preposed EPO boundary falls almost entirely along local government (town or city) lines, and consequently only two such local jurisdic-tions are divided by the EPZ boundary. Table 2 suemarizes local government jurisdictions within the 10-mile radius of the Seabrcok Station and also within the preposed EPZ.

CRITERIA FOR CEFINING SECTCRS WITHIN THE EPZ Federal guidelines call for establishing, within the plume exposure EPZ, ,

a series of sectors as follcws:

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17 l

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TABLE 2 4

I GOVERNMENTAL UNITS WITHIN THE 10-MILE 2 RADIUS AND EP: CF THE SEABRCCK STATICN 1

4

[

PCRTION CF TOTAL

{ LAND AREA WITHIN e

10-MILE RADIUS SEABRCCK OF SEABROCK STATICN EPZ NEW HAMPSHIRE i

, CCUNTIES

. Rockingham part part CITIES

, Portsmouth part part 4

TCWNS Brentwcod part all East Kingston all all Exeter part all Greenland part all

Hampton all all j Hampton Falls all all

- Kensingten all all !

I Kingsten part all l

.Newfields part all Newton part all North Hampten all all Rye part all l

Seabrook all all

South Hrapten all all i Stratham part all i .

E f MASSACHUSETTS CCUNTIES Essex part part t CITIES part

~

Haverhill part Newburyport all all

} TCWNS Amesbury all all

., Merrimac part all Newbury' part all

. Salisbury all all West Newbury part all 18 i I

1 Distance frem Power Definition of Station Sectors 2 miles Two - 180-degree sectors 5 miles Two degree sectors To Boundary of Plume Four degree sectors Exposure EPZ (about 10 miles)

These criteria are guidelines only. Actual sector boundaries depend on the shape of population concentrations and physical features. In particular, it is desirable that sectors not divide contiguous concen-trations of population.

Selective evacuation sectors should also recognize wind patterns, so that areas of high probability of beind downwind frem the power station can be evacuated separately, withcut the need for evacuating in unnecessarily wide area of the total EPZ.

SELECTIVF EVACUATICN SEC"CES FCR THE SEABRCCK STATICN Figure 6 illustrates one posaible division of the Seatrcck Station EPZ into secters for selectivo evacuation. These sectors follow the general guidelines above (2-mile, 5-mile and 10-mile radius frem the Seabrock Station). In general, sector beundaries are defined along tcwn boundaries, se that in any selective evacuation.most towns are evacuated in their entirety. In a few instances, selective evacuation sectors are defined along a major highway.

Sector 1: 2-Mile Radius frem the Seabrock Station The basis for this sector is the 2-mile radius from the Seabrook Station.

The north boundary of this sector is defined by the Hampton Falls town line, except at the eastern extremity, where the populated area of Hampton Beach is included. On the west, Sector 1 is bounded by I-95 (New Hampshire Turnpike). The Seabrook town line is the southern boun-dary of this sector.

19

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4 EVACUATtON SECTOR SELECTIVE EVACUATION SECTOR

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l - ' FigGry6. Selective Evacuation Sectors for the Seabrook Station EPZ 20

f Sector 1 includes most of the town of Seabrock, a small part of Hampten l and that portion of Hampton Falls east of I-95. The dcminant popula-tien feature of Sector 1 is the beach area (Seabrook Beach and Ha=pton Beach).

f l Sectors 2 and 3: 2-5 Miles frem the Seabrock Station Sector 2 is based on the northern half of the 2-5 mile band from the seabrock Station. The eastern edge of this sector is the Atlantic shoreline. On the North, Sector 2 is bounded by the Hampton, Hampton Falls and Kensington town lines. The Kensington town line also comprises the west boundary of Sector 2. Along the southern edge, Sector 2 is bounded by the Seabrcok, Hampten Falls and Kensington town lines and by a short section of I-95.

Sector 2 includes the entire town of Kensingten. Most of Hampten and Hampton Falls are also included in this sector.

Sector 3 is based on the southern half of the 2-5 mile band frem the Seabrock Statien. The eastern edge of this sector is the Atlantic shoreline. Cn the north, Secter 3 is bcunded by the Seabrock and South Hampten tcwn lines, and by a short section of I-95. To the west, Sector 3 is bounded by the South Hampton and Amesbury town lines. The southern boundary of Sector 3 is defined by the Amesbury and Salisbury town lines.

i 5

Sector 3 includes t? entire towns of Amesbury and Salisbury. The portion of the tosn of Seabrook to the west of I-95 is also included in this sector.

Sectors 4 and 5: 5-10 Miles frem the Seabrock Station Sector 4 is the northern half of the 5-1 mile band from the Seabrook Station. The eastern boundary of Sector 4 is the Atlantic shoreline.

21

The inner boundary is defined alcng the North Hampton, Exeter and East Kingston town lines. The cuter border of Sector 4, identical to the EPZ boundary, is defined by the Rye, Greenland, Newfields, Brentwood and Kingston town lines.

Sector 4 includes the entire tcwns of Rye, North Hampton, Greenland, Stratha=, Newfields, Exeter, Brentwood, Kingsten and East Kingsten. A small portien of the City of Portsmouth is included.

The major pcpulation feature of Sector 4 is Exeter Center.

Sector 5 is the scuthern half of the 5-10 mile band frem the Seabreck Statien. The eastern bcundary of this secter is the Atlantic shoreline.

7.ie inner boundary of Sector 5 is defined alcng the Salisbury, Amesbury and South Hampton town lines. The cuter bcrder of Secter 5, identical to the EPO beundary, is defined by the Newbury, West Newbury, Merrimac, Newton and East Kingsten town lines. A small portien of the City of Haverhill is also included.

Sector 5 includes the entire towns of Newburypert, Newbury, West Newbury, Merrimac and Newten. A small pcrtien of the City of Haverhill is also included.

The majer pcpulation feature of Sector 5 is Newburyport center.

INC:.USICN CF THE CITY CF POR*SMCL""H There is some feel among elected officials of the City of Portsmouth, i

that the entire u_., .ui be included in the epa. :

l i

nclusion of the entire City of Portsmouth in the EP2 would result in a si.seable population located well beycnd the 10-mile radius of the plant.

This magnitude of modification in the EPZ boundary would require a clear indication of the City's desire to be included, expressed as a for=al petition from the City to the New Hampshire Civil Defense Agency.

22

l IV. PCPUI.ATION CF THE SEABRCCK STATICN EPZ TOTAL POPULATION CHARACTERISTICS The total per=anent resadent population of the Seabrook Station EP3, as defined for the purposes of this study, is 111,000 persons (Table 3). This population is distributed to 41,000 households.

The population of the EP: is spread fairly evenly throughout the EPZ with no single concentration of population accounting for more than 13 percent of total EP population. Population aleng the coast is somewhat more con-centrated than in the inland areas. The coastal towns and cities, with 37 percent of the total area of the EP:, have 50 percent of the total EPZ population.

The EP population is concentrated into the town centers and cities. For example, four such concentratiens (Exeter, Hampton, ,v:esbury and Newburyport) account for 50 percent of all pcpulation.

Seasonal and Oransient Poculation During the St==er =cnths, the population cf the IPZ is greatly increased by seasonal cesifents and transient persons visiting the area for short periods of time (overnight or day trips) .1/ Under peak conditions, on a St=mer Sunday, 78,000 seasonal and transient persens are added to the per=anent EPZ population of 111,000. This additional pcpulation is con-centrated in the beach t0wns, with Hampton accounting for about 40,000 persons and Salisbury next with about 19,000 persons.

2' /Two methods were used for esti=ation of the beach population: (1) built up from segments of per=anent, transient overnight and day visitors based on dwelling unit counts and weekend traffic counts into the beach area; and (2) based on actual count of vehicles made frc= low-level aerial photo-graphs taken on peak beach population days. Both of these =ethods produced cc= parable population estimates which also agreed closely with an inde-pender.t esti= ate made by EMM Associates.

23

... .. - - . ~ . ... . - .- . ..

. TABLE 3

TOTAL RESIOENT PCPULATICN OF THE SEABROCK STATICN EPZ i

GOVERNMENT UNIT PCPULATICN TOTAL TOTAL l

NEW HAMPSHIRE JURISDICTICN (1970) JURISDICTICN (1980)* SEABRCCK EPZ

.BRENTWCCD 1468 2170 2170 EAST KINGSTCN 838 1190 1190 EXETER 8892 10720 10720 a

GREENLAND 178,4 2210 2210 i

HAMPTCN 8011 10820 10820 HAMPTCN FALLS 1254 1500 1500 KENSINGTCN 1044 1350 1350

$ KINGSTON 2882 4640 4640 NEWFIELOS 843 1000 1000

NEWTCN 1920 4060 4060 NCRSI HAMPTCN 3259 4910 4910 PCRTSMCUTH 25717 23430 1000 RYE 4083 5230 5230 j SEABRCCK 3053 6000 6000 1 SCUTH HAMPTCN 558 800 800 STRAT9AM 1512 2500 2500 MASSACHUSETTS I- AMESBURY 11388 16560 16560 HAVEPRILL 46120 46340 200 MERRI: iAC 4245 4710 4710 NEWBURY 3804 4920 4920 NEWBURYPCRT 15807 16740 16740

' SALISBURY 4179 5150 5150 f

.i 1 WEST NEWBURY 2254 2690 2690 TOTAL 154915 184640 111070 ,

~'

DATA SCURCES FOR 1230 ESTIMATES: New Hampshire Office of Ccmprehensive Plan-

-ning. Interim Revisions, New Hampshire Population Projections for Towns and Cities to the Year 2000. August 1977: and Massachusetts Cepartment of Public Health Office of State Health Planning. Population Projections 1980-1985.

2 August 1978.

24 l l

l

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J AUTOMCBILE OMIEPSHIP Table 4 shows the distribution of autc= chile-owning and non-automobile owning households in the Seabrook Station EPZ. Scme patterns of automobile l ownership of interest in estimating evacuation times are noted:

o Thirteen percent of the households in the EPZ de not own 4

an automobile.

o A relatively large nu=ber of ncn-autcmobile owning house-holds are in Newburyport and Acesbury. These two areas,-

with less than one-third of the EPZ population, have almost i one-half of the non-autc=obile owning households in the EPZ.

i I

o Relat:. rely few non-automobile cwning households are in the

/

small newra and rural areas. For exa=ple, in Greenland, Kensington, !! orth Hampten and Seabrook, the fraction of a

non-autc=cbile cwning hcuseholds ranges frem 8 to 9 percent.

i The seasonal and ransient population is, for purgeses :f evacuation time 3

i estimating, assu=ed to be 100 percert aut:=obile owning.

PCPULATICN SECME ITS AS ::EFI!;ED FCR EVACUATIC:: A:!ALYSIS In estimating evacuation times, fcur population segments are identified on the basis of'how persons are evacuated f cm the EPZ (see Chapter VI):

3 (1) Auto cwning population. This population segment censists t

of all members of car owning families, except children in school'at the time of notification.

, (2) School population. All children at school at the time of notification, regardless of the automobile ownership status ,

of their families.

4 25 4 ,

-1

e,. ,.

TABLE 4 AUTO CWNERSHIP IN THE SEABROCK STATION EPC

- HCUSEHOLbS BY AUTCMOBILE ANALYSIS ZCNE/ SEABROCK EPZ AVAILABILITY GOVERNMENT UNIT 'PCPULATICN HOUSEHOLDS O 1 2 3+ ,

NEW HAMPSHIRE 1 BRENTWCCD 2170 804 67 443 247 47 2 EAST KINGSTCN 1190 441 37 243 135 26 3 EXETER 10720 3970 619 2263 1004 84 4 CREENLAND 2210 819 68 452 251 48 4 5 HAMPTCN' 10820 4007 240 1851 1639 277 6 HAMPTCN FALIS 1500 556 46 307 171 32 i.

7 KINSINGTCN 1350 500 42 276 154 28

+ 8 KINGSTCN 4640 1719 143 949 528 99 i

! 9 NEWFIZI;;S 1000 370 31 204 114 21 l

10 NEWTCH 4C60 1504 125 830 462 87

' 11 NORTH HAMJTON 4910 1919 151 1004 558 100 12 PORTSMCC"lH 1000 370 31 204 114 21 13 RYE 5230 1937 45 1046 713 133 14 SEABRCCK 6000 2222 209 1409 440 154 15 SCUTH HAMPTCN 800 296 25 163 91 17 4

13 STRATH-3! 2500 926 77 511 284 54 J

MASSACHUSESS 17 AMESBURY 16560 6133 1147 3434 1282 270 l 18 HAVERHILL 200 74 13 41 17 3 j 19 MERRIMAC 4710 1744 309 959. 398 78 20 NEWBURY 4920 1822 322 1002- 415 83 21 NEWBURYPORT 16740 6200 1321 3292 1345 242 22 SALISBURY 5150 1907 248 1064 494 101 23 WEST NEWBURY 2690 996 176 548 227 45 TOTAL 111070 41136 5492 22495 11083 2066 1

i a

9 26 T

- _ . _ , , , - , -- . . . , , . . , __m _

. l 4

I

() Non automobile ownine households. All persons (except school l children)'in households where a car'is not reasonably available for evacuation.

(4) Population in institutions such as hospitals and nursing homes, etc. and not having access to a private vehicle for evacuation.

s

} Rearranging the EPZ population into these categories (Table 5) reveals 1 that:

c Most of the pcpulation (71 percent) is in the automobile-i owning segment, o The next largest pcpulation segment is school population, l

accounting for about 19 percent of the EPZ population.

i o Non-automobile owning population accounts for 7 percent of Seabrock Stacion EPZ inhabitancs. As noted above, this pcpulation is concentrated in the Amesbury and Newbur;gert i

areas.

1, i

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TABLE 5 i

SEABROCK STATION EPZ POPULATICN BY SEGMENTS Percent of Population Segment Population 17 Total Poculation Automobile-owning2 / 71 Population - 78,790 School Population 3/ 21,600 19 Non-Auto = obi's Owning Popultcion 7,130 7 Population in Institutions 3,500 3-TOTAL 111,070 100 4

d 1

L i

1

-l

-1/Permanent population. Seasonal and transient population of 78,000 persons not included. Seasonal'and transien: popula-tion is entirely in " Automobile-owning Population" segment.

-2/Automobile-owning population excludes school population.

-3/All school students regardless of car-owning status of their household.

l 28

-. -- l

t i.

i 1 V. THE EVACUATICN SEQUENCE FCR SEABRCCK STATICN 4

i GENERAL CONCEPT CF EVACUATICN i

S.e overall. purpose of the evacuation is simply to remove the popula-tion of the EPZ as rapidly as possible. The evacuated pcpulation is directed to reetytiva centers, where it i- temporarily lodged. Some of the evacuaced population will go to the homes of nearby relatives and acquaintances.

Wherever possible, the evacuating pcpulation will leave the EP: : by :neans of private autcmobiles. Persons wi-lout autcmobile transportation will be transported by transit vehicles, ambulances and other available vehicles.

In general, meterists will leave the EPZ by the most direct route, that is, the shortest rcute out of the EP::. Traffic direction at seme key locations sill help balance- the traffic volumes en the evacuation routes.

Nor=al traffic flow will be observed, with streets open to all vehicles and functioning in their usual manner.

In estimating evacuatien times, the EPZ population is grouped according

! to how it evacuates: (1) auto owning population, (2) school population I (3) non-auto cwning population and (4) persons in institutions. .

Each of these grcups folicws a different sequence in evacuating:

l 1

i o the auco cwning population, after receiving the notice to evacuate, assembles the family (except for children at school) at home, prepares for evacuating the home and drives out of the EPZ. Non-residents (for example, beach visitors) simply

- assemble the group with which they are traveling, and leave' the area.

t 29 p

9

, .. 4 o the school populatien is transported out of the EPZ directly from the schools. School buses are used to evacuate this population.

o non-auto owning households prepare for leaving their heme, assemble at collection locations, and are then transported out of the EPZ in buses or other vehicles, o persons in institutions (hospitals, etc. ) are prepared for evacuation, then transported out of the EPZ in buses and ambulances.

FCSSISLE IVACUATICN TIME PERICDS The length of time needed for evacuation of the Seabrook Station EPZ wili vary, depending en the time of day, day of week and season of year in which the evacuation occurs. Four possible ime periods are identified:

o Nighttime o Oaytime en a summer weekend ("Su=mer Sunday" case) o Daytime en a winter weekend o Daytime on a " winter weekday" case In estimating evacuation times, the " worst cases" of these four time periods should be adopted; that is, evacuation time estimates should reflect conditions likely to cause the lengest evacuation times.

Nichttime Evacuation In a night evacuation, the notification process would be slowed by people having to wake up and comprehend the evacuation information

- being broadcast. Additional time would be required to prepare vehicles

- for evacuation in the dark. Cn the other hand, for most segments of 30

I the population, the families would be intact at the time of notification, since schools are not in session and relatively few employees are on the job.

Daytime on a Summer Weekend (" Summer Sunday" Case) 1 In any daytime evacuation, the notification time is at a minimum, since

=ost people are awake and many are already listening to radio and tele-vision broadcasts. Familes are more likely to be at the same location on weekends, since schools are not in session and relatively few persons are at work. Cutdoor recreation is at a peak during this season, and many non-residents are at the beach areas.

Daytime / Weekday Evacuation (" Winter Weekday" Case)

Ouring a daytime / weekday evacuation, a majority of the employed population would be en the job. During most of the year, schools are in sessien and the transportacion of students beccmes a large issue in any evacuation.

For much of-the populatien, a daytime / weekday evacuatien creates additional action steps, since families must be assembled prior to leaving the hcme and evacuating the EPZ. Also, during the daytime / weekday period, the like-lihood of persons being away from home without a vehicle are greatest.

Critical Time Periods For the evacuation of the Seabreck Station EPZ, the critical time peried--

that is, the period for which evacuation is likely to require the mest time--is the "Su=mer Sunday". During this period, the population and vehicle accumulation in the EPZ is at a maximum.

The next most critical time period is the "Wint'r e Weekday" period.

During this period, the time needed to assemble family units is likely 1 to be at its maximum. Furthermore, the daytime / weekday periods raises issues of school pcpulation evacuation which do not exist in other time periods.

31

Separate evacuation time estimates are prepared for both of these time periods,._i.e., for."Su=mer Sunday" and " Winter Weekday".

PCPULATICN SEGMENTS TO 3E EVACUATEC As a first step in estimating the evacuation times for the Seabrook EPZ, 1 its population is divided into segments. A separate time estimate is made for each of these segments. This method, by recognizing the various ways in which population leaves the EPZ, allows a more precise prediction of required times. The basis for the various population segments is HCW that segment of population leaves the EPZ. Consequently, four population segments are identified:

(_1) Auto owning populatien, who evacuate by driving cuu in private autcmebiles. This population segment censists of all members of car-owning hcuseholds, except children at school.

(2) School population: that is, all children at schcol. This

]

pcpulation is evacuated directly frcs schcols, in school buses.

(3) Ncn auto-cwninc households: all persens in households where a car is not reasonably available for evacuation. Scme of this pcpulation is evacuated by friends and relatives. Those not evacuated by friends or relatives assemble at collectien points, and are evacuated by bus.

(4) Population in institutiens such as hospitals, nursing homes, j ails , etc. This pcpulation is evacuated directly from the institution, by bus or special vehicle.

Family Units Families (excluding children in school) are evacuated as units. Cn weekdays, assembly of the family units involves members returning hcme 32

from their jobs, shcpping, etc. Cn weekends, many families are already assembled and can immediately prepare -to leave home. Ncn resident families (for example, beach visitors) are already assembled, and evacu-ate with almost no further preparation.

EVACUATICN ACTICN STEPS For each population segment,.the evacuation sequence consists of a series of action steps. These are clearly defined actions, performed in a predictable sequence (see Figure 7) .

Subdividing the' evacuation process into these discrete steps improves the accuracy of the estimates of time needed for the entire evacuation.

In place of a single estimate of the entire evacuation process, for which data is not available, this precess permits the estination of times for each individual step, for most of which data is readily available.

Public Acency and Private Steps Some of the evacuation steps identified in Figure 7 are performed by public agencies. Fcr all population groups, the "Evacuatien Notice" action is the responsibility of public agencies. For these persens evacuated by means other than privately owned vehicles, public agencies have the additional responsibility for the actual evacuation step; for example, " Evacuate School Population in Buses", " Evacuate Ncn-Auto Cwning Households in Buses", etc. For pcpulation in institutions, the "Mobilise Population" step is also a public agency responsibility.

Those acticn steps not the responsibility of public agencies are done at the initiative of the individuals being evacuated. For the auto owning population, all steps after the initial " Receive .3readcast Information" are private actions; that is, they are initiated by the individuals being evacuated. Similarly, two of the steps in the evacuation of non-auto

- owning nouseholds are private steps.

33 T

e

5 AUTO OWNING SCHOOL NON AUTO OWNING POPULATION IN HOUSEHOLDS POPULATION HOUSEHOLDS INSTITUTIONS l

RECEIVE RECE!VE RECEIVE RECEIVE SRCACCAST BROA0 CAST BRCA0 CAST 3RCAOCAST INFCRMATICN INFORMATICN INFORMATION INFORMATICN Y V V V EVACUATE PREPARE SCNCOL FOR wCSILI:E LEAVE PLACE EVACUATING PCPULATICN OF sCRK POPULATICN IN SUSES M0wE ,

, Y Y Y EVACUATE ASSEMBLE AT INSTITUTICNAL

CRK TO MOME PCPULATION TRAVEL CCLLECTICN POINTS 1:4 SLSES OR SPECIAL VEw!CLES Y Y EVACUATE PREPARE FCR NON-AUTO EVACUATING CWNING nCME HCUSEHOLCS IN BUSES Y

CRIVE CUT

' CF EPZ

~

Figure 7. Population Segments and Evacuation Sequences 34

EVACUATICN CF AUTO CWNING POPULATICN The action steps described in the f ollowing sections describe the sequence of evacuation for resident auto owning households, evacuating the area during the daytime / weekday period. For some other components of the auto owning population, the sequence is shortened and certain action steps are anitted. For example, non-resident beach pcpulation does not need to return home frcm work, nor to prepare for leaving a household. In the calculation of evacuation times, only those action steps appropriate to the population ecmponent are included.

F.eceive Broadcast Information Following the decision to evacuate, the first activity is the notification of the public that an emergency exists. This is acccmplished by the sounding of sirens, and activation of other alert systems (such as NCAA).

This notification alerts the public that an emergency exists, and that they should tune in to radio and television broadcasts for further informatien.

The next activity is the broadcast of radio and televisien infommation, with specific instructions for evacuating.

Varicus other backup measures are used to inform the pcpulation which might not be reached by the above means. Mobile public address units will circulate through built up areas of the EPZ. Public address systems will be used at large concentrations of population, such as the beaches and race track. Scme households, particularly in the more remote rural areas, will be notified directly by telephone call.

Leave Place of Work )

The rate at which area workers will leave their jobs to return hcme to ;

prepare for evacuation depends o., the particular work environment and ;

upon the responsibility level of the werker. It is to be expected that 35-

. :, j l

1 I l most of the work force will be able to leave their jobs almost immediately, quite similar to a normal departure from work at the end of the workday.

A number of workers, however, will require' seme job "close-down" time in

- work situations for example, those that involve machinery, construction equipment, -or cash registers in retail sales establishments. Supervisory 4 employees, managers and independent business operators will generally require the greatest amount of time to secure their place of work and to l assure that all employees and others on the premises have departed.

1 Work-to-Home Travel Travel of the employees frem their place of work to home is essentially a normal journey-to-work travel time distribution. The maximum trip length for work trips in the EPZ is not likely to excee,i 20 miles, and

, the average trip is less than three miles. An average travel speed of 20-30 miles per hour is typical for the travel hcme for area workers.

J

! This movement of workers, because of the short time over which it occurs, can be expected to cause seme traffic congestion. This level of congestion should be similar to that occurring during the twice-daily work travel peak. It is expected that the road system will handle this volume of traffic with essentially the same level of service as during the peak hours on.a typical working day.

j Prepare for Evacuating Home i

~

People can be expected to react differently to any emergency situation,

~

and the conditions imposing an evacuation need on the area population are likely to generate great differences in the amount of time that people will spend'in preparing to leave their home. Three factors in particular affect the amount of time needed to prepare for evacuating a household:

(1) Whether c- nse adults are at home when nvtice to evacuate-is 4

received. If so, preparation time is shortened (ccmpared to 36

. ,.=

households where no adults are at heme) since preparation for evacuation can begin before werkers arrive at home.

(2) -Number of children and other dependents at home. These increase the time needed to prepare the household for evacuation.

(3) The amount of property to be secured. Farms are the extreme case, and may require up to two hours to secure. On the other hand, small households, for example, in apartments, can be prepared for evacuation in minutes.

Travel Cut of the EPb After households are secure, auto owning households will drive cut of the EPZ by the most direct routes available.

The auto owning population will drive either to reception centers established cutside the EPZ, or to other destinations (primarily hemes of friends and relatives) of their own choosing.

Public agencies will give routing advice for this travel. by means_of preparedness plans prior *; .e emergency anc nrcuyn-indcrmation broad-casts during the actual avacuation. Police officers will also channel ficws of traffic out c i the EPZ.

Evacuating traffic will use all available reads out of the EPZ. Traffic volumes are too large to permit evacuation to .be confined to some selec-ted reads.

During the evacuation, normal traffic cperations will generally preval .

J Specifically, two-way streets will continue in two-way operation, traffic signals will continue to function, and so forth. Some mcdifications might be mader for example, some three-la e roads may be cperated in an . ,

"imbalanced" manner, with two lanes flowing out of the EPZ and only one l 4 lane used.for inbound traffic. 4 37

- .'. j 1

1 During such of the evacuation, traffic will flow freely, although at reduced speeds. However, at certain locations and during certain periods, traffic congestion is expected.

EVACUATION OF SCHOOL PCPULATION Receive Broadcast Information Following the decision to evacuate, the local preparedness agencies notify schools directly of the need for evacuation. This is dene through radio warning systems and telephone calls directly to the schools.

Siren syste=s will serve as a backup method of notifying schools. Coverage of the school population by this method is high, since almost all schools are in populated areas within siren range.

Evacuate Schcol Population in Buses The school populatien is transported directly by bus frem school to reception centers. Generally, an entire school will be transported to the same reception cr. iter. Schcol children will not return heme prior to evacuatien. The picking up of school children at school by families is discouraged.

School bus fleets frem all districts within the Seabrook EPZ and from neighboring disuricts within about a 20 mile' distance of the EPZ will be used for evacuation. All school buses used in these districts, whether publicly or privately owned, will be used to evacuate students from the EPZ.

NCN-AUTO CWNING HOUSEHOLOS Receive Broadcast Information The procedure for receiving broadcast information is the same as for auto owning population (above). This includes the sounding of sirens, broadcast 38

,' 'e' i' information, mobile public address acui possibly some direct notification by telephone calls.

Prepare for Evacuating Home This step is the same as for auto owning pcpulation (above) . As in the case of auto owning pcpulation, primary factors in the time required for. this action are whether or not an adult is at hcme at the time of notification, the number of dependents to be evacuated and the extent of property to be secured..

4 J

Assemble at Collection Points A significant fraction of the non-auto owning pcpulation (perhaps as much as 50 percent) will be evacuated as passengers in private vehicles driven by family, neighbors or friends. This component of the ncn auto-3 owning population could then be considered, in effect, as part of the auto-owning population.

Persons from non auto-owning households who do not evacuate as passen-gers in private vehicles wil' tssemble at locations (for example, churches and public buildings) designated as collection points.

From the collec-tien points, buses will transport them to the reception centers.

Most of the pcpulation in settled areas lives within one mile of a collec-tion point, and the majority of this population will walk there. Persens unable to walk to the collection point will, by telephone, request transit service from their home to the collection point. Rural ncn-auto owning population will be taken to collection points in transit vehicles and in some cases, autorobiles.

Evacuate Non-Auto Cwning Households in Buses Transit buses will pick up evacuees who have assembled at the collection points, and take them *.o the reception centers outside the EPZ.

i 39

1'.-

, )

i l

l Potential sources of buses include private common carrier fleets, public transit systems from within the EPZ, and public transit systems frca outside the EPZ, particularly from the Boston urban area.

POPUIATION IN INSTITUTICNS Paceive Broadcast Inferr. tion Following the decision to <.vacuate, the local preparedness agenc_ s will notify institutiens directly about the need to evacuate. This is done by radio warning system and telephcne calls.

The siren notifi cation system is a secondary backup method of notifying institutions. Siren coverage of institutions is high, since almost all of them are located in populated areas and therefore within range of a siren.

Mobilize ?cpulation The institutional pcpulation is instructed abcut evacuation precedures by the staff of that particular institution. Necessary personal effects are assembled. Essential medical records are gathered.

f Evacuate Institutional Population in Buses or special vehicles Transit _ buses will pick up ambulatory hospital patients, nursing home rerf. dents and other persons net requiring ambulance transportation.

These passengers will be transported directly to the reception centers.

Generally, all residents of a given institution will be evacuated to the same reception center. Potential sources of buses include private ccmmen carrier fleets, public transit systems within the EPZ and public transit systems frcm cutside the EPZ, particularly frem the Boston urban area.

)

i 40 l

4

- Non-ambulatory persons will be transported directly from institutions by ambulance. These vehicles will be drawn frcm the fleets normally based within the EPZ, supplemented by ambulances frem neighboring

- communities.

4

, Ambulances used in the evacuation of institutions will make three round l'

trips.

SUMMARY

OF THE EVACUATION PRCCESS

, In order to examine the " worst case" for which evacuation times are at a maximum,. the evacuation is. assumed to cccur during the daytime on a summer weekend. The next most critical period, daytime on a weekday, I is also examined.

Four_ population groups, having distinctly different evacuation methods, i

are recognized:

I (1) auto cwning population, which evacuates in private autemcbiles a

(2) school population, which evacuates in school buses i- -(3) non-auto cwning households, which assemble at collection points and evacuate in buses (4) persons in institutions, who are evacuated directly frem the ,

institutions in buses and ambulances.

a For each population group, the evacuation sequence consists of a number of clearly defined action steps as summarized-ia Table f.

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TABLE 6 i

SUMMARY

OF EVACUATION ACTICN STEPS POPULATION SEGMENT ACTICN STEPS AND DESCRIPTICN AUTO CWNING PCPULATICN 1. RECEIVE BROADCAST INFORMATICN,

, (All members of households, including instructions for evacua-except school children, ting.

having a private vehicle

2.

LEAVE PLACE CF WORK availacle for evacuation)

3.

WORK-TO-HCME TRAVEL, similar to normal work trip

4.

PREPARE FOR EVACUATING HCME (cloce house, secure property)

5. DRIVE CUT OF THE EPZ in private vehicles, using most direct routes SCHOOL PCPULATICN 1. RECEIVE BROADCAST INF0FMATICN, (All persons in schools, including instructions for evacua-whether e Salic or private) ting

2. EVACUATE SCHCOL PCPULATICN IN BUSES from districts in IPZ and other sources NCN-AUTO CWNING PCPULATICN 1. PICEIVE BROACCAST NFCRMATICN, (Persons not havi:q a including instructions for evacua-private vehicle available ting for evacuaden) 2. PPIPARE FOR EVACUATING HCME (close house, secure property)

3. ASSEMBLE AT CCLLECTION POINTS such as churches or public buildings

4. EVACUATE NCN-AUTO CWNING PCPULATICH IN BUSES frcm EPZ and other sources PERSCNS IN INSTITUTICNS 1. RECEIVE BROADCAST INFORMATICN, (Hospitals, nursing homes, including instructions for evacua-Naval Base, etc.) ting

2. MCBILIZE POPULATION, prepare popula-tion for evacuation

3. EVACUATE INSTITUTICNAL POPULATICN IN BUSES OR SPECIAL VEHICLES

These steps emitted by non-residents; for example, beach visitors.

l l

42 J

,a VI. EVACUATION RCUTES GENERAL STRATEGY CF EVACUATION RCUTING This chapter considers the evacuation of the largest population segment of the EPZ: those-using private autcmobiles. The basic cbjective of evacuation routing for autceabile traffic is to permit vehicles to exit

, as rapidly as possible from the EPZ. The overall evacuation strategy is derived frcm key geographit features of the EPZ such as the location of the Seabrook Nuclear Power Station and the constraint on eastward movement presented by the Atlantic Oceau, as well as from the characteris-tics and configuration of the road network. The basis of the strategy is the evacuation of principal year-round population centers by the most direct movement possible. The major ccmpenents of this strategy are illustrated in Figure 8 and summarized belcw:

o Newburyport, the largest population concentration of the EP2, should be evacuated directly to the south.

o Amesbury, the second ranking population center, should be evacuated directly to the southwest.

o Hampten, the largest population center within a 5-mile radius i

of the power station, should be evacuated directly to the north, i

o Exeter and its surrounding area should be evacuated directly )

to the west and northwest.

)

i These four major movements define the corridors for evacuatien of 50 percent of the winter weekday :.+ u ion of the EPZ. Clearly, this strategy provides for the separation of the major flows which is impor-tant to the minimization of traffic conflict.

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US 1 AND 1A Figure 8. E acuation Routing Strategy 44

ROAD NETWORK FOR VEHICLE EVACUATICN The~ characteristics of the road system within the EPZ were presented

- in Chapter II. A~ capsule description of the facilities available for evacuation traffic would note that the EPZ is served by a-full ange of facility types that includes two interstate highways, Federal primary

! system routes as well as pr.,;ary and secondary state roads. Examination of the road network indicates that north-south movement is more direct 4

than east-west travel patterns. The major facilities, I-95 and P.oute 1 4 are continuous and offer high capacity for traffic exiting the area to a

the north or south. Conversely, there is no facility of this capacity for east-west traffic and those roads that do serve this movement are relatively indirect.

! Figure 9 identifies the " gateway" points where roads cross the boundary of the EPZ. This set of eighteen gateway points represents de total V

roadway capacity for evacuation. In general, the capacity of a roadway is determined by the capacities of its intersections, rather than by its cross section at the non-intersection locations. In the case of evacua-tion routes, capacity is likely to be determined by a " critical inter-section". These are intersections that represent the " bottlenecks" en the evacuation routes. In general, they are locations at which (1) the evacuation route has a high traffic volume, after having collected traffic from various tributary roads, and (2) cross-street traffic at.

the intersection is significant, reducing the amount of time available for evacuation traffic to move through the intersection.

4 The capacity of an intersection is based on a maximum flow of 1500

~

vehicles per lane hourly, with full assignment of the right-of-way j (or, in other words, 1500 vehicles hourly if there is no cross street l

{ traffic). This capacity is then adjusted downward to reflect the demands of the cross traffic. At the critical intersections, which are establishing the capacity on the evacuation routes, the total 1

45

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Figure 9. Evacuation Gateways and Capacities .

46

capacity is adjusted downward to 80 percent of the maximum to reflect this cross street traffic. The resulting capacity is 1200 vehicles per lane per hour.

5 The total capacity of the Seabrook EPZ gateway points is approximately 38,400 vehicles per hour. This estimate of total capacity is based upon the use of hard surface highways and primary and secondary roads as evacuation routes and does not include local urban streets and unpaved roads. .The gateway capacity of three-lane facilities such as Routes 1 and 1A has been calculated on the basis of assumed two-lane operation

~

cutbound.

FORECASTING EVACUATICN TBAFFIC The raview of data on the characteristics of the population of the EPO included an assessment of auto ownership patterns in the area. At this point in the analysis, we consider the generation of autemebile vehicle trips for the evacuation cf those househcids with an auto available.

It is important to recognize that autemcbile evacuation trips and total automcbiles within the EPZ are not necessarily the same.

I5e trip generation step is a calculation based upon the auto cwnership patterns of the year-round residents and the vehicles associated with beach visitors and seasonal residents. The patterns of auto cwnership and the-median household size (nunber of persons per hcuseholdi indicate

!- that there are households with fewer vehicles than licensed drivers and households with more vehicles than licensed drivers. Recreational vehicles, for example, are often " excess" vehicles that are used only for special purposes. The trip _ generation step is built up from the segments of the auto-owning population and recognizes that households witn only one or two vehicles will utilize a greater proportion of their households with three or more vehicles. Table 7 presents the total vehicle trips forecast _ for each zone under the two different evacuation scenarios.

r 47

- , .l TABLE 7

~

EVACUATICN TRAFFIC FORECAST (VEHICLE TRIPS)

ANALYSIS ZONE / CASE A: SUMMER SUNCAY CASE 3: WINTER WEEKDAY GOVERNMENT UNIT TCTAL PEAK HCUR TOTAL PEAK HOUR NEW HAMPSHIBE 1 BRENTWOOD 908 782 908 782 2 EAST KOIGSTON 498 429 498 429 3 EXETER 3937 3390 3937 3390 4 GREENLAND 925 796 925 796 5 HAMPTCN 18828 18152 4864 4188 6 HAMPTCN FALLS 628 541 628 541 7 KENSINGTCN 563 485 563 485 8 KEIGSTCN 1939 1669 1939 1669 9 NEWFIELOS 417 359 417 359 10 NEWTCN 1697 1461 1697 1461 11 NOR"?.I HAMPTCN 2053 1768 2053 1768 12 PORTSMOUTH 417 359 417 359 13 RYE 2382 2051 2382 2051 14 SEABROCK 5419 5086 2397 2064 15 SOUTH H7APTCN 334 288 334 288 16 STRAT'fAM 1045 900 1045 900 j MASSACHUSETTS 17 AMESBURY 3897 5077 3397 5077 18 HAVERHILL 73 63 73 63 19 MERRIMAC 1712 1474 1712 1474 20 NEWBURY 1791 1542' 1791 1542 21 NEWBURYPCRT 5794 4989 5794 4989 22 SALISBURY .7291 7012 2007 1728 23 WEST NEWBURY- 979 843 979' 843 TOTAL 65227 59516 43257 37246 De

~),- ~..

This forecast level of auto vehicle trips averages approximately 85 percent of the estimated total nunber of vehicles in the EP3. This level of vehicle utilization appears reasonable when allowances are made for vehicles being outside the EPZ at the time of evacuation, vehicles being out of service for mechanical problems, and the number of " excess vehicles" in households where there are not as many licensed drivers as vehicles.

Table 7 also presents information on the distibution of the vehicle I

demand. Estimates for the peak hour of travel are shown for each evacuation scenario on a zone by zone basis. Cemand peaking information

'is of interest because it places the tctal travel demand into the same temporal framework as capacity. The distribution of all evacuation activities over time is a central feature of the approach taken in this analysis, reflecting conditions as they are actually likely to cccur.

Inspection of the activity distribution- curves developed in this study

for the evacuation of the Seabrook ErZ indicated that 86 percent of the population would be attempting to exit within the peak hour of demand.

These peak hour de=and volumes can be related to the hourly capacities of the road network to estimate supply / demand imbalances and censequent traffic congestion and delay.

. INDIVICCAL EVACUATION RCUTES In order to assess the time required to evacuate the Seabrook EPZ, individual exit routes were developed for each of the analysis enes or towns within the area. This enables a relatively " fine-grained" analysis that can be related to actual concentrations of population and the evacuation route options available to each subarea.

l l

A series of individual evacuation routes are then determined for each

one following these. guidelines: i i

o The route must lead fairly directly out of the EPZ, at I should not have a circuity of greater than 150 percent. (Circuity is j 49 l

the amount by which the actual road distance exceeds the straight-line distance).

o The routes must be at least collector streets in the urban areas, or at least paved secondary roads in the rural areas.

Local urban streets and unpaved rural roads are not designated as evacuation routes.

The resulting system of evacuation routes for each case is shown in Figures 10 and 11. Some of the roads are designated as the evacuation routes for more than one analysis zone. Also, some analysis zones have

=ultiple evacuation routes designated.

Far each of the evacuation scenaries carried through the analysis, the 1

forecast traffic volumes were assigned to the system of evacuation routes.

In the absence of a detailed local plan for the management of evacuation traffic, a number of assumptions must be made in order to reflect the conditions reasonably attainable with available local management rescurces.

Therefore, for the purposes of this analysis, it was assumed that overall, craffic facilities would be operated in a relatively normal fashion. That 4 is to say that few instances of special traffic management capability were assumed. Noteworthy exceptions include assumed two-lane entry to I-95 nc.phbound at Route 51 and assumed use of the center left-turn lane as an outbcund. travel lane on Route 1 and 1A. In addition to these cperating characteristics, a relatively low-level of traffic control

~

intervention and direction was assured for a limited number of intersections.

Beyond this, little effort was made to balance or optimize traffic flows.

It is important to recognize that individual motorists will have very imperfect knowled e of traffic conditions elsewhere in the region and will only have a limited set of route options for evacuation. Thus, significant imbalances and congestien are inevitable because severe peaking characteristics foreclose chances of a situation where available-50-

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Figure 11. Evacuation RoutesiCase B, Winter Weekday I

l 52 l

roadway capacity would be utill:ed most efficiently. Still, it is worth noting that even under an ideal assumption of optimal traffic balance with full utilizatien of gateway capacity, there would be 1.7 hcurs of traffic flow through the gateways in the su=mer-Sunday case and 1.1 hours1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months in the winter-weekday case. Of course, actual evacuation times will be much longer reflecting the effects of " bottlenecks" and traffic congestion.

Figures 10 and 11 present the forecast peak hcur traffic volumes by route for each of the evacuation scenarios. These volumes represent a believable balance of demand, based upon the congestion and route alter-natives presented to motorists evacuating each sone.

?EFSCTP.ANCE CF THE EVACUATICN TRAFFIC SYSTEM The traffic volumes forecast for the evacuation routes indicate that there will be a broad range of traffic system operating conditions under both of the evacuation scenarics. The leading characteristics of the evacuation traffic system are described generally belcw. A more detailed analysis of the traffic cengestien and delay is provided in a subsequent chapter. An overall assessment of evaciatien traffic conditions indicates that:

o The largest problems in the winter-weekday case are related to north-south movement. A few areas and roadways emerge as ,

critical areas for estimation of evacuation times and traffic delays.

o The largest problem in the su=mer-Sunday case is in westbound movement away from the beaches. The limited nature of the transportation network in beach areas means that the few available evacuation routes will be swamped with traffic. As vehicles clear the beach areas, problems will continue at north / south gateway points.

53

,. * .o o Movement to the southwest, west and northwest are relatively unconstrained. Analysis indicates that backups will occur but that these should be relatively limited in scope and duration because the capacity exists to accommodate anticipated peak hour ficws, o The major traffic facility in the EPZ, I-95 will experience relatively poor utilication. As the largest facility in the area it would be expected that I-95 would be utilized to the utacst. Analysis indicates, however, that there are serious problems associated with the use of I-95 for evacuation.

o The proximity of the Seabrook Nuclear Power Station to I-95 is one factor ILniting the use of this evacuation route. A fundamental tenet of evacuation planning is that few motorists will drive toward the source of the radiation and thus increase their exposure to health hacards. As a result, use of the access ramps to I-95 at Seanecok is largely precluded.

t o Lack of access points prevents greater use of I-95 for ncrth-bound evacuees. The Hampton interchange at Route 51 is the only access to I-95 north of Seabrook within the IPZ. Thus the use of this major, multi-lane facility is constrained by the capacity of the on-ramps at a single interchange.

o As access routes to I-95 (both north and south of Seabrcok) beccme concested, traffic is forced cnto Route 1. As a result this facility will experience a larger volume of demand relative to its capacity than the interstate facility.

l l

1 54

.. i i

l i :VII. _

SUMMARY

'CF EVACUATION TIME ESTIMATES 1 METHOD FCR ESTIMATING EVACUATION TLMES E Population Secments l

Evacuation times are estimated separately for each of the four popula-tion groups discussed earlier:

s (1) Auto. Owning Pcpulation i

(2) School Population (3) Non Auto Cwning Pcpulation (4) Populatio in Institutions Time Periods J

Evacuation times are estimated for. two different time periods (cases) as l

discussed previcusly in Chapter V:

i (1) Daytime on 1 -Su=mer Sunday", and (2) Daytime on a " Winter Taekday" 1

Action Steps Each population segment follows a specific sequence of action steps in evacuating the EPZ. (See Chapter V for a detailed ' discussion of these steps). The times needed to complete each of these steps-is then estimated. For the auto owning households, for example, estimates are 1 l

1 55

. - . . ~ - - .

AUTCMOBILE CWNERSHIP J

- Table 4 shows the distribution of autcmobile-owning and non-autcmobile owning households _in the Seabrook Station EPZ. Scme patterns of automobile ownership of interest in estimating evacuation times are noted:

o Thirteen percent of the households in tae EPZ do not own an automobile.

o A relatively large number of non-autcmobile owning house-holds are in Newburyport and Amesbury. These two areas, with less than one-third of the EPZ population, have almost one-half of the non-automobile owning households in the EPZ.

-o Relatively few non-autc=obile owning households are in the small towns and rural areas. For example, in Greenland, Kensington, North ~Hampton and Seabrook, the fraction of non-autcmcbile cwning households ranges from 8 to 9 percent.

The seasonal aid transient pcpulation is, for purposes f evacuatien ti=e estimating, assumed to be 100 percent automobile owning.

PCPULATICN SEGMENTS AS DEFINED FCR EVACUATICN ANALYSIS In estimating evacuation times, four population segments are identified on the basis of how persons are evacuated from the EPZ (see Chapter VI) :

(1) Auto owning population. This population segment consists of all members of car owning families, except children in school at the time of notification.

.(2) School copulation. All children at school at the time of notification, regardless of the automobile ownership l status ,

of their families.

25 I

TABLE 4 AUTO CWNERSHIP IN THE SEABROCK STATICN EPZ HCUSEHC CS BY AUTCMOBILE ANALYSIS ZCNE/ SEABRCCK EPZ AVAILABILITY GCVERNMENT UNIT PCPULATICN HCUSEHOLDS 0 1 2 3+

NEW HAMPSHIRE 1 BRENTWOOD 2170 804 67 443 247 47 2 EAST KINGSTON 1190 441 37 243 135 26 3 EXETER -10720 3970 619 2263 1004 84 4 2210 819 68 452 251 48 GREENLAND 5 HAMPTON 10820 4007- 240 1851 1639 277 6 HAMPTON F;J.LS 1500 556 46 307 171 32 7 KENSINGTCN 1350 500 42 276 154 28 8 KINGSTCN 4640 1719 143 949 528 99 9 NEWFIE OS 1000 370 31 204 114 21 10 NEWTCN 4060 1504 125 830 462 97 11 NORTH EvJTON ' 4910 1819 151 1004 558 106 12 PORTSMCUTH 1000 370 31 204 114 21 13 RYE 5230 1937 45 1046 713 133 14 SEABRCCK 6000 2222 209 1409 440 164 15 SOUTH HAMPTCN 800 296 25~ 163 91 17 16 STRA'" HAM 2500 926 77 511 254 54 MASSACHUSET"'S 17 AMESBUP.Y 16560 6133 ll4'i 3434 1282 270 18' HAVERHILL 200 74 13 41 17 3 19 MERRIMAC 4710 1744 309 959 398 78 l

I 20 NEWBURY 4920 1822 322 1002 415 33 j 21 NEWBURYPorc 16740 6200 1321 3292 1345 242 i

22 SALISBURY 5150 1907 248 1C64 494 101 23 WEST NEWBURY 2690 996 175 548 227 45 l TOTAL 111070 41136 5492 22495 11083 2066

~26

a

?.

(3) Non-altorobile owning households. All persons (except school children) in households where a car is not reasonably available for e.racuation.

4 (4) Pooulation in institutions such as hospitals and nursing homes, i etc. and not having access to a private vehicle for evacuation.

I Rearranging the EPO population into these categories (Table 5) reveals that: r i

t j

o Most.cf the population (71 percent) is in the automobile-1 owning segment.

'! i o The next largest population segment is school population, j

accounting for about 19 percent of the EPO population.

1 o Non-autencbile owning population accounts for 7 percent of Seabrcok Stacion EPZ inhabitants. As noted above, this pcpulation is concentraced in the Amesbury and Newburyport areas.

1 l-J f

27

a i

TA3LE 5 ,

SEABROCK STATICN EPZ POPULATICN BY SEQ 1ENTS t a

i Percent of 37 Population Segment Populatiop Total Population Automobile-Cwning2 / 71 Population - 78,790 ,

School Population 3/ 21,600 19 4 Non-Automobile Cwning Population 7,130 7 i

(

Population in 3,500 3 j Institutions i

f TOTAL 111,070 100 r

i 1

i i

i t

1 i

-1/Permanent population. . Seasonal and transient population of 78,000 persons not included. Seasonal and transient popula-tion is entirely in " Automobile-owning Population" segment.

-2/Automobile-owning population <. x1; des school population.

I i

l

-3/All school students regardless of cu-owning' status of l their household.

t 28

,w --- - _ -

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-. .. _ . . . - .- . . . . - - __ ~. .

V. THE EVACUATICN SEQUENCE FOR SEABRCCK STATION

- GENERAL CCNCIPT OF EVACUATICN The overall purpose of the evacuation is simply to remove the popula-tien of the EPZ as rapidly as possible. The evacuated pcpulation is -

. directed to reception centers, where it is temporarily ledged. Some of the evacuated population will go to the hcmes of nearby relatives and acquaintances. !

r Wherever possible, the evacuating population will leave the EPZ by means of private automobiles. Persons without automobile transportation will i

j be transported by transit vehicles, ambulances and other available t vehicles.

i In general, motorists will leave the EPZ by the most direct router that is, the shortest route out of the EP". Traffic direction at some key locations will help balance the traffic volumes en the evacuation routes.

Normal traffic flow will be observed, with streets cp e to all vehicles ,

and functioning in their usual manner.

3 In estimating evacuation times, the EPZ populatien is grouped according to how it evacuates: (1) auto owning population, (2) school population (3) non-auto owning population and (4) persons in institutions. .

Each of these groups follows a different sequence in evacuating: "

1 o the auto owning population, after receiving the notice to evacuate, assembles the family (except for children at school) at home, prepares for evacuating the home and drives out of the EPO. Non-residents (for example, beach visitors) simply assemble the group with which they are traveling, and leave the area.

t- 29

.. _ ~ _ . _ . . . _ . -_ _

r P

i o the school population is transported out of the EPZ directly i from the schools. School buses are used to evacuate this >

population.

o non-auto owning households prepare for leaving their heme, assemble at collection locations, and are then transported out of the EPZ in buses or other vehicles.

1 o persons in institutions - (hospitals, etc.) are prepared for i evacuation, then transported out of the EPZ in buses and ambulances. '

2 J

] POSSIBLE EVAC"ATICN TIME PERICDS ,

1 t

The length of time needed for evacuation of the Seabrook Station EPZ j will vary, depending on the time of day, day of week and season of year i

in which the evacuation occurs. Four possible time periods are identified:

o Nighttime

o Daytime on a-summer weekend (" Summer Sunday" case) o Daytime on a winter weekend o Daytime on a " winter weekday" case r i In estimating evacuation ; . the " worst cases" of these four time periods should be adopted; that u , evacuation. time estimates should reflect conditions likely to cause the longest evacuation times.

1 Nighttime Evacuation J l

I In a night evacuation, the notification process would be slowed by l people' having to wake up and comprehend the evacuation information being broadcast.. Additional time would be required to prepare vehicles for evacuation in the dark.- Cn the other hand, for most segments of

+

4

-30

.e.

the population, the families would be intact at the time of notification, since schools are not in session and relatively few employees are on the job.

Daytime en a Su==er Weekend (" Summer Sunday" Case)

In any daytime evacuation, the notification time is at a minimum, since

=ost people are awake and =any are already liste ting to radio and tele-vision broadcasts. Familes are = ore likely to be at the same location on weekends, since schools are not in session and relatively few persons are at work. Cutdcor recreation is at a peak during this season, and many non-residents are at the beach areas.

Daytime / Weekday Ivacuation (" Winter Weekday" Case)

Ouring a dayti=e/ weekday evacuation, a majority of the employed population would be on the job. During most of the year, schools are in session and the transportation of students beccmes a large issue in any evacuation.

For much of the populatien, a daytime / weekday evacuation creates additional action steps, since families must be assembled prior to leaving the h0=e and evacuating the EPZ. Also, during the daytime / weekday period, the like-lihcod of persons being away from home without a vehicle are greatest.

Critical Time Perieds .

For the evacuation of the Seabrook Station EPZ, the critical time period--

that is, the period for which evacuation is likely to require the mest time--is the "Su==er Sunday". During this period, the population and vehicle accumulation in the EPZ is at a maximum.

The next most critical time period is the " Winter Weekday" period.

During this period, the time needed to assemble family units is likely to be at its maxix.=1 Furthermore, the daytime / weekday periods raises issues 1 of school population evacuation which do not exist in other time periods.

1 l

31

- .-~ . , - - . . _ .

't ./

Separate evacuation time estimates are prepared for both of these time periods, i.e., for " Summer Sunday" and " Winter Weekday".

POPULATICN SEGMENTS TO BE EVACUATED As a first step in estimating the evacuation times for the Seabreck EPZ, its population is divided into segments. A separate time estimate is made for each of these segments. This method, by recognizing the various ways >

in which population leaves the EPZ, allows a more precise prediction of required times. The basis for the various population segments is HCW j that segment of population leaves the EPZ. Consequently, four population segments are identified:

(1) Nito ownine population, who evacuate by driving cut in private aute=cbiles. This population segment consists of all members of car-owning households, except children at school.

(2) School population; that is, all children at school. This population is evacuated directly from schcols, in school buses.

(3) Ncn auto-owning hcuseholds: all persons in households where a

- car is not reasonably available for evacuation. Some of this population is evacuated by friends and relatives. These not evacuated by friends or relatives assemble at collection points, and are evacuated by bus.

(4) Population in institutiens such as hospitals, nursing homes, j ails , etc. This population is evacuated directly from the ,

institution, by bus or special vehicle.

Family Units Families (excluding children in $chool) are evacuated as units. On weekdays, assembly of the family units involves members returning home 32 _

..l from their jobs, shepping, etc. Cn weekends, many families are already assembled and can immediately prepare to leave home. Non resident families (for example, beach visitors) are already assembled, and evacu-ate with almost no further preparation.

. EVACUATICN ACTICN STEPS b

For each pcpulation segment, the evacuation sequence consists of a series of action steps. These are clearly defined actions, performed in a predictable sequence (see Figure 7) .

Subdividing the evacuation process into these discrete steps improves the accuracy of the estimates of time needed for the entire evacuation.

In place of a single estimate of the entire evacuation process, for which data is not available, this process permits the estimation of times for each individual step, for most of which data is readily available.

Public Acencv and Private Steps Scme of the evacuation steps identified in Figure 7 are performed by public agencies. For all population groups, the " Evacuation Notice" action is the responsibility of public agencies. For those persons evacuated by means other than privately owned vehicles, public agencies have the additional responsibility for the actual evacuation steps for example, " Evacuate School Pcpulation in Buses", " Evacuate Non-Auto 1

Cwning Households in Buses", etc. For pcpulatica in institutions, the

" Mobilize Population" step is also a public agency responsibility.

Those action steps not the responsibility of public agencies are done at the initiative of the individuals being evacuated. For the auto cwning population, all steps after the initial " Receive. Broadcast Information" are private actions; that-is, they are initiated by the individuals being evacuated. Similarly, two of the steps in the. evacuation of non-auto owning households are private steps.

33

. . l

.1 es sxde for the time required for (1) receiving broadcast infor=ation, (2) leaving place of work, and so forth.

The times needed to ccmplete each step are not expressed as a single value of time, such as an average or a median value. Rather, the times required for each step are stated as the distribution of times, relating the fraction of the population completing a particular step to the elapsed time after notice to evacuate.

Time Recuired for a Series of Action Steps The total evacuation time is calculated by linking together the times required to ecmplete the individual steps. The resulting total times for evacuations are stated, as are the times for the individual steps, as a distribution of ti=es, showing the fraction of the population which completes the total evacuation process within a given amount of elapsed time.

Assignment of the Traf fic to._ t._he Evacuation Routes The traffic due to the evacuation of the auto owning households is

"'ssigned" (that is, distributed) to the available roads cut of the EP , as shcwn in *.he previous chapter. Celays due to this traffic are calculated, and the evacuation times are adjusted to reflect these delays.

EVACUATICN TIMES FCR CASE A: SUMMER SUNDAY Figure 12 shows the time needed to evacuate the population of the entire Seabrook Station IPZ under a su=mer weekend condition (that is, under Case A: Su=mer Sunday).

i l

The critical population element is the auto owning population; in other l l

words, it is this element of the population that establishes the total i

evacuation time. Other elements of the population (for example, popula- j 56

P D *D'3 D"kf e e . 11 a ,

ALL NON-BEACH POPULATICN ALL BEACH POPULATION EVACUATED WITHIN EVACUATED WITHIN 3 HOURS 25 MINUTES 6 HOURS to MINUTES AFTER START OF AFTER START OF EVACUATICN NOT*CE EVACUATICN NOTICE 100 ,

5 i C NON-BEACH I

< s0 PCPULATICN ,

=

b l SEACH i l l -a-. PCP ULATICN

$ 50 e ,

O i S :

-e I I 40

- f Q

i C l g 2C-C !

l 00 l. # ,

0:00 1:00 2:00 3:00 400 5:00 6:00 7:00 TIME AFTEll ShRY OF EVACUATION NOTICE (HCURS)

_ _ _ _ _ . . . _ _ _ . . _ ___ Figure 12. Evacuation Times: Case A, Summer Sunday 57

tion in institutions) can be evacuated in a shorter time than the auto owning population, provided that vehicles are available for their evacua-tion. Consequently, their evacuation does not add to the total evacua-tion time.

As indicated in Figure 12, there are two distinct components of the evacuation traffic under the Summer Sunday case (1) beach traffic population and (2) non-beach population. The ncn-beach population is cleared within 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months and 55 minutes after the start of notification.

The beach traffic, on the other hand, is not cleared until 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 10 minutes after the start of notification.

I Formatien of Traffic Congestion At numerous points within the Seabrock EPZ particularly in the beach areas, traffic backups (queues) will form during seme.part of the evacua-i tien process. These are caused as the auto owning populaticn ccepletes the necessary preparations to leave their hemes or the beach, and enters the street system at a rate greater than the capacity of that street system to carry them (Figure 12) . As a consequence, traffic begins to back up, starting at critical intersections (" bottlenecks") at which traffic demands are the greatest. Congestion then spreads rapidly from these critical intersections. Shortly after they first form, queues spread along arterial streets, blocking traffic attempting to feed in frem side streets. In the worst case, congestion spreads generally throughout the area, with all arterial and collector streets and even scme local streets blocked. At this point, numerous private and ccm- ,

mercial driveways are blocked.

During the period in which this congestion is occurring, the rate of evacuation is fixed by the capacity of the street system, and is.no longer . determined by the rate at which the population finishes prepara- l 1

tions to leave their households or the beach. Motorists leaving their 58

4 i_ .

c l homes and. entering the street system during such a period are simply 1

" stored" in traffi': queues in the street system. Under such conditions,

' increasing the speed of notification and the clearing of households and ,

$ beaches does not improve the total evacuation times, but rather merely puts more vehicles into the traffic congestion.

f Two possible levels of congestien are illustrated in Figure 13. In the less severe inst ance (upper diagram in Figure 13) the traffic queues end as the rate of vehicles entering the street system diminishes. At i this point, free traffic ficw is restored, and the rate of evacuation f is ence again determined by the rate at which the population ccmpletes preparations to leave home. This situation, occurring on most of the inland evacuation routes, results in a total evacuation time of 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months 45 minutes after the start of the notice to evacuate.

1 In the more severe example of cengestion (lower diagram in Figure 13) typical of beach area traffic, traffic queues are so large that they

)

continue even after all auto cwning households have left hem; and entered 3 the street system. Cnce started, this type of traffic congest' :n centinues until evacuation is complete.

Extent of Traffic Congestion T

4 Figure 14 illustrates the extent of traffic congestion and the length of delay during the evacuation period. These examples are focused en i evacuation routes in the beach area, where the maximum delays occur.

"'he level of congestion, the length of time spent in traffic backups and the length of these backups are unlike anything that the pcpulation of the Seabrock EPZ has encountered previously, and it is important that the dimensions of this congestion be understood:

f l

59

>- , -,_ _. . - , _ , - , - . - - _., --e-o - -- .. ,---- - -_ , - - . ,,v, , ,v-

. I i

3 A. CONGE STION ENDING dEFORE ALL AUTO OWNING POPULATION LEAVES HOMF

~.

O C 100

! l

$ . I 3 '

$ 40 EMDS AT A ~ RATE AT W HIC H .,

THIS P OIN T, m VEHICLES ENTER O STREET SYSTEM FREE FLOW l RESTORED e-2 l ( l 80 INDIC ATES 35 VERITY u ~

OF DELAY

$ I

'O \ RATE AT WHICH VEHICLES -

g CAN EV ACU ATE. QUE TO

C AP ACITY OF STREET

< l

- SYSTEM

$ 20 g o \ CONGESTION SEGINS l 1:30 2:00 2:30 3:00 3:30 4:00 TIME FROM START OF NOTIFIC ATION l

CONGESTION OONTINUING AFTER ALL AUTO-8.

OWNING POPULATIOte LEAVES HOME ALL V EHICL ES IN STREET SYSTEM

'00-l l

, .--- ,5 g s CONGESTION RATE AT W HIC H 3EVERITY '

ENO3 AFTER l So - VEHtCLES ENTER QF QELAY 'ALL POPUL A TIO N STREET JYSTEM I - HAS LEFT HOME 80 !

RATE AT WHi?H YEHICLES

% CAN EVACUATE 40 20 CONGESTION SEQlN3 1:30 2:00 2:30 $30 3:30 4:00

~

Figure'13. Traffic Congestion Analysis __

60

J

[Jh LOCATICN CF TgAFFIC cuEUE5 pg gugggg suMER N Yh: ,

I

,{ ,,, h ,;, , ,;33,, ,

UEU ,

g TO 5 MIL b pTcN PER HOUR- -

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N 7 #

96 ~

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's 80RTw SEaCH

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gAMPTOM BEACH ggAsROCK B 'g

, SEABqccx BEACH

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' $:- ;.2?^

Si:iR::::::;iE -

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[ SAbisauRY kd '

SAL $8Ugy SEACH

-., j;.:. , ,,, . ,"

2 1 ,\ ' # ..**i' .

.Z WITHIN THE CITY GF NEW80RYPORT, ABCUT 10 .8 . ^- I MILES OF QUEUE ARE .F- l OISTRIBUTED ON THE LOCAL STREET SYSTEM. '

(( l NEwouRyecRT i

i \

Figure 14. Trattic Congestion: Case A, Summer Sunday 61

.i o Iangth of delays: The maximum delay for the entire Seabroox Station EPZ will be experienced by traffic exiting from Salis-bury Beach. For a vehicle entering the end of the traffic

- congestien at its maximum, the delay will be 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months and 15 minutes. In other words, a vehicle entering the street system at the peak of the congestions will not move (or will scarcely move) for a period of 4 hcurs and 15 minutes. This is the maximum time, which represents c worst case. Celay times for 1

other motorists range downward frcm this maximum of 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months and 15 minutes; nevertheless, the majority of the Salisbury Beach pcpulation will have delay times in excess of 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months . .

The Hampton Beach traffic is next in order of length of traffic delay experienced, with a maximum delay of 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months and 15 3 minuten, This is followed by Seabrook Beach, with a maximum delay of 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months sad 45 minutes.

Cther significant delays occur at the more inland locations.

For example, fer the inland portions of Northampton, Hampton and Salisbury, the maximum delay is 30 minutes, while at Newburyport the maximum delay is 60 minutes.

o Lencth of Traffic Backup: In several 1ccations, the amount of traffic that is attempting to enter the street system exceeds the space available on the entire road system. In other words, there is not enough space on the streets to store the vehicles attempting to get onto the street systam. Consequently, many vehicles will not be able to leave their parking spaces, drive-ways, etc.

This situation is the most severe in the Hampten Beach area where a queue 0 backup) of 49 lane-miles of traffic is attempting I 1/ A lane-mile of traffic is one lane of traffic backed up for one

< mile. A lane-mile of traffic centains about 200 vehicles.

i t

62

to enter a road system of about 11 miles in length. Even if much of the road system were operated with two lanes outbound, there would still be space, on ene entire road system, for less than one-third of the vehicles r.tta=pting to enter it.

Next in terms of length of traffic backups are Salisbury Beach (27 lane-miles of traffic) and Seabrook Beach (11 lane-miles of traffic).

Cn the inland portions of the coastal tewns, the backups are about one mile for Hampton and North Hacpten, and no queue at all for Seabrook.

At the larger inland tcwns, significant queues are expected to fors. For example, 4 miles of backup will form at Nowburyport a about 7 miles will form in Amesbury. However, these backups are spread over numerous local streets, and are not concentrated on a single highway, as in the case of beach area congestion.

Traffic Congestien and Driver Behavior There is considerable uncertainty as to what might happen to driver behavior in 30 to 90 minute traffic backups under circumstances such as an evacuation. The existing evidence for this type of occurrence is sketchy and uneven. In scme more or less documented instances, such as evacuation after chemical spills or evacuation related to natural disasters, generally orderly traffic flow has been reported. On the other hand, experiences such as major snewfalls (even in regions accustemed to such type of weather) suggest that driver behavior deteriorates quite regularly under circumstances of 30 to 90 minute delays.

Scme specific motorist behavior problems that could be caused by delays of the length expected in the Seabrook EPZ evacuation include:

63

1, .

t I

o Creation of more lanes in the outbound directions; in effect, a one-way system out of the area,-as motorists impatient with

, thu length of queue simply begin using the left hand (that is, inbound) lanes for travel out of the area. This is not neces-sarily a poor strategy if planned, but could be chaotic if it occurs spontaneously.

Furthermore, if a two-lane flow must be returned to a single lane at some dcwnstream point, then there is no advantage in the two-lane ficw. To the contrary, the merging activity as the two lanes are ccabined into one will cause a loss in capacity relative I to a single smcochly flowing lane.

J j o 31ccking cross streets at intersections. This is a common type of traffic disorder, even under no=nal traffic' situations, and :

f it can almost certainly be predicted that this will happen under evacuation circumstances, particularly since at times the length 1 of queue will extend back through several intersections, and will fill me entire road system of the beach area.

I E i o Disregard of normal traffic control devices (such as signals, lane =arkings, signs, etc.) is a frequent consequer.ce of routine .

o traffic congestion such as that occurring at sportir..g events, traffic accidents, construction locations, etc. Disregard of traffic-control devices could be assemed to be even more wide-spread during evacuation of the Seabrook EPZ. Failure of traffic control causes a reduction of capacity, at a given location, to about 60-80 percent of the capacity that is obtained under well-disciplined traffic flow.1/

o Total traffic stoppage. In this type of failure, traffic is backed up through the entire network of intersections, and ne traffic can be discharged out of the tie-up. It is possible, 1/

- Goolsby, Merrell E., Influence of Incidents on Freeway Quality of Service, in Highway Research Record 4349, Traffic Flow, Capacity and Quality of Services,: National Academy of Sciences,1971.

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under this condition, that the total amount of traffic moved i eut of a given area (the beach, for example) becemes far less than that under conditions where traffic is flowing. In fact, no traffic at all may move for some periods.

i o Abandoning vehicles is frequently seen.in situations no worse than routine large snowfalls. If vehicles are abandoned along the roadways, or in the traffic lanes, they will seriously diminish the capacity of the roadway and cause bottleneck situa-tiens.

o Running out of fuel: It is quite likely that in any sort of traffic tie-up, a number of vehicles will find themselves running out of fuel, particularly since there is no time to fill cars with fuel before starting. In this situatien, aban-dened vehicles along the roadways seriously impair th._ capacities of those roads.

1 o Attempting to re-enter area: Cespite instructions to the con-trary, seme motorists will attempt to enter areas being evacuated, in order to gather fantly members, secure prcpe.ty, etc. Traffic caused by this activity will generate turning movements, could further reduce capacity at critical intersections and will ultimately be added to the total evacuating traffic.

In the event of spontaneous one-way operation, re-entering traffic wculd cause a chaotic situation.. In such a situation, even a few re-entering vehicles could result in the loss of an entire lane of outbcund traffic.

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, .EVACUATICN TIMES FOR CASE B: WI!CER WEEKDAY r T

Figure 15 shows the time needed to evacuate the population of the entire i

Seabrcok EPZ under.a working day during school hours (Case B: Winter We ekday).

The critical population element in this evacuation time is the auto-owning population; in other words, it is this element of the pcpulation that estaolishes the total evacuation time. Other' elements of the population (for example, population in institutions) can be evacuated in less time :

than the auto-owning population, provided only that vehicles are available

' for their transport. Consequently, their evacuation does not add to the total evacuation time.

4 As indicated in Figure 15, the entire EPO population is evacuated within

! 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months 40.ninutes after the start of notification.

Traffic Cer cestion in a Winter Weekdav Evacuation i

Traffic congestion cccurs en several evacuatien routes during a Wintar Weekday evacuatiin. Mcwever, under normal weather and traffic centrol conditions, .this tongestion dissipates prior to the time that all house-holds have left hem 3 and entered the street systam. (See upper diagram in Figure 13.) Conse uently, evacuation tima is determined by the rate at r which the population finishes preparations to leave cheir households, and is not determined by the capacity of the street system.

In a Winter Weekday evacuation,-the road system is operating at capacity for a substantial.part of the evacuation pericd. Any appreciable loss of capacity (for e cample, because of severe weather, uncontrolled traffic ficw, etc.) wecid cause evacuation times to be extended beyond the 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months

.40 minutes estimated above.

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ALL POPULATICN EVACUATED WITHIN 3 HOURS 60 MINUTES AFTER START Oc EVACUATION NOTICE 100 5

U SO 5

2 r

$ 60

! E o

=

4 $ 40 E

j 20 8

00 - ,

0 00 1:00 2>00 3,00 4,00 5800 6:00 7:00 TIME AFTC"4 START OF EVACUATION NOTICE (HOURS) ,

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Figure 15.' Evacuation Times: Case B, Winter Weekday 67

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i EVACUATION CF THE SCHCOL POPULATION f

The determining factor in the times for the evacuation of the school popu-j lation is mebili=ing the available school bus fleet. The school population can be' notified well in advance of the arrival of school buses. After e

notification, preparation to leave the school premises is almost immediate (stnilar to a routine fire drill) . Buses will be loaded immediately upcn arrival at the schools and will then travel directly out of the EPC.

A bus fleet large enough to carry the entire school population in a single trip is assumed in estimating these evac 2ation times. This fleet will be drawn from all districts within or partiy within the EP2. In addition, other buses will be drawn frem districts not within the EPZ but in the close vicinity of it.

IVACUATICN OF *HE MCN-AUTO IWNING HCUSEHOLOS 4

The determining facter in the rate of evacuation for the nca-auto owning population is the availability of buses for transporting this segment of the populawien. The non-auto owning population can be assambled at ,

collection points we?1 in advance of the arrival of 5uses for their evacuation. 3uses will be loaded Onmediately upon arriving at the collection points, will travel directly to the reception center, and will -

return to the cellsetion points for a second load.

A bus fleet sufficently large to evacuate the non-auto owning population in two trips is critical to achieving total evacuation ti=es estimated above (6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 10 minutes on a su:cer Sunday, and 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months 40 minutes on a Winter Weekday). If a sufficiently large bus fleet couJd not be mobili-sed, and a third trip cut of the EPZ were needed (even if by only a few buses), the total evacuation time for the non-auto owning population would increase and could beccme the critical (i.e., determining) element of the evacuation ti=e.

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Interestingly, a bus f.1.eet larger than that needed to carry the non-auto owning population in two trips provides only marginal savings in total 4

evacuation times. For example, a fleet large encugh to carry 75 percent of the non-auto owning population at one time would improve total evacuation 2

times by.only 10 minutes.

EVAC"ATICN CF THE POPULATICN n! INSTITUTICNS 1

The determining factor in the rate of evacuation for the population in institutions is the availability of buses and ambulances for transporting this segment of the population. The population in institutions can be

=obili:ed for evacuation well in advance of the arrival of buses for their evacuation. Buses would be loaded Onmediately upon arrival at the institu-tions, would travel directly to the reception centers, and would return to the institutions for a second load.

A bus (and ambulance) fleet large encugh to evacuate the population in institutions in two and three trips, respectively, is critical to achieving the totsi evacuation ti=es estL=ated above. If a sufficiently large bus and rebulance fleet could not be mobilised, and additional trips out of 1 the EPZ were needed (even' if only by a few vehicles) , the total evacuation 4 time for the population in institutions would increase and could become the critical (i.e., determining) factor in evacuation times.

SELEC'"IVE EVAC"ATICH CF AREAS WITHri THE EPZ Cepending on wind conditions and the nature of the release at the Seabrock Station, the selective evacuation of the EPZ might be reasonable. Evacu-ation times for reasonable ecmbinations of sectors within the EPZ are shown i in Figure 16.

Evacuations within the two-mile and five-mile radius.of tha plant could be accomplished in less time than evacuation of the entire EPZ, due primarily to the availability, as evacuation routes, of several north-south roads (for example,' US 1, State Route 1A) that would not be fully available to 69 I

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TRIGGERING EVACUATION SECTORS TIME CONDITIONS 2 /

\@ Y 1 DNLY j VA UATION

( g 0

s HOURS to MINUTES

)

/

e /

$$!?fk E 1 1,2 AND 3 s 9OURS 40 MINUTES

&@k g fuA L 07 i~ \

/

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' '\

fMile EVACUATION TO 1.2 AND 4 S' .5 HOURS lo MINUTES

@j '

R S ,

WIND 5

/

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/

EVACUATION TO 1,3 AND 5

' S' 6 HOURS 10 MINUTES 3

i" Figure 16. Selective Evacuation Times 70

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the two-mile and five-mile radius populations in the event of a full EP2 evacuation.

Two possible selective evacuation ecmbinations extend to the 10-mile radius:

1. Sectors 1, 2, and 4, a possible pattern in the event of a northwesterly wind.

2. Sectors 1, 3, and 5, a pattern in response to a southwesterly wind.

For the 10-mile selective evacuation which includes the Newburyport urban area, the total evacuation time is the same as for the evacuacion of the full EP2. This is because the maximum evacuation time fer the entire EP" is established by the level of traffic congestica in the Newburyport urban area, in ccmbination with the beach traffic. In a selective evacuation which in-cludes Newburyport, this same level of congestion and therefore same evacua-tion time prevail.

For the selective evacuarian to the 10-mile radius but not including the urban area cf Newcuryport, the evacuation time is significantly less than for the full EF", and is the same as for the two-mile radius evacuation. This is

=ainly a reflection of the lack of traffic cengestion in the northwest part of the Seabrcck Station EP2.

IMPACT OF 15-MINUTE NOTIFICATICN CN EVACUATICN TIMES For the critical time peried (Su==er Sunday) , a 15-minute notification would

=ake almost no noticeable i=provement in evacuation times over those esti=ated with the existing notification system in use (projected to be 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months 15 minutes, based on discussions with local officials). The evacuation ti=e for the Summer Sunday situation is detetained almost totally by the rate at which the beaches can be evacuated; speeding up the notification process, under these circum-stances, si= ply accelerates the rate at which motorists enter the existing traffic cengestion. However, in the Winter time, on both weekdays and week-ends, the evacuation time is controlled by the evacuee departure rate, and 71

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theretcre a reduction in notification time is reflected directly in the

, total evacuation time.

IMPACT CF SEVERE WEATHER CN EVAC"ATICN TIMES ,

3 Severe weather, in the form of a major winter storm, would lengthen the

, normal weather evacuation times to 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months and 30 minutes after start of notification (i.e., 40 minutes more than evacuatien times under normal weather conditions on a Winter Weekday).

1 This severe weather evacuation time assunes a slowdown in traffic but no loss in street capacity (i.e. , no lanes or streets blocked) . The impact of contingencies which cause loas of traffic capacity (i.e., blocked it.nes or entire roads) cannot be estimated without specifying the exact nature of the problem. In general, any loss of capacity on any =ajor evacuation route will cause major traffic problems throughout the evacuation pericd.

l 3CD'ARY CF IVACT.*,ATIIN TIMES Table 5 su=marises total evacuaticn times for:

)

o Summer Sunday and Winter Weekday cases.

i o Normal weather conditions.

o severe weather conditions.

o Evacuation in which a 15-minute notification is achieved.

o Selective evacuation of the two-mile' radius, five-mile radius, i

and 10-mile radius.

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EVACUATION TIMES FOR SEABROCK STATICN 3

1 Case A Case B Summer Sunday Winter Weekday 4

Normal Weather (15-Minute a Notification) 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 10 minutes 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months 40 minutes i

Normal Weather (Existing 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .55 minut3s Notification) 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 10 =inutes i

Severe Winter Weather

! (15-Minute Notification) (not applicable) 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months 30 minutes 2-Mile Jadius Selective i Evacuation (15-Minute l Notification) 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months 10 minutes (not estimated) 1 5-Mile Radius Selective Evacuation (15-Minute j Notification) 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months 40 minutes (not estimated) 10-Mile Radius Selective Evacuation to Nor.hwest (15-Minute Notification) 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months 10 minutes (not estimated) 10-Mile Radius Selective Evacuation to Southwest (15-Minute Notification) 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 10 minutes c.: t estimated) i 1

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PRCBLEM, ISSUES AND RECOMMENDATIONS Beach Traffic Congestion

. In a Summer Sunday evacuation at the beach area, traffic delay ranges up to 1 a maximum of 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months 15 minutes; i.e., a vehicle may be stopped for over 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months in traffic congestion.

Two possible actions can be taken to reduce the rate at which ve,hicles enter the street system, thereby reducing the length of traffic quetos and the amount of time spent in them by motorists:

1. Sequential evacuation of the beach area. Under this strategy, evacuation of the beach area would be staged, with one section cleared before evacuaticn of the next section begins.

Sequential evacuation can be managed through selective notifi-i cation of the population, detailed broadcast information, and

t traffic control.

I

' Sequential evacuation does not in itself. reduce the total evacuation time. However, it reduces the a=ount of time spent in vehicles by the evacuating population, and it also reduces

{

j _the chance of a' chaotic breakdown in traffic control.

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2. Sheltering on the beach. Some of the population may be sheltered in their residences on the beach, thereby reducing the number of vehicles attempting to enter the road system.

Sheltering.could be done as part of a sequential evaluation, in which sheltered population evacuates as congestion diminishes.

l j The radiological exposure trafe-off of sheltering vs. waiting in a vehicle stopped in traffic congestion is outside the scope of this analysis. However, available information suggasts that l exposure risk is high for persons in vehicles. ;

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t Effective Evacuation Planning i

For the Summer weekend case, an effective evacuation (i.e. , one which is well planned and in which effective traffic control is secured) will take 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and 10 minutes. An ineffective evacuation, with resources not properly mobilized and with uncontrolled traffic flow, will require from I

10 hours1.157407e-4 days 0.00278 hours 1.653439e-5 weeks 3.805e-6 months 30 minutes to 14 hours1.62037e-4 days 0.00389 hours 2.314815e-5 weeks 5.327e-6 months 40 minutes for completion.

3 The difference between controlled and uncentrolled evacuations ranges from 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months 20 minutes to 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months 30 minutes. This difference in evacuation times can be considered as the incrament of improvement that proper planning j

) and securing of resources buys.

l The difference in resource costs between effective and ineffective evacu-ations has not been esti=ated. However, it appears that this cost difference

! is small. For example, the local resources used -- firemen,-policemen and

) civil defense -- are about the same regardless of whether or not the evacu-stion is effective. The most significant cost difference between effective and ineffective evacuations is probably in the area of preparation, specif-ically in the amcunt and quality of the planning work that goes into the evacuation plan and into the securing of resources.

More Use of I-95 The capacity of I-95, as it presently operates, cannot be fully used in an evacuation. Entry ramps are limited in number and not located ideally for evacuation.

f Additional emergency-only ramps could be added to 7.-95, southbound as well as northbound. These ramps, similar to maintenance-vehicle ramps already I in use, would involve minimal constcuction and would not be used under normal conditions, i

75

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Bunes for the Transit-Dependent Population The dominating factor in the evacuation time for the transit-dependent pcpelation (i.e., the non-auto owning population and the population in institutions) is the availability of transit buses and ambulances. The estimated evacuation times in this report assumes an availability of vehicles such that half of the ambulatory transit-dependent pcpulation can be carried at one time. This assumption of bus availability, however, is far in advance of the actual nu=ber of buses secured by the local plans.

The consequences of a smaller fleet are substantial. As the fleet drops below the size necessary to acco=modate one-half the ambulatory transit-dependent population at once, a third round-trip by some buses becomes necessary, sharply raising the time needed for evacuation of that population.

In view of the large bus requirements for evacuating the transit-dependent pcpulation, it is reco= mended that:

1. Sources of buses be clearly identified as the local preparedness plan develops, and that a fleet adequate to carry the transit-dependent population in two round-trips be secured (90-90 buses).

2. Reception areas for the transit-dependent population be located as close to the EPZ as possible to minimize the travel time.

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VIII. VEHICLES AND MANPCWER REQUIRED FOR EVACUATING THE SEABRCCK STATION EPZ INTRCDUCTICN

?do resources needed.for the evacuation of the Seabrock Nuclear Station EPZ are:

(1) Vehicles A. school buses, transit buses and ambulances for trans-porting persons not having access to a private vehicle for evacuation.

3. traffic centrol and towing vehicles (2) Manpower A. drivers for school buses, transit buses and ambulances

3. tow trud. cperators C. traffic centrol persennel D. superviscry and coordination personnel VEHICLE REQUIEiEICS School Buses A total of 220 school buses are required for the evacuation of the schcol ,

population in the EPZ. This bus requirement is based on the transportation, in a single trip, of all school population frcm the EPZ.

School buses will be obtained from all districts within or partly within the EPZ, and from other school distr' fyb within about a 20-mile distance from.the EPZ (that is, within a C 9ti .a rMius of the Seabrcok Station).

Privately-owned fleets as we), er 7 ~ icly cwned fleets will be mobilized.

77 l 1

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.? es Transit Buses Between 89 and 90 transit buses are required for the evacuation of the non-auto cwning households and persons in institutions. The range in this requirement is due to the variatien that might occur in the number of persons frca non-auto owning hcuseholds that will be evacuated in privat ;. autcmobiles of friends, neighbors, or relatives. The bus require-ment of 80 to 90 vehicles is based on transporting the non-auto owning population and the population in institutions in two trips per vehicle; that is, after carrying the first load of passengers to a reception center, each bus returns to the EPZ for a second load.

Transit buses will be mcbilized frcm private cen: mon carrier fleets located in the vicinity of the EPZ, and frem public transit fleets in the Ports-acuth and Besten urban areas.

Ambulances Between 80 and 130 ambulances are required for the evacuation of the non-ambulatory population in institutions. The range in this require-ment is d'te to (1) fluctuations in the size of the non-ambulatory populaGon in the EPZ (2) uncertainties as to the fraction of non-ambu-latory population that might be evacuated in regular buses and (3) range in the fraction that might be sheltered within the EPZ rather than evacuated frera it.

l The requireme-t for 80 to 130 ambulances is based on each ambulance

=aking three trips out of the EPZ.

Ambulances will be mobilized from all sources within the EPZ, including hospitals, nursing homes, rescue units, and private carriers. Ambu-l lances will also be mobilized from all available sources within a 20-25 mile area surrounding the EPZ.

78

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Traffic Control and Towing Vehicles

.A total of 77 critical traffic control points have been identified for the routes assumed in this evacuation time estimate. Each of these loca-tions requires a traffic control officer on duty for most of the duration of the evacuation process. Since radio communication with these traffic control points is critical, a need for 77 radio dispatched vehicles is identified for traffic control use at critical locations.

Between 30 and 50 towing vehicles will be needed during most of the evacuation time period. Tow trucks will remove disabled or abandoned vehicles which are blocking evacuation routes.

Tow trucks will be mobilized frem the fleet now based within the EPZ, as well as frem i::: mediately surrounding areas.

MANPOWER TdQUIREMENTS School Bus, Transit Bus and Ambulance Drivers Operation of the vehicle fleets as discussed above will require 220 school bus drivers, 80 to 90 transit bus drivers and 80 to 130 ambulance

' drivers.

Traffic Control Providing traffic control at the 77 critical intersections in the EPZ will require 77 to 120 traffic centrol personnel. The range.is due to.

the possibility that more than a single traffic control person will be

.needed at some locations.

T w Truck Cperators Operation of the tow truck fleet as described above will require 30 to 50 tow truck operators.

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Suoerviserv and ccordinating Personnel A total of 360 to 430 persons are needed to conduct the evacuation at the local (town) level. Activities include operation of the notification system, supervision of traffic control, operation of collection points for non-a. 2 owning pcpulation, manning of local evacuation headquarters and confirmation of evacuation. This personnel will consist of the local pre-paredness officers and designated staff.

SUMMARY

OF VEHICLE AND MANPCWER REQUIREMENTS Table 9 su w a-izes the vehicle and manpower requirements for the evacuation of the Seabrook Station EPZ.

It is stressed that these requirements are for only those activities related directly to transportatien and do not include requirements for many other evacuation activities. For example, vehicle and =anpower requirements for such non-transportation activities as notification, public safety, sheltering activity, or operation of the reception centers are not included

~

in the requirements suararized in Table B.

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TABLE 9 A

VEHICLE AND MANPCWER REQUIREMENTS FOR EVACUATING

.SEABROCK STATICN EPZ RANGE CF RESOURCES FOR EVACUATION CF ENTIPE SEABRCCK RESCURCE STATICN EPZ VEHICLES SCHCOL BUSES 220 buses TRANSIT BUSES 80-90 buses AMBULANCES'20-139 ambulances TRAFFIC CONTROL 77 police cruisers TCWING 30-50 towing vehicles MANPOWER SCHOCL BUS ORIVERS 220 drivers TRANSIT BUS DRTIERS 80-90 drivers AMBULANCE CRIVERS80-130 drivers TRAFFIC CONTROL 77-120 traffic cfficers TCWING CPEPATCRS 30-50 towing operators SUPERVISCRY AND' 360-430 persons CCCRDINATICN PERSCNNEL 1

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'IX. CCNFIRMATION OF EVACUATION CCNFIRMATION PROCSSS The confirmation process measures how effectively the evacuation is being accomplished. Confirmation is conducted by the local civil defense agencies, beginning at about the time at which evacuation was estimated to be complete.

Confirmation of evacuation is essential for security reasons, to assure

~

that all population has left the area, and to assist those persons having difficulties in evacuating.

PCSSICLE APPRCACHES TO CCNFIRMING THE EVACUATICN CF THE EPZ Confirmation of evacuation may be approached in various ways:

o Active or passive: Proof of evacuacion may require scme action by the evacuee, or, en the other hand, may be acccmplished through other means, without any action on the part of the evacuee.

o Extent of coverage of the population: The ccnfirmation process may include 100 percent of the population (that is, every household) or it may be on a sampling basis, with scme fraction of the total population surveyed, o Cetailed method of confirmation: A variety of detailed methods of confirmation is possible. Cne such method is for the evacu-ating household to leave some indication (sign, flag, symbol, etc.) at their residence upon evacuating. Security personnel would patrol through the EP::, monitoring the progress of the-evacuation and the rate at which the residents are leaving.

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Another method of confirmation is to have monitors call households by telephone and ascertain that they have left the area.

These methods may be supplemented by monitoring the cutbound ficw of traffic and recording the cumulative number of people leaving the area.

RECC.v24 ENDED CONCEPT FCR CCNFIFJ1ING EVACUATICN IN THE SEABRCCK STATICN EPZ Considering the population, road system and other characteristics of the Seabrook Station EPZ, a confirmation concept having these features is recommended:

o Passive--The compliance problems with active methods of confirma-tien (that is, which require acticn on the part of the evacuees) are large, and substantial nc=bers of the evacuation pcpulation would not ccmply with any such plan. Furt .ler=cre , the size of the pcpulation in the Seabrook Station EPZ dictates majer admini-strative effort in simply monitoring the confirmation indicaters.

For this reason, a passive confirmation concept (that is, one not requiring any action by the evacuee) is strcngly recem= ended.

o Sampled--It is not realistic to plan any ccnfirmation system for the Seabreck Station IPZ that is based en 100 percent confirma-tion that each of the 41,000 households has evacuated. To do this would require either (a) an unreasonable number of monitors to cover all households in the EPZ cr (2) a length of time required that extends far beycnd the. expected maximum evacuation times.

Consequently, a confirmation concept based en sampling (rather than full co nting) of the EPZ population is strongly reccmmended.

It is stressed that the accuracy of a sampled approach is quite likely to be as good, or even better, than an active system with its attendant problems of non-ccmpliance by the evacuating households.

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o Confirmation by Telechone -- One possible method for accomplishing -a passive, sampled confirmation of evacu-ation is through a telephone. sampling method. In such a method, monitors call a randemly selected group of households to confirm that evacuation has occurred. If continuing information on a cross-section of households is desired, this' sampling could.be repeated at regular intervals.

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