NUREG/CR-7002

SAND2010-0016P

Criteria for Development of Evacuation 

Time Estimate Studies

Manuscript Completed: September 2011

Date Published: November 2011

Prepared by: J. Jones and F. Walton

Sandia National Laboratories

B. Wolshon

Louisiana State University

Sandia National Laboratories

Albuquerque, NM 87185

Operated by

Sandia Corporation

for the U.S. Department of Energy

J. Laughlin, NRC Technical Lead

Prepared for:

Division of Preparedness and Response

Office of Nuclear Security and Incident Response

U.S. Nuclear Regulatory Commission

Washington, DC 20555-0001

NRC Job Code R-3139
ii

Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin 

Company, for the United States Department of Energy’s National Nuclear Security 

Administration under contract DE-AC04-94AL85000.
iii

ABSTRACT

The evacuation time estimate (ETE) is a calculation of the time to evacuate the plume exposure 

pathway emergency planning zone (EPZ), which is an area with a radius of about 10 miles 

(16 km) around a nuclear power plant. The ETE is primarily used to inform protective action 

decision-making and may also be used to assist in development of traffic management plans to 

support an evacuation. The ETE should be developed to provide the time to evacuate

90 percent and 100 percent of the total population of the EPZ. The 90 percent ETE provides 

the time value that would typically be used to support protective action decisions. This 

document provides guidance for the development of ETEs, including those associated with 

staged evacuation protective actions. The document also identifies the importance of using 

approved emergency response plans and existing traffic control information to reflect the 

expected response actions during an emergency. Guidance on the review and update of ETEs 

is also included. The format and guidance provided herein will support consistent application of 

the ETE methodology, and can serve as a template for the development of ETE studies. 

Applicants and licensees may propose an alternative method for complying with the associated 

relevant portions of the emergency preparedness regulations, which the NRC would need to 

deem acceptable if they provide the basis for the findings required for the issuance or 

continuance of a permit or license by the Commission.

Paperwork Reduction Act Statement

The information collections contained in this NUREG are subject to the Paperwork Reduction 

Act of 1995 (44 U.S.C. 3501 et seq.), which were approved by the Office of Management and 

Budget, approval numbers 3150-0011 and 3150-0151.

Public Protection Notification

The Nuclear Regulatory Commission (NRC) may not conduct or sponsor, and a person is not 

required to respond to, a request for information or an information collection requirement unless 

the requesting document displays a currently valid OMB control number.
iv
v

TABLE OF CONTENTS

Page

ABSTRACT............................................................................................................................... iii

TABLE OF CONTENTS .............................................................................................................v

EXECUTIVE SUMMARY .......................................................................................................... vii

ACKNOWLEDGMENTS............................................................................................................xi

ACRONYMS............................................................................................................................ xiii

PREFACE.................................................................................................................................xv

1.0 INTRODUCTION.............................................................................................................1

1.1 Approach.........................................................................................................................2

1.2 Assumptions....................................................................................................................3

1.3 Scenario Development ....................................................................................................4

1.4 Evacuation Planning Areas..............................................................................................7

2.0 Demand Estimation.....................................................................................................11

2.1 Permanent Residents and Transient Population............................................................11

2.2 Transit Dependent Permanent Residents......................................................................13

2.3 Special Facility Residents..............................................................................................14

2.4 Schools .........................................................................................................................14

2.5 Other Demand Estimate Considerations........................................................................15

2.6 Summary of Demand Estimation ...................................................................................16

3.0 Roadway Capacity.......................................................................................................17

3.1 Roadway Characteristics...............................................................................................17

3.2 Capacity Analysis ..........................................................................................................18

3.3 Intersection Control .......................................................................................................19

3.4 Adverse Weather...........................................................................................................20

4.0 Development of Evacuation Times.............................................................................21

4.1 Trip Generation Time.....................................................................................................21

4.2 ETE Modeling................................................................................................................25

4.3 Evacuation Time Estimates for the General Public ........................................................27

5.0 Other Considerations..................................................................................................31

5.1 Development of Traffic Control Plans ............................................................................31

5.2 Enhancements in Evacuation Time ...............................................................................31

5.3 State and Local Review.................................................................................................31

5.4 Reviews and Updates....................................................................................................32

5.5 Reception Centers and Congregate Care Centers ........................................................33
vi

5.6 New Reactors................................................................................................................33

5.7 Early Site Permits..........................................................................................................34

6.0 Glossary.......................................................................................................................35

7.0 References...................................................................................................................37

APPENDICES

A. Roadway Network Characteristics ...............................................................................A-1

B. Evacuation Time Estimate Evaluation Criteria .............................................................B-1

FIGURES

1-1 Vicinity Map.....................................................................................................................1

1-2 Keyhole Evacuation.........................................................................................................7

1-3 Emergency Response Planning Areas ............................................................................7

2-1 Population by Sector .....................................................................................................12

2-2 Shadow Area for Keyhole Evacuation ...........................................................................15

3-1 Roadway Network Identifying Nodes and Segments .....................................................18

A-1 Roadway Network Nodes and Segments ....................................................................A-2

TABLES

1-1 ETE Comparison .............................................................................................................2

1-2 General Assumptions ......................................................................................................3

1-3 Evacuation Scenarios......................................................................................................4

1-4 Evacuation Areas for a Staged Evacuation Keyhole........................................................8

1-5 Evacuation Areas for a Keyhole Inclusive of the 2-Mile Zone ..........................................9

3-1 Weather Capacity Factors .............................................................................................20

4-1 Special Facilities ETE....................................................................................................24

4-2 Schools ETE..................................................................................................................25

4-3 ETEs for a Staged Evacuation Keyhole.........................................................................29

4-4 ETEs for a Keyhole Evacuation Inclusive of the 2-Mile Zone .........................................29

A-1 Roadway Characteristics.............................................................................................A-2

B-1 ETE Review Criteria Checklist.....................................................................................B-1
vii

EXECUTIVE SUMMARY

The evacuation time estimate (ETE) is a calculation of the time to evacuate the plume exposure 

pathway emergency planning zone (EPZ), which is an area with a radius of about 10 miles 

around a nuclear power plant (NRC, 1980). Section IV of Appendix E to 10 CFR Part 50 

requires that an analysis of the time required to evacuate be provided for various sectors and 

distances within the plume exposure pathway EPZ for transient and permanent residents. The 

ETE is primarily used to inform protective action decision-making and may also be used to 

assist in development of traffic management plans to support an evacuation. The ETE is used 

as an information tool, and therefore, no minimum evacuation time must be achieved. The 

guidance in NUREG-0654/FEMA-REP-1, Rev. 1, “Criteria for Preparation and Evaluation of 

Radiological Emergency Response Plans and Preparedness in Support of Nuclear Power 

Plants,” Criterion J.10, provides additional information regarding the use of ETE results (NRC, 

1980). ETEs should be used by licensees in the development of offsite protective action 

recommendations and by offsite response organizations (OROs) when making offsite protective 

action decisions.

This guidance document details the process for the development of ETEs for four population 

segments including:

• Permanent residents and transient population;

• Transit dependent permanent residents;

• Special facility residents (e.g., hospitals, prisons, nursing homes, etc.); and

• School populations.

Guidance is provided on developing evacuation demand, preparation activities, ETE modeling

and reporting results. Some of the key criteria developed in this document include:

• Development of ETEs for the staged evacuation protective action;

• Emphasis on the use of existing emergency preparedness programs when developing 

the ETE;

• Use of traffic simulation modeling;

• Consideration of shadow evacuations in the analysis;

• Verification of commitment of resources, such as buses and ambulances, etc.;

• Consideration of the evacuation tail; and

• ETE updates.

Research in evacuations has shown that implementation of staged evacuations can be more 

beneficial to the public health and safety (NRC, 2007). This guidance document establishes an

approach to develop ETEs for a staged evacuation.

It is important to use the information found in approved emergency plans when developing an 

ETE study to ensure that the results represent the expected response from authorities. This 

guidance document emphasizes the use of existing emergency planning methodology when 

developing the ETE including:

• Use of existing registration programs for people with disabilities and those with access 

and functional needs who do not reside in special facilities;

• Modeling of planned or approved evacuation routes;

• Use of approved traffic control plans in the analysis; and
viii

• Use of planned bus routes for analysis of the transit dependent population evacuation.

This guidance describes the benefits of using traffic simulation modeling to calculate the ETE 

and establishes measures of effectiveness (MOEs) for use in the review of this ETE element. 

When an ETE is developed without the use of a traffic simulation model, supporting data and 

calculations consistent with this guidance document should be provided. The guidance also 

establishes the need to include a 20 percent shadow evacuation in the analysis. A shadow 

evacuation is defined as an evacuation of people from areas outside an officially declared 

evacuation zone. The shadow population is considered in the analysis to account for any effect 

of this population group impeding the evacuation of those under evacuation orders.

This guidance emphasizes the importance of verifying the committed resources, such as buses 

and ambulances, required to support evacuation of the transit dependent and school

populations, as well as people with disabilities and those with access and functional needs. The 

number and location of available resources directly affect the ETE, and lack of available 

resources has been a problem in some large scale evacuations (NRC, 2008a).

ETEs provide information for use in the formulation of a licensee’s protective action 

recommendation and the ORO’s protective action decisions. It is important that the time to 

evacuate the public is clearly understood to ensure the most appropriate protective action is 

implemented. ETEs that overestimate or underestimate evacuation time are not helpful in 

making the best protective action decision. Research of existing evacuations (NRC, 2005a; 

NRC, 2007) shows that a small percentage of the public, about 10 percent, takes a longer time 

to evacuate. This 10 percent is defined as the “evacuation tail.” Planning is established to 

evacuate all of the public; however, decision makers should use the 90 percent ETE values 

when developing procedures for the implementation of protective action decisions. The 

90 percent value informs decision makers of the estimated time to evacuate the vast majority of 

the public, and the 100 percent ETE informs decision makers on the likely time for the EPZ to 

be fully evacuated. Therefore, the time to evacuate 90 and 100 percent of the population 

should be provided in the ETE study.

Section IV of Appendix E to 10 CFR Part 50 requires ETE updates when the EPZ permanent 

resident population increases such that it causes ETE values to change by 25 percent or 

30 minutes, whichever is less, from the licensee’s currently NRC approved or updated ETE. 

Additionally, in the unlikely event that the conditions of an EPZ are changed significantly due to 

natural phenomena hazards or other reasons (e.g., a bridge collapse), an interim update to the 

ETE is recommended. This guidance document also identifies the importance of developing 

ETE studies using traffic control plans agreed upon by the local authorities.

Use by Applicants and Licensees

Applicants and licensees1 may voluntarily2

 1 In this section, “licensees” refers to licensees of nuclear power plants under 10 CFR Parts 50 and 52, and 

the term “applicants” refers to applicants for licenses for nuclear power plants under 10 CFR Parts 50 and 

52 and all applicants for early site permits with complete and integrated emergency plans submitted under 

10 CFR Part 52.

use the guidance in this document to demonstrate 

compliance with the ETE analysis development required by the NRC in 10 CFR Part 50, 

Appendix E, Section IV. Each ETE analysis report should be formatted consistent with this 

2 In this section, “voluntary” and “voluntarily” means that the licensee is seeking the action of its own accord, 

without the force of a legally binding requirement or an NRC representation of further licensing or 

enforcement action. 
ix

template and submitted to the NRC under 10 CFR 50.4 for review to confirm the completeness 

of the ETE analysis. Methods or solutions that differ from those described in this document may 

be deemed acceptable if they provide sufficient basis and information for the NRC staff to verify 

that the proposed alternative demonstrates compliance with the appropriate NRC regulations. 

Licensees may use the information in this document for actions which do not require NRC 

review and approval. Licensees may use the information in this document or applicable parts to 

resolve regulatory or inspection issues. 

Use by NRC Staff 

During regulatory discussions on plant specific operational issues, the staff may discuss with 

licensees various actions consistent with guidance in this document, as one acceptable means 

of meeting the underlying NRC regulatory requirement. Such discussions would not ordinarily 

be considered backfitting. However, unless this document is part of the licensing basis for a 

facility, the staff may not represent to the licensee that the licensee’s failure to comply with the 

guidance in this document constitutes a violation. 

If an existing licensee voluntarily seeks a license amendment or change and (1) the NRC staff’s 

consideration of the request involves a regulatory issue directly relevant to this document and 

(2) the specific subject matter of this document is an essential consideration in the staff’s 

determination of the acceptability of the licensee’s request, then the staff may request that the 

licensee either follow the guidance in this document or provide an equivalent alternative process 

that demonstrates compliance with the underlying NRC regulatory requirements. This is not 

considered backfitting as defined in 10 CFR 50.109(a)(1) or a violation of any of the issue 

finality provisions in 10 CFR Part 52. 

The NRC staff does not intend or approve any imposition or backfitting of the guidance in this 

document. The NRC staff does not expect any existing licensee to use or commit to using the 

guidance in this document, unless the licensee makes a change to its licensing basis. The NRC 

staff does not expect or plan to request licensees to voluntarily adopt this document to resolve a 

generic regulatory issue. The NRC staff does not expect or plan to initiate NRC regulatory 

action which would require the use of this document. Examples of such unplanned NRC 

regulatory actions include issuance of an order requiring the use of this guidance document, 

requests for information under 10 CFR 50.54(f) as to whether a licensee intends to commit to 

use of this guidance, generic communication, or promulgation of a rule requiring the use of this 

document without further backfit consideration.

Additionally, an existing applicant may be required to adhere to new rules, orders, or guidance if 

10 CFR 50.109(a)(3) applies. 

If a licensee believes that the NRC is either using this document or requesting or requiring the 

licensee to implement the methods or processes in this document in a manner inconsistent with 

the discussion in this section, then the licensee may file a backfit appeal with the NRC in 

accordance with the guidance in NUREG-1409 and NRC Management Directive 8.4.
x
xi

ACKNOWLEDGEMENTS

In support of this activity, the NRC Technical Leader, Jeff Laughlin, provided the technical 

leadership to ensure this project met the needs of the emergency preparedness program. NRC 

staff including Randy Sullivan, Eric Schrader, Bob Moody, Falk Kantor, and Steve LaVie 

provided technical insights supporting key elements of the criteria. Joe Jones, Sandia National 

Laboratories, led the project team and the development of the ETE criteria. Fotini Walton 

performed research for Sandia National Laboratories to support development of the criteria. Dr. 

Brian Wolshon, Louisiana State University Hurricane Center, supported development of the ETE 

criteria and provided technical support and consultation based on his extensive experience in 

evacuation and transportation analyses.
xii
xiii

ACRONYMS

ASCE American Society of Civil Engineers

CFR Code of Federal Regulations

COL Combined License

DOT Department of Transportation

EAS Emergency Alert System

EMO Evacuation Management Operations

EPZ Emergency Planning Zone

ERPA Emergency Response Planning Area

ESP Early Site Permit

ETE Evacuation Time Estimate

FEMA Federal Emergency Management Agency

FHWA Federal Highway Administration

GIS Geographical Information System

HCM Highway Capacity Manual

LOS Level of Service

MOE Measure of Effectiveness

NPP Nuclear Power Plant

ORO Offsite Response Organization

PAR Protective Action Recommendation

TRB Transportation Research Board
xiv
xv

PREFACE

Advancements in the development of ETE modeling along with the knowledge gained through 

research of large scale evacuations (NRC, 2005b; NRC, 2008a) have contributed to the need to 

update the guidance for ETE development. Additionally, NUREG/CR-6953, Volume I, “Review 

of NUREG-0654, Supplement 3, ‘Criteria for Protective Action Recommendations for Severe 

Accidents’” (NRC, 2007), concludes that a staged evacuation protective action provides greater 

benefit than a standard radial keyhole evacuation. Guidance is provided herein on developing 

staged evacuation ETEs. This guidance document provides a template for the development 

and updating of ETE studies. It is intended to assist users in identifying contributing factors to 

the ETE and provide a methodical process for development of data and performance of ETE 

calculations.

Section 1 provides an introduction to the ETE, describes the characteristics of the EPZ, 

establishes general assumptions, and identifies the evacuation scenarios to be evaluated. 

Section 2 provides detail for consideration in developing demand estimates for permanent 

residents and transients, transit dependent populations, special facilities, schools, and 

quantifying a shadow evacuation. Section 3 describes the approach for evaluating the roadway 

capacity and establishes values for use in adverse weather calculations. Section 4 discusses 

the process for developing trip generation times and provides detail on information that should 

be included in an ETE study when traffic simulation modeling is used. Section 5 identifies other 

considerations including development of a traffic control plan, potential enhancements to the 

ETE, State and local review, reviews and updates of the ETE, when to include the effect of 

reception centers on the ETE, new reactors, and early site permits. Appendix A of the 

document provides an example of roadway characteristics to be provided, and Appendix B 

provides ETE review criteria.

Use of the format and criteria provided herein will support consistent application of ETE 

methodology, thereby facilitating a consistent review of initial or updated ETE studies. 

Licensees should use the ETE when developing procedures that support making offsite 

protective action recommendations and for developing those recommendations. OROs should 

use the ETE when developing offsite protective action strategies and when making offsite 

protective action decisions.
xvi
1

Figure 1-1 Vicinity Map

1.0 INTRODUCTION

The objective of this section is to provide a description of the emergency planning zone (EPZ), 

and to describe the general approach used to meet the requirements for developing an 

evacuation time estimate (ETE). Section IV of Appendix E to 10 CFR Part 50 requires that an 

analysis of the time required to evacuate be provided for various sectors and distances within 

the plume exposure pathway EPZ for transient and permanent residents. To address this 

requirement, licensees must develop an ETE, which is a calculation of the time required to 

evacuate the 10-mile plume exposure pathway EPZ (NRC, 1980). The ETE is used to inform 

the protective action decision-making process and to assist in the development of traffic 

management plans to support an evacuation. The licensee should use the ETE when 

developing procedures that support making protective action recommendations (PARs), and 

offsite response organizations (OROs) should use the ETE when developing offsite protective 

action strategies.

This NUREG/CR provides 

detailed information and 

guidance for use in 

developing or updating an 

ETE study. The format 

and criteria provided herein 

are intended to support 

consistent application of 

ETE methodology and will 

facilitate NRC review of 

initial or updated ETE 

studies. The format of the 

sections, tables, and 

figures presented herein 

should be used, as 

appropriate, for the specific 

EPZ.

To establish the framework 

for the review, the ETE 

study begins with an 

introduction section. A 

description of the EPZ 

should be provided 

including the nuclear power plant (NPP) site location and any unique characteristics of the EPZ. 

A map of the plume exposure pathway EPZ depicting the roadway network, population centers, 

political jurisdiction boundaries, and significant topographical features such as rivers, lakes, 

State parks, etc., should be included. The information may be provided on one or more maps 

depending on the complexity of the EPZ and the ability to clearly identify the necessary 

features. Figure 1-1 provides an example of a vicinity map of a hypothetical EPZ. Legends 

should be provided for relevant symbols, acronyms, and abbreviations used in the presentation.

When updating an ETE study it is beneficial to provide an overview of changes that have 

occurred since the development of the previous study. A comparison of the updated and

previous ETEs should be included when updating an existing ETE. Table 1-1 identifies 

information that is useful in comparing the ETEs.
2

Table 1-1 ETE Comparison

ETE Element Previous ETE Updated ETE

Permanent Residents

- Total population

- Vehicle ratio

Transit dependent population

- Total population

- Number of buses

- Number of ambulances 

Transient population

- Total population

Special Facilities 

- Total Population

- Number of buses 

- Other transportation resources 

Schools

- Total student population

- Number of buses

Shadow evacuation percent estimated

Special Event(s)

- Population

- Location

- Duration

Adverse Weather (rain, snow, ice, fog)

Evacuation Model – name and version

Scenarios

Assumptions

The availability of traffic simulation models that support ETE calculations has increased 

considerably in recent years. The U.S. Department of Transportation has sponsored the 

“Evacuation Management Operations (EMO) Modeling Assessment: Transportation Modeling 

Inventory” which is available to support the selection of an appropriate model for use in 

evacuation analysis (DOT, 2007). Also, the Federal Highway Administration (FHWA) has 

developed a toolbox for use by analysts in modeling roadway networks (FHWA, 2004a). To 

address the use of modeling in the analysis, this guidance document identifies measures of 

effectiveness (MOEs) that will be used in the review of ETE studies. The ETE development 

should include a description of the key inputs, assumptions, outputs, and computational 

processes that are included in, or result from, the simulation. When an ETE is developed 

without the use of a traffic simulation model, supporting data and calculations should be 

developed consistent with the approach provided herein.

1.1 Approach

Evacuation analysis is based on moving the population away from the hazard in the most 

expedient manner practical within the constraints of the roadway network. This generally 

equates to a radial dispersion away from the hazard. ETEs are developed with consideration of 

when an event may occur, weather conditions, traffic volume, and other unique considerations 

of the EPZ. A well defined approach will ensure that key elements are addressed. Care should 

be taken when using conservative values, such as “worst case” values, to ensure that the 

analysis does not result in an aggregate of all “worst case” values as this is not the intent of the 

ETE. Methods used to address data uncertainties should be described.
3

The approach should include a description of:

• The process used in development of the ETE;

• Meetings with planners, emergency managers, and local authorities, as related to the 

resolution of issues affecting the ETE;

• Field surveys of roadways and traffic control systems;

• Information sources used to develop demographic data;

• The traffic control plans used in the analysis; and

• Evacuation modeling used for the analysis.

1.2 Assumptions

The planning basis for the ETE should include the assumption that evacuation is ordered 

promptly and no early protective actions have been implemented. Use of this planning basis 

allows the ETE to be calculated beginning with the initial notification to the public. It is 

recognized that most States have planning in place for implementation of early protective 

actions, such as evacuating schools prior to the general public, when time would allow. 

Concurrent events that could initiate evacuations on their own, such as hurricanes, need not be 

assumed. For those sites where EPZs overlap, the ETE need only consider an evacuation of 

the NPP that is the focus of the study.

General and site specific assumptions should be provided to support the analysis. Assumptions 

must be technically sound, be quantified when possible (NRC, 2005a), and have a basis. 

General assumptions that are appropriate for use in the study are provided in Table 1-2.

Table 1-2 General Assumptions

1. The ETE is measured from the time that instructions were first made available to the 

public within the EPZ (e.g., initial emergency alert system [EAS] broadcast).

2. Mobilization of the public begins after initial notification.

3. Schools and special facilities receive initial notification at the same time as the rest of 

the EPZ.

4. Evacuation time ends when the last vehicle has exited the EPZ.

5. Most vehicles at each residence will be used in the evacuation.

6. Background traffic is on the roadway when initial notification occurs.

7. A 50 percent capacity is appropriate for buses used in the evacuation of the 

population dependent upon public transportation.

8. Buses used to evacuate schools and special facilities are loaded to capacity.

9. Shadow evacuation of 20 percent of the public occurs to a distance of 15 miles from 

the NPP.

Additional assumptions that are specific to a section of the analysis, such as roadway capacity, 

should be included in the appropriate section of the ETE study.
4

1.3 Scenario Development

Scenarios are developed to identify combinations of variables and events to provide ETEs 

under varying conditions to support protective action decisions. Scenarios include season, day 

of the week, time of day, weather conditions, special events, roadway impact, or other

circumstances that should be assessed. Multiple scenarios are intended to ensure that the ETE 

results encompass a reasonable range of potential evacuation situations for the specific site. 

Scenarios generally assume that residents evacuate from their home; however, it should not be 

assumed that all residents are at home when the initial notification is received. A daytime 

scenario should be developed for representative site-specific conditions during the work day. 

The evening scenarios should represent the timeframe when residents are generally at home 

with fewer residents dispersed within the EPZ. The number of scenarios may vary depending 

on site-specific considerations, and the 10 scenarios identified in Table 1-3 are expected.

Table 1-3 Evacuation Scenarios

Scenario Season Day Time Weather

1 Summer Midweek Daytime Normal

2 Summer Midweek Daytime Adverse

3 Summer Weekend Daytime Normal

4 Summer Midweek and Weekend Evening Normal

5 Winter Midweek Daytime Normal

6 Winter Midweek Daytime Adverse

7 Winter Weekend Daytime Normal

8 Winter Midweek and Weekend Evening Normal

9 Special Events Normal

10 Roadway Impact Midweek Daytime Normal

A description of each scenario used in the study should be provided similar to those provided 

below.

1. Summer Midweek Daytime (normal): This scenario represents a typical normal weather 

daytime period when permanent residents are generally dispersed within the EPZ 

performing daily activities and major work places are at typical daytime levels. This scenario 

includes assumptions that permanent residents will evacuate from their place of residence;

schools are closed and students are at summer activities; hotel and motel facilities are 

occupied at average summer levels; and recreational facilities are at average summer

daytime levels.

2. Summer Midweek Daytime (adverse): This scenario represents an adverse weather 

daytime period when permanent residents are generally dispersed within the EPZ 

performing daily activities and major work places are at typical daytime levels. This scenario 

includes assumptions that permanent residents will evacuate from their place of residence;

schools are closed and students are at summer activities; hotel and motel facilities are 

occupied at average summer levels; and recreational facilities are at average summer

daytime levels.

3. Summer Weekend Daytime (normal): This scenario represents a typical normal weather 

weekend period when permanent residents are both at home and dispersed within the EPZ 

performing typical summer weekend activities. This scenario includes assumptions that 

permanent residents will evacuate from their place of residence; schools are closed and 

students are at home or with their families; work places are staffed at typical weekend 
5

levels; hotel and motel facilities are occupied at average summer weekend levels; and 

recreational facilities are at average summer weekend levels.

4. Summer Midweek and Weekend Evening (normal): This scenario represents a typical 

normal weather midweek and weekend evening period when permanent residents are 

generally at home with fewer dispersed within the EPZ performing evening activities. This 

scenario includes assumptions that permanent residents will evacuate from their place of

residence; schools are closed and students are at home; work places are staffed at typical 

evening levels; hotel and motel facilities are occupied at average summer levels; and

recreational facilities are at average summer evening levels.

5. Winter Midweek Daytime (normal): This scenario represents a typical normal weather 

weekday period during the winter when school is in session and the work force is at a full 

daytime level. This scenario includes assumptions that permanent residents will evacuate 

from their place of residence; students will evacuate directly from the schools; work places 

are fully staffed at typical daytime levels; hotel and motel facilities are occupied at average

winter levels; and recreational facilities are at winter daytime levels. The number of 

permanent resident vehicles may be reduced appropriately in this scenario to account for 

the number of students at school within the EPZ, because the buses used for evacuation of 

students account for the vehicle load.

6. Winter Midweek Daytime (adverse): This scenario represents an adverse weather 

weekday period during the winter when school is in session and the work force is at a full 

daytime level. This scenario includes assumptions that permanent residents will evacuate 

from their place of residence; students will evacuate directly from the schools; work places 

are fully staffed at typical daytime levels; hotel and motel facilities are occupied at average

winter levels; and recreational facilities are at winter daytime levels. The number of resident 

vehicles may be reduced appropriately in this scenario to account for the number of 

students at school within the EPZ, because the buses used for evacuation of students 

account for the vehicle load.

7. Winter Weekend Daytime (normal): This scenario reflects a typical normal weather winter 

weekend period when permanent residents are both at home and dispersed within the EPZ,

and the work force is at a weekend level. This scenario includes assumptions that 

permanent residents will evacuate from their place of residence; schools are closed and 

students are at home; work places are staffed at typical weekend levels; hotel and motel 

facilities are occupied at average winter weekend levels and recreational facilities are at 

winter weekend levels.

8. Winter Midweek and Weekend Evening (normal): This scenario reflects a typical normal 

midweek and weekend evening period when permanent residents are home and the work 

force is at a nighttime level. This scenario includes assumptions that permanent residents 

will evacuate from their place of residence; schools are closed and students are at home;

work places are staffed at typical nighttime levels; hotel and motel facilities are occupied at 

average winter levels; and recreational facilities are at winter evening levels.

9. Special Events (normal): This scenario should reflect a special event activity where peak 

tourist populations are present within the EPZ. Assumptions made should reflect the 

timeframe in which the special event occurs. The population attending the event should be 

developed considering both transients and permanent EPZ residents who may be in 

attendance to avoid double-counting residents. The remaining permanent resident 
6

percentage, those not attending the event, will be assumed to evacuate from their 

residence. Work places will be staffed at typical levels; hotel and motel facilities are 

occupied at peak special event levels; and recreational facilities are at appropriate levels 

based on the event and time of year.

10. Roadway Impact Midweek Daytime (normal): The intent of this scenario is to represent a 

variety of conditions that may impact a roadway segment such as construction, flooding, 

vehicle accidents, etc. The roadway impact scenario should assume that during a summer 

midweek normal weather daytime scenario, one segment of one of the top five highest 

volume roadways will be out of service and unavailable to evacuees. An alternative to 

removing one roadway segment from use is to analyze the effect of a single outbound lane 

being shut down on an interstate highway. This analysis is conducted to understand the 

potential impact of such an event and to support the development of a traffic control plan by 

identifying areas where OROs may want to consider additional emergency planning such as 

the pre-positioning of response vehicles (e.g., tow trucks). The ETE for this scenario is not 

typically used in protective action recommendations or decisions.

1.3.1 Staged Evacuation

Evacuation research has shown that implementation of a staged keyhole evacuation can be 

more beneficial to the public health and safety than the normal keyhole evacuation (NRC, 

2007). A staged evacuation is where one area is ordered to evacuate while adjacent areas are 

ordered to shelter in place until directed to evacuate. When making protective action 

recommendations and decisions that include a staged keyhole evacuation, it is necessary to 

understand the ETE for this protective action. The following description of a staged keyhole 

evacuation is expected in the ETE study; however, site-specific PAR logic must also be 

addressed in the ETE study.

 

For each scenario, an estimate of the time to complete a staged keyhole evacuation is needed 

to support protective action decision-making. A discussion should be included on the approach 

used in the development of a staged keyhole evacuation. This analysis involves evacuating the 

0-2 mile zone while the 2-5 mile zone is under a shelter-in-place order. When approximately 

90 percent of the 0-2 mile zone has cleared the 2 mile zone boundary, based on the ETE, the 2-

5 mile zone would be loaded onto the evacuation network. The 2-5 mile residents enter the 

roadway network as the 0-2 mile population is passing through the area. During the time 

required for the 0-2 mile zone to evacuate, the 2-5 mile zone may be assumed to be preparing 

to evacuate, potentially reducing the trip generation time elements for this area. The analysis 

combines the time to evacuate the 0-2 mile zone with the time to evacuate the 2-5 mile keyhole 

area. A shadow evacuation of 20 percent should be included in this analysis as described in 

Section 2.5.2.

The shelter time of residents within the 2-5 mile zone would correspond to the ETE for 

90 percent evacuation of the 0-2 mile zone. The ETE value for the 0-2 mile 90 percent 

evacuation that will be used in response procedures is the estimated value obtained from the 

ETE document. It is not based on actual movement of vehicles during an evacuation.
7

1.4 Evacuation Planning Areas

The ETE is typically developed based upon the EPZ response planning areas. These areas are 

commonly referred to as Emergency Response Planning Areas (ERPAs), but may also be 

referred to as subareas, protective action areas, protective action zones, or other site specific

terminology. For purposes of this document, the term 

ERPA will be used; however, local terminology is 

appropriate and acceptable. ERPAs are defined as 

local areas within the EPZ for which emergency 

response information is provided. These areas are 

typically defined by geographic or political boundaries 

to support emergency response planning and may 

not conform to a precise 10-mile radius from the NPP 

(NRC, 1980).

ETEs should be developed for the complete 

evacuation of the following:

• 0-2 mile zone; Figure 1-2 Keyhole Evacuation

• 2-5 mile zone for a staged evacuation;

• 0-5 mile zone;

• Affected ERPAs necessary to support site-specific PAR logic (i.e., keyhole based on 

wind direction as 

shown in Tables 1-4 

and 1-5); and

• Complete EPZ.

Protective actions are 

implemented at the ERPA 

level. For those sites where 

ERPAs are large and 

encompass areas out to 

5 miles, the analyses, 

including the staged 

evacuation, should be based 

on the existing ERPAs. 

ERPA configurations do not 

need to be revised to 

facilitate the ETE analysis.

The analyses are performed 

using a keyhole evacuation 

as the basis. The term 

keyhole evacuation is used 

because the area evacuated Figure 1-3 Emergency Response Planning Areas

resembles a keyhole,

including a 360 degree area around the site with a two-mile radius, and continuing in a 

downwind direction, typically out to 5 miles from the NPP as shown in Figure 1-2. The keyhole 

includes the downwind sector and adjoining sectors on each side. The calculation of the ETE 

for a keyhole evacuation previously included the 0-2 mile zone; however, this guidance now 
8

separates the time for the 0-2 mile zone and the 2-5 mile zone to support protective action 

decision making for a staged evacuation. Analysis of keyhole evacuations that include the 0-2 

mile zone may still be performed, but these should be in addition to the staged evacuation 

analysis.

Evacuation areas are developed by assuming a plume travels in a fixed wind direction, and an

ETE is calculated for all of the ERPAs within the plume sector and at least the two adjoining

sectors. Figure 1-3 provides an example of an EPZ and generic ERPAs. To implement an 

initial keyhole evacuation, the 2-mile radius and affected downwind sectors would be evacuated 

to 5 miles. The affected downwind sectors in this example are the SSW and the adjacent S and 

SW sectors. All of the ERPAs encroached upon by these sectors would be evacuated.

Development of a full suite of ETEs requires that this process be repeated for each sector 

rotating around the EPZ until ETEs are calculated for all wind directions and scenarios.

In the example displayed in Figure 1-3, for a wind direction from the NNE to the SSW, the 2-mile 

zone includes only ERPA A and the 5-mile downwind sectors encroach upon ERPAs B and C, 

which would also be evacuated. Therefore, Table 1-5, shows the affected ERPAs are A, B, 

and C. For the ETE study, a map identifying the ERPAs should be provided along with a table 

identifying affected ERPAs for each wind direction.

As indicated in Table 1-4, ETEs are developed for each wind direction around the EPZ. When 

additional ETEs are developed for the keyhole, inclusive of the 2-mile zone, the format in 

Table 1-5 is appropriate. ETEs for the transit dependent population, special facilities, and 

schools are developed separately.

Table 1-4 Evacuation Areas for a Staged Evacuation Keyhole

Affected 

ERPAs Area A B C D E F G H I J K L

A 2 mile ring X

A thru F 5 mile ring X X X X X X

A thru L Full EPZ X X X X X X X X X X X X

Evacuate 2 to 5 miles downwind

Wind Direction 

(from)

Affected ERPAs

A B C D E F G H I J K L

BC N X X

BC NNE X X

BCD NE X X X

BCD ENE X X X

CD E X X

CD ESE X X

D SE X

DF SSE X X

DE S X X X

DEF SSW X X X

DEF SW X X

EF WSW X X

BF W X X

B WNW X X

B NW X

BC NNW X X
9

Table 1-5 Evacuation Areas for a Keyhole Inclusive of the 2-Mile Zone

Affected 

ERPAs Area A B C D E F G H I J K L

Evacuate 2-mile zone and 5 miles downwind

Wind Direction

(from)

Affected ERPAs

A B C D E F G H I J K L

ABC N X X X

ABC NNE X X X

ABCD NE X X X X

ABCD ENE X X X X

ACD E X X X

ACD ESE X X X

AD SE X X

ADF SSE X X X

ADEF S X X X X

ADEF SSW X X X X

AEF SW X X X

AEF WSW X X X

ABF W X X X

ABF WNW X X X

AB NW X X

ABC NNW X X X
10

This page intentionally left blank.
11

2.0 DEMAND ESTIMATION

The objective of this section is to detail the process for developing an estimate of the number of 

people to be evacuated. The NRC’s regulations in 10 CFR 50.47(b)(10) require that “a range of 

protective actions has been developed for the plume exposure pathway EPZ for emergency 

workers and the public.” The public includes all persons located within the EPZ, including 

residents, transients, people with disabilities and those with access and functional needs, and 

any other member of the public. Demographic data, together with information and assumptions 

on population groups support an estimate of the public and corresponding vehicles that will be 

evacuating the area. Demand estimation for the following four population segments should be 

developed:

1. Permanent Residents and Transient Population – Permanent residents include all 

people having a residence in the area. The transient population includes tourists, 

shoppers, employees, etc., who visit but do not reside in the area.

2. Transit Dependent Permanent Residents – Permanent residents who do not have 

access to a vehicle or are dependent upon help from outside the home to evacuate.

3. Special Facility Residents – Residents of nursing homes, assisted living centers, and 

those confined to hospitals, jails, prisons, etc.

4. Schools – All private and public educational facilities within the EPZ. Colleges and 

universities should be assessed on a case-by-case basis, recognizing that college 

students typically have access to a vehicle.

Demand estimates for these four population groups are developed separately to account for all 

of the public within the EPZ.

2.1 Permanent Residents and Transient Population

The number of permanent residents should be estimated using U.S. Census Bureau data 

adjusted as necessary for growth. Along with census data, local data may be used for 

population estimates. The population values used in the ETE should be developed for the year 

the ETE is prepared. The permanent resident population group is divided into two subgroups 

including:

1. Residents having available private transportation.

2. Transit dependent residents (dependent on others for transportation).

The distribution of permanent resident and transient populations should be provided in a format 

similar to Figure 2-1 with total populations provided for each sector. The rings and sectors of 

this figure may be extended to 15 miles to show the shadow populations.

2.1.1 Permanent Residents with Vehicles

An estimate of persons per vehicle should be provided. An estimate of 1 to 2 people per vehicle 

is typical. Values within this range should be used for the permanent population, unless site 

specific information supports the use of lower or higher values.
12

2.1.2 Transient Population

The transient population includes people temporarily visiting the area such as tourists, 

shoppers, employees who do not reside within the EPZ, etc. A list of facilities that attract 

transient populations should be developed, and peak and average attendance for these facilities 

should be listed. The use of average attendance values, by season, is generally acceptable. 

For example, the summer average weekday population for beach areas would be used for 

summer weekday scenarios, and average weekend population would be used for weekend 

scenarios.

The transient population should be itemized and totaled as appropriate for each scenario. For 

example, motel capacities may be full for evening scenarios, but empty during daytime 

SSE

SE

ESE

E

ENE

NE

NNE

N

W

S

SSW

SW

WSW

NNW

NW

WNW

Population

Miles

Subtotal 

by Ring

Cumulative 

Population

0-2

2-3

3-4

4-5

5-6

6-7

7-8

8-9

9-10

10-EPZ

Boundary

Figure 2-1 Population by Sector

0-2 

Miles
13

scenarios when tourists are visiting parks or other areas. The distribution of the transient 

population should be provided in a format similar to Figure 2-1. Care should be taken not to 

double-count transient populations. To avoid double-counting transients and permanent 

residents, indicate the percent of permanent residents of the EPZ assumed to be at parks, 

shopping, or other locations. The number of people per vehicle should be identified. A value of 

2.5 people per vehicle is typical, but this may vary by type of facility or location. A basis should 

be provided if higher vehicle occupancy rates are used. Large employers, defined as those with 

50 or more employees working a single shift, should be listed and include the number of people 

per vehicle.

2.2 Transit Dependent Permanent Residents

An estimate is needed for the time to evacuate those residents that do not have access to a 

vehicle. Special services that may be needed to support the evacuation of these residents must 

be considered (NRC, 1980) and identified within the ETE study. Surveys are helpful in 

identifying the site specific demographics of this population group, including the number of 

individuals and specialized transport needs. This population group may include:

• Households with no vehicles;

• Households with unsupervised latchkey children;

• Households with one vehicle that is at work and would not return;

• Households where residents have limitations on driving (e.g., elderly who do not drive at 

night or do not drive distances of more than a few miles); and

• Households dependent on specialized transportation such as wheelchair vans or 

ambulances.

Local and county emergency plans should be reviewed to identify if plans are in place to provide 

transportation to transit dependent residents during an evacuation. Where local plans exist, 

these should be used in developing the ETE. Data from local and county emergency planning 

registration programs should be used as a first order planning tool to support the demand 

estimate, but should not be used as the only source of data.

Previous research (NRC, 2008b) and data reviewed on existing ETEs indicate a range of about 

3 to 10 percent of EPZ permanent resident populations may be transit dependent. It is 

recognized that a portion of the population will rideshare during an evacuation, leaving the area 

with friends, neighbors, or relatives, and it is acceptable to assume that up to 50 percent of 

residents without vehicles will rideshare. This value is based on results of a national telephone 

survey conducted of EPZ residents (NRC, 2008b) which indicated more than 50 percent of 

residents would offer a ride to individuals waiting for transportation. Empirical data obtained 

from the widely studied Mississauga, Canada evacuation in 1979 (IES, 1981) also supports a 

value of 50 percent. If a higher value is used, a basis should be provided. Assuming that 

50 percent of transit dependent persons rideshare suggests that 1.5 percent to 5 percent of the 

EPZ permanent resident population may require transportation. A basis should be provided for 

use of values lower than 1.5 percent.

The capacity of municipal buses is based on adults, and the capacity of school buses is based 

on children. Considering that residents are evacuating with their belongings, including clothing, 

medicines, pets, etc., a reasonable estimate for buses is 50 percent of the stated seating 

capacity (NRC, 2008a) with no credit taken for standing room capacity. The capacities 

assumed for buses and other transportation should be identified and if an estimate higher than 
14

50 percent capacity is used, a basis for the estimate should be provided. Care should be taken 

not to double-count resources when calculating transportation needs for populations dependent 

on public transport and the transportation needs for special facility residents. The availability of 

transportation resources and drivers should be confirmed.

A subset of transit dependent residents includes people with disabilities and those with access 

and functional needs that live independent of a special facility. A recent telephone survey of 

residents living within EPZs found that six percent of respondents said they, or someone in their 

household, would need assistance to evacuate (NRC, 2008b). Information on households with 

residents dependent on specialized transportation such as wheelchair vans or ambulances

should be developed and quantified separately.

A summary of the total number of vehicles (e.g., buses, ambulances, specialized transport 

vehicles) available to support the evacuation of transit dependent residents, as well as people 

with disabilities and those with access and functional needs, not residing in special facilities 

should be provided. This will support the determination of how many evacuation runs may be 

needed.

2.3 Special Facility Residents

Special facility residents are those who reside in special facilities and are dependent upon 

facility personnel for transportation in an emergency. This includes, but is not limited to, 

hospitals, nursing homes, jails, and prisons. Special facility personnel are counted in the 

special facility population group. The process for obtaining special facility data should be 

described and typically includes contacting each facility. A list of special facilities, including the 

type of facility, location, and population, should be provided. The number of wheelchair and 

bedbound individuals should be identified. The average number of patients typically at the 

facility should be used. There may be unique situations where, after extensive efforts to obtain 

data on facilities, information is not available and assumptions must be used. In such instances, 

assumptions must be well documented and have a basis. For instance, considering similar 

facilities, such as nursing homes, an estimated capacity might be based on beds per square 

foot of the facility and should be comparable to other nursing homes in the area.

When evacuation cannot be accomplished with a single bus run, additional bus runs should be 

clearly indicated. Resources needed to evacuate special facilities typically include buses, vans, 

ambulances, automobiles, drivers and specially trained staff. Specially trained staff may include 

medical support or security support for prisons, jails, and other correctional facilities. The 

number and capacity of all vehicles needed to support the evacuation should be provided. Care 

should be taken not to double-count resources when calculating transportation needs for 

populations dependent on public transport and the transportation needs for special facilities. 

The availability of resources and drivers should be confirmed.

2.4 Schools

State and local emergency response plans typically include early protective actions for 

evacuation of schools prior to the general public if time allows. However, the development of 

ETEs should consider that school evacuations begin with the same initial notification provided to 

the general public. Schools present a unique issue with the expectation that some students

may be picked up by parents, relatives, or friends which may reduce the student population 

requiring bus transportation. A list of schools, including name, location, student population, and 
15

Figure 2-2 Shadow Area for Keyhole Evacuation

transportation resources required to support the evacuation should be provided. The source of 

the school population values should be identified.

In many areas high school students drive to 

school, and these students would be 

expected to evacuate in their personal 

vehicles. Busing for high school students 

may be reduced to reflect the number of 

students that drive as estimated by school 

staff. For elementary and middle schools, 

transportation resources should be based 

on 100 percent school capacity. Discussion 

should be provided on the assumptions for 

evacuation of school staff. When 

evacuation cannot be accomplished with a 

single trip, the need for return trips should 

be clearly indicated.

2.5 Other Demand Estimate 

Considerations

As described below, demand estimates 

should also be considered for peak 

populations during special events within the EPZ, shadow evacuations for the population 

extending out to 15 miles from the NPP, and for the background and pass through traffic within 

the EPZ.

2.5.1 Special Events

Special events occur within most EPZs and can attract large numbers of transients to the EPZ 

for short periods of time. Special events might include Fourth of July celebrations, Christmas 

parades, sporting events, or any number of activities that bring large populations into the EPZ. 

These events frequently define the peak tourist population that is to be included in the study 

(NRC, 1980). All special events that draw a large group of transients should be listed in the 

ETE with the estimated population, duration, and season of the event. However, only one 

special event that encompasses the peak tourist population needs to be analyzed as described 

below.

The total attendance for an event may provide information that is useful in development of the 

ETE but may not need to be considered as the demand estimation used. For instance, a 

weekend festival that draws 100,000 people over the duration of the event may not need to be 

assessed as an evacuation of 100,000 people. The average hourly or daily attendance may

provide a better evacuation number than the total population of the festival. For events where 

the attendees arrive and depart at relatively the same time, such as a sporting event, the total 

values are appropriate for use. To avoid double-counting transients and permanent residents, 

indicate the percent of permanent residents of the EPZ assumed to be at special events.
16

2.5.2 Shadow Evacuation

A shadow evacuation occurs when people outside of any officially declared evacuation zone

evacuate without having been instructed to do so. Shadow evacuations are considered in 

developing the demand estimation because the additional traffic generated has the potential to 

impede an evacuation of the EPZ. A shadow evacuation of 20 percent of the permanent 

resident population, based on U.S. Census Bureau data, should be assumed to occur in areas 

outside of the evacuation area being assessed extending to 15 miles from the NPP as shown in 

Figure 2-2. The 20 percent value is static to support a standardized assessment. A shadow 

evacuation would likely occur in a graded manner with the potential for a 20 percent shadow to 

occur from the areas that are closer to the declared evacuation area, decreasing with distance 

away from the affected area.

Population estimates for the shadow evacuation in the 10 to 15 mile area beyond the EPZ 

should be provided by sector. The loading of the shadow population onto the roadway network 

should be applied consistent with the trip generation time developed for the permanent resident 

population beginning when the evacuation of the 0-2 mile area begins. It is not necessary to 

estimate a shadow population for transient or special facility populations.

2.5.3 Background and Pass Through Traffic

Background and pass through traffic contribute to the demand estimation. Background traffic is 

defined as vehicles on the roadway when the initial notification occurs and consists of both 

residents and transients within the EPZ. It is important to consider that these individuals may be 

on the roadway within the EPZ at the beginning of an emergency and the ETE should include 

time for activities needed to return home, when appropriate, and then evacuate. Pass through 

traffic includes vehicles that enter the EPZ roadway network and ‘pass through’ prior to the 

establishment of access control points. In some EPZs, this may account for a significant 

volume of vehicles. The volume of vehicles should be representative of the average daytime 

traffic within the EPZ. Values may be reduced for nighttime scenarios. It is appropriate to 

assume that pass through traffic will stop entering the EPZ about 2 hours after initial notification 

when access control points have been established.

2.6 Summary of Demand Estimation

The assessment of the demand estimation will provide the total number of people and vehicles 

to be evacuated for each of the population groups including permanent residents with vehicles, 

transit dependent permanent residents (those who require specialized vehicle transportation 

and those who only require bus transportation), transients, special facilities, schools, shadow 

population, and background and pass-through demand. A summary table should be provided 

that identifies the total populations used in the analysis for each scenario, and a separate 

summary table should be provided that identifies the total number of vehicles by population 

group for each scenario. These values should represent the input values used in the traffic 

simulation modeling.
17

3.0 ROADWAY CAPACITY

The objective of this section is to identify the methods and data used in the assessment of 

roadway capacities. The capacity of a roadway is defined as the maximum rate at which 

vehicles can be expected to traverse a section of roadway during a given time period under 

prevailing roadway, traffic, and control conditions. Roadway capacity influences evacuation 

travel time particularly as traffic demand approaches or exceeds capacity. For this reason, a 

detailed capacity analysis is important. Capacity analysis is performed through the application 

of processes and equations established in the U. S. Department of Transportation’s Highway 

Capacity Manual (HCM) and augmented as appropriate for consideration of saturated flow 

conditions. As roadways become saturated, the HCM methodologies are not as well developed, 

and the analysis is best performed using traffic simulation models, which use numerical 

techniques to predict performance of traffic behavior. The method used to assess roadway 

capacity should be discussed.

3.1 Roadway Characteristics

Roadway characteristics are needed for proper depiction of the evacuation transportation 

network. Roadways should be categorized by functional class to identify the types of roadways 

used in the analysis. Local or regional terminology may be used for the roadway classes, and 

the following classes should be identified if present:

• Freeways or Interstates;

• Freeway ramps;

• Major arterials;

• Minor arterials;

• Collectors; and 

• Local roadways.

In all cases, a field survey of the key routes within the EPZ should be performed to validate 

existing mapping and obtain roadway characteristics and information for use in the analyses. At 

a minimum, the following information should be obtained:

• Number of lanes;

• Lane and shoulder width;

• Grade changes of more than about 4 percent;

• Left turns in lane group;

• Right turns in lane group;

• Narrowest roadway segments on evacuation routes;

• Roundabouts or rotary intersections;

• Toll gates and associated lane channelization;

• Intersection queuing capacities;

• Posted speed limits; and

• Areas where frequent flooding of roadways occur.

A legible map of the roadway system that identifies node numbers and segments used to 

develop the ETE similar to Figure 3-1 should be included. An electronic version of the map may 

be provided to allow enlargement as needed to support a detailed review of the nodes and 

segments of the roadway network. Depending on the complexity of the EPZ and the number of 

nodes and segments, the map may be presented in quadrants or other sectors to provide the 
18

Figure 3-1 Roadway Network Identifying Nodes and Segments

necessary clarity. A table of roadway characteristics should be presented in a format similar to 

that provided in Appendix A, “Roadway Network Characteristics.”

3.2 Capacity Analysis

The processes outlined in the HCM for two lane highways, multi-lane highways and freeways 

are used to determine the capacity of roadway segments by accounting for lane width, lateral 

clearance, heavy vehicles, etc., through the use of adjustment factors (TRB, 2000). However, 

many of the computational approaches used in the HCM break down as the roadway capacity is 

exceeded. Because this is a prominent condition during evacuations, traffic simulation modeling 

is used to assess traffic behavior. These models can better assess saturated flow where 

evacuation time becomes more dependent on the ratio of demand to capacity (v/c ratio) under 

the conditions and characteristics of the roadway network and the interactions between 

individual vehicles on the roadway.

The approach used to calculate the roadway capacity for the transportation network should be 

described in detail and should discuss important factors that are expressly used in the modeling, 

particularly those associated with the control and/or interruption of flow within the network. An 

approach that provides a more detailed analysis of key routes, such as evacuation routes, is 

suggested. Such an approach would include applying field acquired data to routes designated 

as evacuation routes. Routes that are not designated evacuation routes must also be 
19

evaluated, but field estimates in lieu of field measurements may be appropriate for these 

roadways. The capacity analysis should expressly state where field information is utilized in the 

ETE calculation and how it was acquired.

3.3 Intersection Control

The efficiency of roadway networks is frequently constrained by intersection capacity which is 

influenced by intersection control. Important characteristics of intersections include the number 

of approach lanes for through traffic, left and right turn lanes, and effective green time, which is 

the time that is used by vehicles to enter the intersection at the saturation flow rate. A 

discussion should be provided regarding how intersection characteristics are represented within 

the evacuation model. A list of intersections should be provided that includes the total number 

of intersections that were modeled with unsignalized control (e.g., stop signs), signalization, or 

traffic control personnel who physically direct traffic.

When developing the ETE, local agencies should be contacted to understand whether special 

signal timing plans exist for emergency conditions. Where these emergency condition timing 

plans exist, and are current, this information should be used in the analysis. A detailed 

description of the approach to modeling intersections should be provided. In particular, this 

should include the signal cycle timing, green time allocation to the constituent approaches, and 

other control variables such as whether signals work within a coordinated corridor or are 

coordinated across the network.

A key objective of traffic modeling is to best represent the expected traffic flow under evacuation 

conditions. The analysis approach should not attempt to optimize traffic flow through 

intersections. All signalized intersections should be included in the traffic simulation modeling; 

however, it is not practical or necessary to obtain individual traffic signalization timing for every 

intersection, because signal timing often changes throughout the day depending on traffic flow. 

Traffic simulation modeling should consider the following types of intersections:

• Unsignalized;

• Fixed time signals;

• Actuated signals; and

• Manned traffic controlled intersections.

Unsignalized intersections, such as those featuring stop or yield control, must be included. 

Fixed time signals provide a constant effective green time through the intersection for the 

primary and secondary roadways, and these timing durations may vary by time of day. It is 

acceptable to assume that all fixed time signals within a jurisdiction operate under similar timing 

conditions. Representative signal timing will need to be developed and may be determined by 

obtaining signal timing during the field survey from a representative set of signals or may be 

obtained from discussions with local transportation engineers. It is important that the fixed 

timing signal locations and timing be identified in the analysis because it is likely that these will 

continue to operate as fixed timing signals unless augmented by traffic control personnel. The 

approach to determining the fixed signal timing should be described.

Actuated signals are more complex and allocate green time based on level of demand that 

exists at each intersection approach, and the signal timing varies depending upon approach 

volumes. One method for modeling actuated signals is to allocate green time based on the 

level of demand flow between the primary and secondary cross streets to simulate saturated 
20

conditions in each direction. This method can effectively address the actuated signal 

conditions. The approach to modeling actuated signal control must be documented within the 

report.

Manned traffic controlled intersections are those locations where traffic control personnel will be 

stationed during the evacuation to support traffic movement through the intersection. One 

method for modeling manned traffic controlled intersections is to treat these as actuated signals 

and adjust the signal timing to reflect more efficient operations. It may be assumed that traffic 

control personnel will attempt to move traffic through the intersection in a way similar to that of 

an actuated signal by reducing the lost time of through traffic and turning traffic.

In general, it may be assumed that manned traffic controlled intersections operate most 

efficiently. Actuated signals would be less efficient, fixed timing signals still less efficient, and 

non-signalized intersections would be the least efficient intersections. For simulation models

that adjust the signal cycle length within a single model run, a discussion of the process to 

adjust the cycle timing should be provided. It should be clear if signal timing is adjusted within 

the model for all intersections, for actuated signals, and for intersections manned by response 

personnel to direct traffic. Characteristics of the 10 highest volume intersections within the EPZ 

should be provided, including the location, signal cycle length, green time allocation, and turning 

lane queue capacity as used in the modeling.

3.4 Adverse Weather

The adverse weather condition is intended to represent weather conditions that are probable 

within the region. It is not necessary to evaluate those adverse weather conditions that may 

occur at frequencies of 100 years or longer. The reduction factors in Table 3-1 may be used for 

the adverse weather conditions. Impacts of adverse weather can vary based on the region and 

familiarity of the drivers to the weather condition, therefore, the factors provided in Table 3-1 are 

guidance and may be adjusted based on local conditions.

Table 3-1 Weather Capacity Factors

Weather Condition Roadway Capacity Speed

Normal 100% 100%

Adverse – Heavy Rain 90% 85%

Adverse – Heavy Snow/Ice 85% 65%

Adverse – Fog 75% 85%

The values in Table 3-1 for heavy rain and snow are derived from Chapter 22 of the HCM, 

Exhibit 22-7 (TRB, 2000) and the Federal Highway Administration study, “Identifying and 

Assessing Key Weather-Related Parameters and Their Impacts on Traffic Operations Using 

Simulation” (FHWA, 2004b). Little research has been conducted on ice or fog, but ice is 

frequently observed to have a similar effect as heavy snow.

The effect of adverse weather on mobilization should also be considered. For heavy snow 

scenarios, snow removal equipment may be necessary to clear access roads for the 

evacuation. The time for snow removal crews to mobilize and clear snow should be considered 

in the trip generation time developed for the site. Frequently municipal snow removal 

equipment is operating during snowfall to maintain access; thus, this may not have much impact 

on time elements. Time may need to be considered in the trip generation time for the clearance 

of snow from driveways by residents.
21

4.0 DEVELOPMENT OF EVACUATION TIMES

The objective of this section is to identify how evacuation preparation activities are developed 

and quantified and how to present the ETE modeling methods and data to facilitate review. 

Preparation activities, including the time to receive the notification and time to prepare to 

evacuate, are developed as elements of the trip generation time, sometimes referred to as 

mobilization time. The trip generation time is then integrated into the calculation of the ETE. 

For EPZs where the population density is low and there is minor congestion, the travel time 

element of the evacuation may be conducted quickly, and the total ETE may be very close to 

the trip generation time. For higher population density sites where there is congestion and 

travel is slowed during the evacuation, the travel time may be influenced more by the ratio of 

demand to capacity (v/c ratio) than by the trip generation time.

The ETE supports protective action recommendations and decisions and reflects the response 

of the public to evacuation orders. It is therefore important to understand that ETEs that 

overestimate or underestimate the evacuation time are not helpful in making the best protective 

action decision. This approach differs from traditional traffic analyses which are often 

conservative. During evacuations, there is a small percentage of the population that takes 

longer to evacuate, often referred to as the evacuation tail. The evacuation tail generally 

consists of the last 10 percent of evacuees. Planning is in place to evacuate 100 percent of the 

public; however, protective action recommendations and decisions should be based on the 90 

percent ETE values. For this reason, ETEs are developed for evacuation of 90 and 100 percent 

of the EPZ population. The 90 percent value informs decision makers of the estimated time to 

evacuate the vast majority of the public, and the 100 percent ETE informs decision makers on 

the likely time for the EPZ to be fully evacuated. The ETE will be used by the licensee when 

developing procedures that support making offsite protective action recommendations and 

should be used by OROs when developing offsite protective action strategies. The level of data 

required to develop an ETE study necessitates that the analyst interact directly with State and 

local agencies and facilities such as hospitals, schools, etc., to obtain current and relevant 

information needed to support the calculations.

4.1 Trip Generation Time

The trip generation time is used to develop the vehicle loading curves. The development of trip 

generation times is described in NUREG/CR-6863, “Development of Evacuation Time Estimate 

Studies for Nuclear Power Plants,” (NRC, 2005a) and includes:

• Identifying the sequence of events;

• Obtaining data for each event;

• Developing time distributions for analysis;

• Summing the distributions; and

• Calculating trip generation times.

Each population group has different considerations for trip generation times. Telephone 

surveys of residents within the EPZ are commonly used to develop some of the data used to 

develop the time distributions. When telephone surveys are used, the scope of the survey, area 

of the survey, number of participants, and statistical relevance should be provided. The data 

obtained from the survey should also be summarized in the ETE.
22

The trip generation time is developed from site specific information for each population group 

and varies depending on the scenario. The ETEs for the transit dependent residents, special 

facility residents, and schools are each developed separately from the general public. The 

logistics of the trip generation times for these groups can be complex and may affect the ETE 

more than the actual travel time out of the EPZ.

4.1.1 Permanent Residents and Transient Population

It is important to provide sufficient detail on the logistics of evacuation elements used to develop 

time values. For example, the permanent resident trip generation time for an event during a 

normal working day may include the following elements, each of which will have a distribution of 

times (Urbanik, 2000):

• Notification of the public – The period of time to notify the public.

• Prepare to leave work or other activity – The time between receipt of notification and 

when individuals actually leave the workplace. This element should include the time for 

residents to leave stores, restaurants, parks, or other location.

• Travel to home – The time it takes to reach home after leaving work or other activity.

• Prepare to leave for the evacuation – The time to pack and prepare the home prior to 

leaving, including such activities as removal of snow from driveways, if appropriate.

Permanent residents are assumed to evacuate from their home; however, they should not be 

assumed to be home at all times. The notification element of the trip generation time for the

transient population should consider areas where notification of persons may be difficult 

including campgrounds, hunting or fishing areas, parks, beaches, etc. As visitors to the EPZ, 

this population group will have a “prepare to leave work or other activity” element which should 

consider that individuals may return to hotels prior to evacuating. Where special events that 

draw large numbers of transients utilize transportation resources such as park and ride services, 

the logistics of such activities should be discussed. The trip generation time for the transient 

population is integrated with that of the general public to support the loading of the 

transportation network.

4.1.2 Transit Dependent Permanent Residents

Transit dependent residents include ambulatory people who are mobile and non-ambulatory 

people who need assistance. Typically, the local or county emergency management agencies 

will have emergency plans for evacuation that include the use of public buses along existing bus 

routes or along special routes for evacuation of the ambulatory transit dependent population. 

Existing plans and bus routes should be used in the ETE analysis when available. If new plans 

are developed with the ETE, the new plans should be agreed upon by the responsible 

authorities. A description of the means of evacuating these residents should be provided and 

should include the number of buses needed to support the demand estimation as previously 

determined. The time estimated for transit dependent residents to prepare and then travel to 

bus pickup points should be identified as well as the expected method of travel to the pickup 

points. Development of the ETE should include confirmation of the type and number of 

resources available and whether resources are available locally or need to be mobilized from 

outside the EPZ. The intent is not to physically verify each vehicle but to confirm that 

commitments are established to provide all of the resources needed. When buses are used, the 

time needed for residents to prepare and get to the bus stop should be included in the trip 

generation time.
23

The trip generation time should address the availability of buses. Municipal buses are generally 

used throughout the day and may not be immediately available to support an evacuation. 

Buses may need to complete their normal routes prior to being available. Logistical details 

should be evaluated and may include time to obtain buses, brief drivers, and initiate the bus 

route. The number of bus stops and the time needed to load passengers should be provided to 

support the bases of the time estimates. A map of bus routes should be provided.

The local or county emergency management agencies may also have emergency plans for 

evacuation of the non-ambulatory residents. The evacuation of these residents will require the 

use of ambulances, wheelchair vans, or other specialized vehicles. The location of these 

resources should be identified. The trip generation time should include time to mobilize 

ambulances or special vehicles, time to drive to the homes of the non-ambulatory residents, 

loading time, and time to drive out of the EPZ.

In calculating the travel time to exit the EPZ, vehicle speeds should be consistent with traffic 

speeds for the actual route used and should not be based on the average roadway speed for 

the full EPZ. When there are not enough vehicles to conduct the evacuation in a single trip, the 

following additional information should be provided:

• Location of the destination point;

• Travel time to the congregate care center or other special facility, as appropriate;

• Time to unload;

• Travel time back through the EPZ to pick up additional residents; and

• Travel time to exit the EPZ.

The above steps are repeated as necessary until all of the transit dependent residents have 

been evacuated. In the multiple-trip scenario, the travel speeds may be limited by evacuation 

traffic and traffic control on portions of the route for both inbound and outbound vehicles.

4.1.3 Special Facilities

The evacuation logistics for special facilities requires developing information to establish the 

time for mobilization of resources, loading of special facility residents, and travel out of the EPZ. 

Specially trained staff, such as medical support or security support for prisons, jails, and other 

correctional facilities, may need to be contacted and mobilized along with vehicles and drivers. 

The logistics for mobilizing specially trained staff should be discussed when appropriate. 

Information on evacuation logistics should be provided for the following:

• Time needed to contact the drivers;

• Time for drivers to arrive at the transit depot;

• Time for briefing, receipt of radios, fueling of buses, etc., as applicable; and

• Inbound travel time from the depot to the special facilities.

The inbound speeds of vehicles to support the evacuation should consider that traffic control 

may be in place which may slow inbound traffic. The time for loading of special facility residents 

should be established and may be dependent on the size of the facility. Information should be 

provided for the following:
24

• Time for loading of residents. For small population facilities, this activity may be 

performed relatively quickly. For larger population facilities where a large number of 

vehicles are planned to be loaded, the details of vehicle queuing and loading should be 

discussed. The analysis should consider the time to cycle vehicles to the facility 

entrance to load residents.

• For special facilities, the number of wheelchair and bedbound individuals should be 

identified, and the logistics of evacuating these residents should be discussed.

The outbound speeds should be developed with consideration of the prevailing traffic conditions 

at the time and should be obtained from the model output for the specific routes, when 

available. Information on evacuation of special facilities should be provided in a comprehensive 

format similar to Table 4-1.

Table 4-1 Special Facilities ETE

Facility Population Number/Type 

of Vehicles

Mobilization 

Time

Vehicle 

Queue 

Length

Loading 

Time

Distance 

to EPZ 

Boundary

Outbound 

Travel

Speed

Travel 

Time to 

EPZ 

Boundary

ETE

When return trips are needed, the destination of the buses is necessary to develop the ETE. 

For special facilities, this may be a hospital, prison, etc., outside of the EPZ rather than a 

congregate care center. The ETE should identify whether a reception center is used in the 

evacuation and if special facility residents are expected to pass through the reception center 

prior to being transported to their final destination. The time elements for subsequent trips 

should include the following:

• Time to travel to the unloading point;

• Time to unload;

• Time to travel back to the facility;

• Time to load the second group; and

• Time to travel out of the EPZ.

4.1.4 Schools

The evacuation logistics for schools also requires developing information to establish the time 

for mobilization of resources, loading of students, and travel out of the EPZ. Information on 

evacuation logistics should be provided for the following:

• Time needed to contact the drivers;

• Time for drivers to arrive at the transit depot;

• Time for briefing, receipt of radios, fueling of buses, etc., as applicable; and

• Inbound travel time from the depot to the schools.

The inbound speeds of buses to support the evacuation should consider that traffic control may 

be in place which may slow inbound traffic. The time for loading students should be established 

and may be dependent on the population of the schools. Information should be provided for the 

following:

• Time for loading students. For small population schools (i.e., a few hundred students), 

this activity may be performed relatively quickly. For larger population schools where a 
25

large number of buses are planned to be loaded, the details of bus queuing and loading 

should be discussed. Typically, this would include schools requiring more than 20 buses 

to arrive and load students at the same time.

The outbound speeds should be developed with consideration of the prevailing traffic conditions 

at the time and should be obtained from the model output for the specific routes, when 

available. Information on evacuation of schools should be provided in a comprehensive format 

similar to Table 4-2.

Table 4-2 Schools ETE

School 

Name Population Number of Buses

Mobilization 

Time

Bus

Queue 

Length

Loading 

Time

Distance 

to EPZ 

Boundary

Outbound 

Travel

Speed

Travel 

Time to 

EPZ 

Boundary

ETE

When return trips are needed, the destination of the buses is necessary to develop the ETE. 

The ETE should identify whether a reception center is used in the evacuation and if students are 

expected to pass through the reception center prior to being evacuated to their final destination. 

The time elements for subsequent trips should include the following:

• Time to travel to the unloading point;

• Time to unload;

• Time to travel back to the schools;

• Time to load the second group; and

• Time to travel out of the EPZ.

4.2 ETE Modeling

This section discusses the inputs and outputs of the traffic simulation models. Traffic simulation 

modeling is usually conducted to develop the ETE for the general public population group, and 

analysts that perform this modeling should understand traffic simulation applications. There are 

a variety of models and commercial services available to support a simulation analysis. The 

DOT sponsored “Evacuation Management Operations (EMO) Modeling Assessment: 

Transportation Modeling Inventory” is also available to support selection of an appropriate 

model for use in evacuation analysis (DOT, 2007). The FHWA toolbox for use in modeling 

roadway networks is also helpful in the development of traffic simulation (FHWA, 2004a). Note 

that the FHWA modeling toolbox is intended to support transportation planning and is not 

specific to evacuations; therefore, appropriate adjustments are necessary.

The DOT and FHWA sources discuss microscopic, mesoscopic, and macroscopic models, any 

of which may be appropriate for use. As the number of commercially available models and 

professional services to develop ETEs increases, it is important that only models that have been 

demonstrated for use in the development of ETEs or in assessing transportation networks be 

used in the development of ETEs. General information about the model should be provided to 

include prior use in the development of ETE studies for NPPs or other applicable commercial or 

government applications. It is also important for the analyst to understand the analysis tools 

and the sensitivities of input parameters. If an ETE is developed without the aid of a traffic 

simulation model, such as for a sparsely populated site, the analytical approach should be 

consistent with this section, and the study should include the detailed information requested, as 

applicable.
26

The use of traffic simulation modeling in the development of ETEs provides the ability to assess 

evacuation of EPZs with great detail. Because models produce results using embedded 

algorithms and input data, it has become more difficult to review the analysis. In “The 

Sensitivity of Evacuation Time Estimates to Changes in Input Parameters for the I-DYNEV 

Computer Code,” (NRC, 1988b), several parameters were identified as sensitive, meaning that 

when these parameters were adjusted the resulting ETE was noticeably affected. The study 

underscores the importance of the model input values. Some sensitive parameters identified 

(NRC, 1988b) include:

• Number of vehicles – Evacuation times increased approximately linear to the increase in 

population;

• Roadway capacity – Changes in roadway capacity affect the evacuation time in a linear 

manner; and

• Trip Generation Time – As the trip generation time, which is used to develop vehicle 

loading curves, approaches evacuation time, the evacuation time increases 

proportionately to the trip generation time.

Traffic simulation modeling is an improved approach over simplistic comparisons of demand to 

capacity for the complex analyses required for an ETE, and it is necessary to develop these 

models in a transparent manner. For this reason, measures of effectiveness (MOEs) will be 

established for use in evaluating the traffic simulation activities. Key performance

characteristics derived from the model output will provide these MOEs.

4.2.1 Traffic Simulation Model Input

Traffic simulation model assumptions and input parameters should be provided to support 

analysis. A representative set of model inputs should be provided for at least the following:

• Roadway capacity values, if necessary for the model;

• Total vehicles entering the network;

• Vehicle occupancy (persons per vehicle);

• Time based vehicle loading curves for origin nodes;

• Data input at origin nodes;

• Directional preference; and

• Destination nodes and capacities.

Not all loading data needs to be provided for review, but full data sets for at least five nodes 

should be provided. It is not uncommon for different models to have different definitions for 

similar variables (TRB, 2000); therefore, a glossary should be provided to support the review. A 

list that includes nodes, links, and loading input information should be provided as shown in 

Table A-1 of Appendix A.

4.2.2 Traffic Simulation Model Output

A discussion regarding whether the traffic simulation model used in the analysis must be in 

equilibrium prior to calculating the ETE should be provided. Equilibrium is established by 

running a model until the number of vehicles entering the roadway network is equal to the 

number of vehicles exiting the network. Model output provides the MOEs for the ETE study. 

Examples of MOEs include traffic-based performance measures such as average travel times, 
27

total number of vehicles exiting the system, and queue lengths at various times during the 

evacuation. At a minimum, the following output should be provided in a table for the evacuation 

of the whole EPZ.

• Total volume and percent of vehicles by hour at each EPZ exit node;

• Network wide average travel time;

• The longest queue length for the 10 intersections with the highest traffic volume;

• Total vehicles exiting the network;

• A plot that provides both the mobilization curve and evacuation curve identifying the 

cumulative percentage of evacuees who have mobilized and exited the EPZ; and

• Average speed for each major evacuation route that exits the EPZ.

Additional or alternative MOEs may be provided for sites where other performance measures 

might provide a better view of the traffic conditions and resulting ETEs.

To describe the operational conditions of the roadway network, the Level of Service (LOS), as 

defined in the HCM, provides a quality measure. The LOS represents the range of traffic 

operational characteristics and is designated as “A” for free flow operating conditions through 

“F” for forced flow or congested operating conditions. The LOS is used to describe the levels of 

congestion at selected time intervals during an evacuation. Color coded graphics should be 

provided identifying areas where congestion exists (e.g., LOS “E” and LOS “F” conditions). 

These graphics should be provided for various times for a full EPZ evacuation scenario.

4.3 Evacuation Time Estimates for the General Public

The ETE should include the time to evacuate 90 percent and 100 percent of the total permanent 

resident and transient population of the affected ERPAs and should include an analysis of the 

staged evacuation protective action. The ETEs for the transit dependent population, special 

facilities and schools are developed separately, and only the time to evacuate 100 percent of 

these population groups is needed.

When developing the 100 percent ETE value for the general public, it should include all 

members of the general public within the affected ERPAs. Any reductions in trip generation 

times and truncating of trip generation time values must be explained in detail. Truncation is the 

reduction in trip generation time values to limit the effect of a very small number of residents 

who take an excessive amount of time to prepare to evacuate. Existing telephone surveys 

eliciting data on the expected time needed to prepare to evacuate show that a small number of 

residents may take considerably longer to evacuate. This extra time can extend an ETE 

disproportionately with respect to the remaining population. When such data is received from 

public surveys, adjustment or truncation of times is acceptable if a valid basis is provided.

Traffic simulation model results need to be presented such that they are readily understood and 

interpreted by decision makers and reviewers of the study. The 90 and 100 percent ETEs 

should be developed for the following:

• 0-2 mile zone;

• 2-5 mile zone for a staged evacuation;

• 0-5 mile zone;

• Affected ERPAs necessary to support site specific PAR logic (i.e., keyhole based on 

wind direction); and
28

• Complete EPZ.

Separate ETE tables should be provided for the 90 percent and for the 100 percent evacuation 

times for the full set of scenarios evaluated. These tables should follow the format presented in 

Table 4-3.

Separate ETEs should be provided for the transit dependent population, special facilities, and 

schools for just the 100 percent evacuation. The Special Event ETE is provided and is based 

on the demand estimation developed earlier. The roadway impact scenario is not included in 

Table 4-3 because the only purpose of this scenario is to support the development of traffic 

control planning.

For each scenario, an estimate of the time to complete a staged evacuation is needed. This 

analysis involves evacuating the 0-2 mile zone while the 2-5 mile zone is under a shelter in 

place order. When about 90 percent of the residents from the 0-2 mile zone have exited the 

2-mile boundary per the 90 percent ETE, the 2-5 mile zone resident population begins to 

evacuate. During the time required for the 0-2 mile zone to evacuate, the 2-5 mile zone may be 

assumed to be preparing to evacuate, which may reduce the mobilization time for this area. 

The residents in the ERPAs beyond 5 miles should be modeled to react as does the population

in the 2-5 mile zone (i.e., begin evacuation after the 90 percent ETE has expired for the 0-2 mile 

zone).

Historically, ETEs for the keyhole evacuation were developed for the 2-mile evacuation and 

5 miles downwind, but were not developed as a staged evacuation. ETEs for keyhole 

evacuations may still be developed, if desired, but should be done so in addition to the staged 

evacuation ETEs. When ETEs are developed for the keyhole inclusive of the 2-mile zone, the 

format in Table 4-4 is appropriate and 90 and 100 percent values should be provided. 

Additionally, all ETE studies should include ETEs based on site-specific PAR logic.
29

Table 4-3 ETEs for a Staged Evacuation Keyhole

100 Percent Evacuation of Affected Areas

Summer Winter

Special Midweek Event

Daytime

Weekend 

Daytime

Midweek 

Weekend 

Evening

Midweek

Daytime

Weekend

Daytime

Midweek 

Weekend

Evening

Affected 

ERPAs Scenario: (1) (2) (3) (4) (5) (6) (7) (8) (9)

Normal Adverse Normal Normal Normal Adverse Normal Normal

2-mile 

zone

5-mile 

zone

10-mile 

EPZ

Evacuate 2 to 5 miles downwind

N

NNE

NE

ENE

E

ESE

SE

SSE

S

SSW

SW

WSW

W

WNW

NW

NNW

Table 4-4 ETEs for a Keyhole Evacuation Inclusive of the 2-Mile Zone

100 Percent Evacuation of Affected Areas

Summer Winter

Special Midweek Event

Daytime

Weekend 

Daytime

Midweek 

Weekend 

Evening

Midweek

Daytime

Weekend

Daytime

Midweek 

Weekend

Evening

Affected 

ERPAs Scenario: (1) (2) (3) (4) (5) (6) (7) (8) (9)

Normal Adverse Normal Normal Normal Adverse Normal Normal

Evacuate 2-mile zone and 5 miles downwind

N

NNE

NE

ENE

E

ESE

SE

SSE

S

SSW

SW

WSW

W

WNW

NW

NNW
30

This page intentionally left blank.
31

5.0 OTHER CONSIDERATIONS

The preceding sections describe the methodology and approach to calculating the ETE. In 

addition to the calculation of an ETE, there are other considerations that need to be addressed 

in the ETE study. These considerations are described below and should be included as 

appropriate.

5.1 Development of Traffic Control Plans

Traffic simulation modeling in support of the ETE analysis can be used to assist in the 

development of traffic control plans to support an evacuation. Development of an ETE study 

provides an opportunity to model the EPZ with variations of traffic control to best affect the 

evacuation with the resources available. Where a new traffic control plan shows improvement 

in evacuation times, the new plan should be approved by responsible authorities if it is to be 

used in the ETE analysis. A discussion of adjustments or additions to the traffic control plan 

should be provided. The roadway impact scenario is used to support the development of the 

traffic control plan.

5.2 Enhancements in Evacuation Time

The ETE analysis is a tool that can be used to identify recommendations for enhancements that 

may reduce evacuation times. When evaluating potential enhancements that may reduce 

evacuation times, the evaluation may be limited to those roadways or sections of the EPZ that 

impact the ETE the greatest. This evaluation will typically include intersections and roadway 

segments where an LOS “F” occurs for some period of time. It is not expected that every 

intersection or roadway segment needs to be evaluated. The process used to select the 

intersections or roadway segments for evaluation should be described.

Each of the following potential areas of enhancement should be addressed with a discussion 

provided on the results of each evaluation. The results should include the reduction in 

evacuation time observed in the modeling output or the expected reduction in evacuation time 

for suggested enhancements. For example:

• Increased intersection throughput - Identify opportunities to increase intersection 

throughput, such as turn restrictions or traffic control.

• Reduced trip generation time - Identify opportunities for reducing the trip generation 

time.

• Reduced evacuation tail - Identify opportunities for reducing the evacuation tail.

The results of the potential enhancements that were identified should be presented to the local 

authorities for their consideration. Documentation of the review with those authorities should be 

included in the ETE report.

5.3 State and Local Review

Interaction with State and local agencies is necessary to obtain local and regional data, 

understand the operations and resources of the emergency response capabilities, and 

understand the traffic management system. The ETE should list those agencies that have been 

contacted, and briefly, the extent of interaction with these agencies as related to the 

development of the ETE. Any issues that may affect the ETE should be discussed and 
32

resolved. This will help assure that appropriate agencies, such as those providing traffic control 

or resources to support the evacuation, are aware of the ETE strategies, issues, and 

assumptions.

5.4 Reviews and Updates

Emergency planners depend on the accuracy of the ETE analysis to support evacuation 

decisions; therefore, it should be reviewed periodically to identify changes that may have 

occurred. Whenever population increases occur that cause ETE values to materially increase,

the ETE analysis should be updated in accordance with the requirements of Section IV of 

Appendix E to 10 CFR Part 50. Licensees shall provide an updated ETE analysis to the NRC 

within 365 days of:

1) The later of the date of the availability of the 2010 decennial census data or the 

effective date of the emergency preparedness final rule;

2) The availability of subsequent decennial census data; and

3) When a population increase within the EPZ causes certain ETE values to increase

by 25 percent or 30 minutes, whichever is less, as described below.

Licensees shall estimate EPZ permanent resident population changes at least annually during 

the years between decennial censuses using U. S. Census Bureau data. These estimates shall 

occur no more than 365 days apart. State/local government population data may also be used, 

if available. Licensees shall maintain these estimates available for NRC inspection during the 

period between censuses and shall submit these estimates to the NRC with any updated ETEs.

If at any time during the decennial period, the population increases so that the ETE for the 

2-mile zone or 5-mile zone, including all affected ERPAs, or for the entire EPZ, increases by 

25 percent or 30 minutes, whichever is less, for the scenario with the longest ETE, the ETE

analysis must be updated to reflect the impact of that population increase. Licensees should 

perform a population sensitivity study, during development of the ETE, to determine the 

population value that will cause ETE values to increase by 25 percent or 30 minutes, whichever 

is less. The sensitivity study should be performed and included with the baseline ETE. For 

example, assume the sensitivity study shows that an increase of 25 percent or 30 minutes 

occurs with a permanent resident population increase of 10,000 people. The licensee would 

review the EPZ population annually and when an increase of 10,000 people occurs, an updated 

ETE analysis will be developed and submitted within 365 days. Licensees can assume that the 

roadway infrastructure and capacity values, and transient populations are unchanged from the 

baseline ETE analysis when performing the population sensitivity study.

The evaluation criteria in Appendix B will be used during the reviews of the updated ETE 

analyses to confirm their completeness. During the years between decennial censuses, NRC 

Headquarters staff will inform FEMA Headquarters on a quarterly basis of any updated ETE 

analyses received. NRC Headquarters staff will also notify FEMA Headquarters and the 

appropriate NRC regional office when these updated ETE analyses have been reviewed. 

Since the NRC will review the updated ETE analyses for completeness, licensees are required 

under Sections IV.4 and IV.6 of Appendix E to submit updated ETE analyses to the NRC at 

least 180 days before they use them to form protective action recommendations or provide them 

to offsite authorities for use in developing offsite protective action strategies.
33

5.4.1 Extreme Conditions

In the unlikely event that the conditions of an EPZ are changed significantly due to natural 

phenomena hazards or for other reasons, such as a bridge collapse on a primary roadway, an 

update to the ETE analysis should be developed. The updated ETE is necessary to account for 

the current state of the EPZ when these changed conditions are expected to persist for at least 

a few months, as it may take that long to develop an update. Planned activities, such as 

construction or infrastructure projects, are expected to have compensatory measures in place 

such that the activities do not affect the ETE. Therefore, the extreme condition updates are 

intended to apply only for unplanned changes within an EPZ and are not intended to apply to 

planned activities. An update prepared to satisfy the extreme conditions criteria does not need 

to include a full revision to the ETE analysis, but rather should address only those extreme 

condition elements that affect the ETE. The update should be shared with appropriate OROs.

5.5 Reception Centers and Congregate Care Centers

Evacuation planning includes the use of congregate care centers, which are established as 

shelter facilities for evacuees. For many EPZs, reception centers are used along with 

congregate care centers in the evacuation process. Reception centers are those facilities 

where evacuees are registered, and if necessary, screened for potential contamination prior to 

going to a congregate care center. Evacuees do not stay at reception centers. The location of 

reception centers and congregate care centers may be an important factor in the ETE analysis. 

Schoolchildren, transit dependent residents, and people with disabilities and those with access 

and functional needs may be bused to reception centers for screening, and then bused to 

congregate care centers or other special facilities that provide appropriate care. These activities 

occur outside the EPZ and are not factored into the time estimates except in those cases where 

buses must return to the EPZ to support subsequent evacuation trips.

For EPZs where return trips are needed for buses or other vehicles, the location of these 

facilities and logistics of offloading passengers prior to returning to the EPZ will directly affect 

the evacuation time. These logistics include such actions as unloading vehicles, screening the 

passengers, reloading the vehicles, and travel to the congregate care center, as appropriate. A

map identifying the location of congregate care centers and reception centers, if used, should 

be provided. Discussion should be provided on the assumptions for the time necessary for 

buses to return to the EPZ and start the next wave of evacuation. If it is assumed that 

passengers are left at the reception center and taken by separate buses to the congregate care 

center, this should be clearly stated and consistent with the local emergency planning.

5.6 New Reactors

The construction of new reactors may occur at sites with existing reactors where emergency 

response programs are established, or may occur on green field sites where such programs are 

not in place. For sites at which there are existing emergency response programs, the ETE 

analysis developed for the new reactor should be prepared to address any impacts that the new 

reactor may have on the evacuation time. Considerations include addressing the number of 

workers and suppliers at the site during the peak construction period. The addition of 

employees and support staff that may reside within the EPZ is also a consideration as well as 

potential growth throughout the EPZ during the construction phase. Generally, the support 

provided by local emergency response organizations has been established and development of 

an ETE should include confirming that any additional resources needed would be available. For 

green field sites, emergency response programs are not in place, evacuations plans have not 
34

been approved and tested by local authorities, and locations of congregate care centers have 

likely not been established. These conditions necessitate that the development of the ETE 

analysis be coordinated with the development of the emergency response program being 

prepared during the licensing phase. Assumptions used in the ETE must be consistent with the 

assumptions and proposed resources and infrastructure identified within the emergency 

response plan to provide an accurate time estimate. ETEs for new reactor applications should 

be developed based on the most recent decennial census data projected to the year the license 

application will be submitted. An ETE update for the new reactor is not needed until 365 days 

before the licensee’s scheduled fuel load if the population increase criteria have been met. 

After beginning operations, the licensee must comply with NRC regulations concerning the 

frequency of ETE reviews and updates as for any other operating licensee.

5.7 Early Site Permits

The ETE developed in support of an early site permit (ESP) should consider all of the elements 

identified in this guidance document. Data and information should be provided to support 

current conditions and projected conditions through construction of the NPP. Assumptions may 

be used to augment specific elements that are not yet defined, such as the location of 

congregate care centers. Any significant impediments that affect evacuation times should be 

identified. Data and information should be updated, as appropriate, to ensure up-to-date 

information is used to develop the ETE, when a combined license (COL) application, which 

incorporates an ESP, is submitted. ETEs for ESPs should be developed based on the most 

recent decennial census data projected to the year the ESP will be submitted. An ETE update 

for the new reactor identified within the ESP is not needed unless a COL is issued for that 

reactor. The licensee must then perform updates as directed in Section 5.6 for new reactors.
35

6.0 GLOSSARY

Demand Estimation – The total number of evacuees by population group including vehicles.

Emergency Response Planning Areas (ERPAs) – Defined areas that constitute the EPZ and 

for which emergency response plans have been developed. These areas are typically defined 

by geographic or political boundaries to support emergency response planning and may also be

referred to as subareas, protective action areas, or other local terminology.

Evacuation Tail – A small portion of the population that takes a longer time to evacuate than 

the rest of the general public and is the last to leave the evacuation area. The tail generally 

conforms to about the last 10 percent of the population.

Keyhole Evacuation – An evacuation of the 2-mile radius around an NPP and the downwind 

sectors forming a keyhole configuration.

Link – A segment of roadway between two nodes.

Loading Curve – The rate at which vehicles are entered onto the roadway network.

Measure of Effectiveness (MOE) – Statistics used to describe performance. As applied in this 

document, these include output data that provide key performance characteristics of the 

roadway network and the evacuation time.

Node – An identification designator used to connect links in a roadway network model or to 

apply input data onto the network. Nodes are at intersections, ramps, etc., and contain 

characteristics such as traffic control and may be used as input points to assign loading of 

vehicles.

Permanent Resident – All people having a residence in the area.

Roadway Capacity – The maximum rate at which vehicles can be reasonably expected to 

traverse a point or uniform section of roadway during a given time period under prevailing 

conditions. (TRB, 2000)

Shadow Evacuation – Evacuation of persons from areas outside any officially declared 

evacuation zone.

Special Event – An activity where large transient populations are present for a limited period of 

time.

Special Facilities – Facilities where residents are confined or dependent upon facility 

personnel for transportation, including nursing homes, assisted living centers, hospitals, jails, 

prisons, and other similar facilities.

Staged Evacuation – A protective action where one area is ordered to evacuate while adjacent 

areas are ordered to shelter in place until ordered to evacuate.

Transient Population – Tourists, shoppers, employees, etc., who do not reside within the EPZ, 

and other people temporarily visiting the EPZ.
36

Trip Generation Time – Time elapsed for each population group from when the evacuation 

order was disseminated until the time when the evacuation trip actually begins (e.g., when the 

car leaves the driveway).
37

7.0 REFERENCES

Department of Transportation (DOT). “Evacuation Management Operations (EMO) 

Modeling Assessment: Transportation Modeling Inventory.” Research and Innovative 

Technology Administration (RITA) Intelligent Transportation System Joint Program Office, 

October 2007. (DOT, 2007).

Dheenadayalu, Y., B. Wolshon, and C. Wilmot. “Analysis of Link Capacity Estimation 

Methods for Urban Planning Models.” ASCE Journal of Transportation Engineering, 

American Society of Civil Engineers, Vol. 130, No. 5, pp. 568–575, September/October 

2004. (ASCE, 2004).

Federal Emergency Management Agency (FEMA). FEMA Nuclear Facilities and Population 

Density Within 10 Miles Map, June 2005. (FEMA, 2005).

Federal Highway Administration (FHWA). “Traffic Analysis Toolbox Volume II: Decision 

Support Methodology for Selecting Traffic Analysis Tools.” U.S. Department of 

Transportation. Publication No. FHWA-HRT-04-039, July 2004. (FHWA, 2004a).

Federal Highway Administration (FHWA). “Identifying and Assessing Key WeatherRelated Parameters and Their Impacts on Traffic Operations Using Simulation.” U.S. 

Department of Transportation. Publication No. FHWA-HRT-04-131. September 2004. 

(FHWA, 2004b).

Institute for Environmental Studies (IES), University of Toronto. “The Mississauga 

Evacuation Final Report,” June 1981. (IES, 1981).

Urbanik, Thomas. “Evacuation Time Estimates for Nuclear Power Plants.” Journal of 

Hazardous Materials, Vol. 75, pp. 165-180, 2000. (Urbanik, 2000).

Nuclear Regulatory Commission (NRC). NUREG/CR-6981, SAND2008-1776P, 

“Assessment of Emergency Response Planning and Implementation for Large Scale 

Evacuations,” October 2008. (NRC, 2008a).

Nuclear Regulatory Commission (NRC). NUREG/CR-6953, Vol. II, SAND2007-5448P,

“Review of NUREG-0654, Supplement 3, ‘Criteria for Protective Action Recommendations 

for Severe Accidents – Focus Groups and Telephone Survey,’” October 2008. (NRC, 

2008b).

Nuclear Regulatory Commission (NRC). NUREG/CR-6953, Vol. I, SAND2007-5448P,

“Review of NUREG-0654, Supplement 3, ‘Criteria for Protective Action Recommendations 

for Severe Accidents,’” December 2007. (NRC, 2007).

Nuclear Regulatory Commission (NRC). NUREG/CR-6863, SAND2004-5900,

“Development of Evacuation Time Estimate Studies for Nuclear Power Plants,” January 

2005. (NRC, 2005a).

Nuclear Regulatory Commission (NRC). NUREG/CR-6864, SAND2004-5901, “Identification 

and Analysis of Factors Affecting Emergency Evacuations,” January 2005. (NRC, 2005b).
38

Nuclear Regulatory Commission (NRC). NUREG-0654/FEMA-REP-1, Rev. 1, Supplement 

2, “Criteria for Preparation and Evaluation of Radiological Emergency Response Plans and 

Preparedness in Support of Nuclear Power Plants – Criteria for Emergency Planning in an 

Early Site Permit Application,” Draft Report for Comment, 1996. (NRC, 1996).

Nuclear Regulatory Commission (NRC). NUREG/CR-4831, PNNL-7776, “State of the Art in 

Evacuation Time Estimate Studies for Nuclear Power Plants,” 1992. (NRC, 1992).

Nuclear Regulatory Commission (NRC). NUREG/CR-4873, PNL-6171, “Benchmark Study 

of the I-DYNEV Evacuation Time Estimate Computer Code,” 1988. (NRC, 1988a).

Nuclear Regulatory Commission (NRC). NUREG/CR-4874, PNL-6172, “The Sensitivity of 

Evacuation Time Estimates to Changes in Input Parameters for the I-DYNEV Computer 

Code,” 1988. (NRC, 1988b).

Nuclear Regulatory Commission (NRC). NUREG-0654/FEMA-REP-1, Rev. 1. “Criteria for 

Preparation and Evaluation of Radiological Emergency Response Plans and Preparedness 

in Support of Nuclear Power Plants,” November 1980. (NRC, 1980).

Transportation Research Board (TRB). “Highway Capacity Manual.” National Research 

Council, Washington, DC, 2000. (TRB, 2000).
APPENDIX A

ROADWAY NETWORK CHARACTERISTICS
A-1

Roadway Network Characteristics

The development of an ETE requires detailed data on the characteristics of the existing 

roadways within the EPZ. Frequently hundreds of links and nodes are developed for an 

analysis. This information is used in the calculations to support roadway capacity calculations 

that influence the ETE. A listing of roadway characteristics should be provided and should 

include the following information:

Link # The unique identifier for each roadway segment between two 

nodes.

U-Node Upstream node number for associated link.

D-Node Downstream node number for associated link.

Length Length of the roadway segment.

Lane Width Width of lane for the link.

Number of Lanes Number of lanes in the direction of travel.

Roadway Type As defined in the ETE study such as Interstate, major arterial, 

minor arterial, etc.

Saturation Flow Rate The equivalent hourly rate at which vehicles can traverse an 

intersection approach under prevailing conditions, assuming 

that the green signal is available at all times and no lost times 

are experienced in vehicles per hour of green per lane.

FFS Free flow speed over the link.
A-2

Figure A-1 Roadway Network Nodes and Segments

A map of the roadway network should be provided similar to Figure A-1 and should include 

legible values for nodes and links.

Table A-1 should be included to provide detailed information on each roadway segment 

considered in the ETE calculations. The links and nodes in Table A-1 should correspond to the 

roadway network and should represent the values used in the analysis.

Table A-1 Roadway Characteristics

Roadway Characteristics

Link

# U-Node D-Node Length Lane 

Width

Number of 

Lanes

Roadway 

Type

Saturation 

Flow Rate FFS
A-3

This page intentionally left blank.
APPENDIX B

EVACUATION TIME ESTIMATE

EVALUATION CRITERIA
Table B-1 ETE Review Criteria Checklist

Criterion Addressed in 

ETE Analysis Comments

(Yes/No)

1.0 Introduction

a. The emergency planning zone (EPZ) and surrounding area 

should be described.

b. A map should be included that identifies primary features of 

the site, including major roadways, significant topographical 

features, boundaries of counties, and population centers 

within the EPZ.

c. A comparison of the current and previous ETE should be 

provided and includes similar information as identified in 

Table 1-1, “ETE Comparison,” of NUREG/CR-7002.

1.1 Approach

a. A discussion of the approach and level of detail obtained 

during the field survey of the roadway network should be 

provided.

b. Sources of demographic data for schools, special facilities, 

large employers, and special events should be identified. 

c. Discussion should be presented on use of traffic control 

plans in the analysis.

d. Traffic simulation models used for the analyses should be 

identified by name and version.

e. Methods used to address data uncertainties should be

described.

1.2 Assumptions

a. The planning basis for the ETE includes the assumption that 

the evacuation is ordered promptly and no early protective 

actions have been implemented.

b. Assumptions consistent with Table 1-2, “General 

Assumptions,” of NUREG/CR-7002 should be provided and 

include the basis to support their use.

1.3 Scenario Development

a. The ten scenarios in Table 1-3, Evacuation Scenarios, 

should be developed for the ETE analysis, or a reason 

should be provided for use of other scenarios.

B-1
Criterion Addressed in 

ETE Analysis

Comments

(Yes/No)

1.3.1 Staged Evacuation

a. A discussion should be provided on the approach used in 

development of a staged evacuation.

1.4 Evacuation Planning Areas

a. A map of the EPZ with emergency response planning areas (ERPAs) should be included.

b. A table should be provided identifying the ERPAs 

considered for each ETE calculation by downwind direction 

in each sector.

c.A table similar to Table 1-4, “Evacuation Areas for a Staged 

Evacuation Keyhole,” of NUREG/CR-7002 should be 

provided and includes the complete evacuation of the 2, 5, 

and 10 mile areas and for the 2 mile area/5 mile keyhole 

evacuations.

2.0 Demand Estimation

a. Demand estimation should be developed for the four 

population groups, including permanent residents of the 

EPZ, transients, special facilities, and schools.

2.1 Permanent Residents and Transient Population

a. The US Census should be the source of the population 

values, or another credible source should be provided.

b. Population values should be adjusted as necessary for 

growth to reflect population estimates to the year of the ETE.

c. A sector diagram should be included, similar to Figure 2-1, 

“Population by Sector,” of NUREG/CR-7002, showing the 

population distribution for permanent residents.

2.1.1 Permanent Residents with Vehicles

a. The persons per vehicle value should be between 1 and 2 or 

justification should be provided for other values.

b. Major employers should be listed.

2.1.2 Transient Population

a. A list of facilities which attract transient populations should 

be included, and peak and average attendance for these 

facilities should be listed. The source of information used to 

develop attendance values should be provided.

b. The average population during the season should be used,

B-2
Criterion Addressed in 

ETE Analysis

Comments

(Yes/No)

itemized and totaled for each scenario.

c. The percent of permanent residents assumed to be at 

facilities should be estimated.

d. The number of people per vehicle should be provided. 

Numbers may vary by scenario, and if so, discussion on why 

values vary should be provided.

e. A sector diagram should be included, similar to Figure 2-1 of 

NUREG/CR-7002, showing the population distribution for 

the transient population.

2.2 Transit Dependent Permanent Residents

a. The methodology used to determine the number of transit 

dependent residents should be discussed.

b. Transportation resources needed to evacuate this group 

should be quantified.

c. The county/local evacuation plans for transit dependent 

residents should be used in the analysis.

d. The methodology used to determine the number of people 

with disabilities and those with access and functional needs

who may need assistance and do not reside in special 

facilities should be provided. Data from local/county 

registration programs should be used in the estimate, but 

should not be the only set of data.

e. Capacities should be provided for all types of transportation 

resources. Bus seating capacity of 50% should be used or 

justification should be provided for higher values.

f. An estimate of this population should be provided and 

information should be provided that the existing registration 

programs were used in developing the estimate.

g. A summary table of the total number of buses, ambulances, 

or other transport needed to support evacuation should be

provided and the quantification of resources should be

detailed enough to assure double counting has not occurred.

2.3 Special Facility Residents

a. A list of special facilities, including the type of facility, 

location, and average population should be provided. 

Special facility staff should be included in the total special 

B-3
Criterion Addressed in 

ETE Analysis

Comments

(Yes/No)

facility population.

b. A discussion should be provided on how special facility data 

was obtained.

c. The number of wheelchair and bed-bound individuals should 

be provided.

d. An estimate of the number and capacity of vehicles needed 

to support the evacuation of the facility should be provided.

e. The logistics for mobilizing specially trained staff (e.g., 

medical support or security support for prisons, jails, and 

other correctional facilities) should be discussed when 

appropriate.

2.4 Schools

a. A list of schools including name, location, student 

population, and transportation resources required to support 

the evacuation, should be provided. The source of this 

information should be provided.

b. Transportation resources for elementary and middle schools 

are based on 100% of the school capacity.

c. The estimate of high school students who will use their 

personal vehicle to evacuate should be provided and a basis 

for the values used should be provided.

d. The need for return trips should be identified if necessary.

2.5.1 Special Events

a. A complete list of special events should be provided and 

includes information on the population, estimated duration, 

and season of the event.

b. The special event that encompasses the peak transient 

population should be analyzed in the ETE.

c. The percent of permanent residents attending the event 

should be estimated.

2.5.2 Shadow Evacuation

a. A shadow evacuation of 20 percent should be included for 

areas outside the evacuation area extending to 15 miles 

from the NPP.

b. Population estimates for the shadow evacuation in the 10 to 

15 mile area beyond the EPZ are provided by sector.

B-4
Criterion Addressed in 

ETE Analysis

Comments

(Yes/No)

c. The loading of the shadow evacuation onto the roadway 

network should be consistent with the trip generation time 

generated for the permanent resident population.

2.5.3 Background and Pass Through Traffic

a. The volume of background traffic and pass-through traffic 

should be based on the average daytime traffic. Values may 

be reduced for nighttime scenarios.

b. Pass-through traffic should be assumed to have stopped 

entering the EPZ about two hours after the initial notification.

2.6 Summary of Demand Estimation

a. A summary table should be provided that identifies the total 

populations and total vehicles used in the analysis for 

permanent residents, transients, transit dependent 

residents, special facilities, schools, shadow population, and 

pass-through demand used in each scenario.

3.0 Roadway Capacity

a. The method(s) used to assess roadway capacity should be

discussed.

3.1 Roadway Characteristics

a. A field survey of key routes within the EPZ has been 

conducted.

b. Information should be provided describing the extent of the 

survey, and types of information gathered and used in the 

analysis.

c. A table similar to that in Appendix A, “Roadway 

Characteristics,” of NUREG/CR-7002 should be provided.

d. Calculations for a representative roadway segment should 

be provided.

e. A legible map of the roadway system that identifies node 

numbers and segments used to develop the ETE should be

provided and should be similar to Figure 3-1, “Roadway 

Network Identifying Nodes and Segments,” of NUREG/CR-

7002.

3.2 Capacity Analysis

a. The approach used to calculate the roadway capacity for the 

transportation network should be described in detail and 

B-5
Criterion Addressed in 

ETE Analysis Comments

(Yes/No)

identifies factors that are expressly used in the modeling.

b. The capacity analysis identifies where field information 

should be used in the ETE calculation.

3.3 Intersection Control

a. A list of intersections should be provided that includes the 

total numbers of intersections modeled that are 

unsignalized, signalized, or manned by response personnel.

b. Characteristics for the 10 highest volume intersections within 

the EPZ are provided including the location, signal cycle 

length, and turn lane queue capacity.

c. Discussion should be provided on how time signal cycle is 

used in the calculations.

3.4 Adverse Weather

a. The adverse weather condition should be identified and the 

effect of adverse weather on mobilization should be 

considered.

b. The speed and capacity reduction factors identified in Table 

3-1, “Weather Capacity Factors,” of NUREG/CR-7002

should be used or a basis should be provided for other 

values.

c. The study identifies assumptions for snow removal on 

streets and driveways, when applicable.

4.0 Development of Evacuation Times

4.1 Trip Generation Time

a. The process used to develop trip generation times should be

identified.

b. When telephone surveys are used, the scope of the survey, 

area of the survey, number of participants, and statistical 

relevance should be provided.

c. Data obtained from telephone surveys should be

summarized.

d. The trip generation time for each population group should be

developed from site specific information.

4.1.1 Permanent Residents and Transient Population

a. Permanent residents are assumed to evacuate from their 

homes but are not assumed to be at home at all times. Trip 

B-6
Criterion Addressed in 

ETE Analysis

Comments

(Yes/No)

generation time includes the assumption that a percentage 

of residents will need to return home prior to evacuating.

b. Discussion should be provided on the time and method used 

to notify transients. The trip generation time discusses any 

difficulties notifying persons in hard to reach areas such as 

on lakes or in campgrounds.

c. The trip generation time accounts for transients potentially 

returning to hotels prior to evacuating.

d. Effect of public transportation resources used during special 

events where a large number of transients are expected 

should be considered.

e. The trip generation time for the transient population should 

be integrated and loaded onto the transportation network 

with the general public.

4.1.2 Transit Dependent Residents

a. If available, existing plans and bus routes are used in the 

ETE analysis. If new plans are developed with the ETE, they 

should have been agreed upon by the responsible 

authorities.

b. Discussion should be included on the means of evacuating 

ambulatory and non-ambulatory residents.

c. The number, location and availability of buses, and other 

resources needed to support the demand estimation are 

provided.

d. Logistical details, such as the time to obtain buses, brief 

drivers and initiate the bus route are provided.

e. Discussion should identify the time estimated for transit 

dependent residents to prepare and then travel to a bus 

pickup point, and describes the expected means of travel to 

the pickup point.

f. The number of bus stops and time needed to load 

passengers should be discussed.

g. A map of bus routes should be included.

h. The trip generation time for non-ambulatory persons 

includes the time to mobilize ambulances or special 

vehicles, time to drive to the home of residents, loading time, 

B-7
Criterion Addressed in 

ETE Analysis

Comments

(Yes/No)

and time to drive out of the EPZ should be provided.

i. Information should be provided to support analysis of return 

trips, if necessary.

4.1.3 Special Facilities

a. Information on evacuation logistics and mobilization times 

should be provided.

b. Discussion should be provided on the inbound and outbound 

speeds.

c. The number of wheelchair and bed-bound individuals should 

be provided, and the logistics of evacuating these residents 

should be discussed.

d. Time for loading of residents should be provided.

e. Information should be provided that indicates whether the 

evacuation can be completed in a single trip or if additional 

trips are needed.

f. If return trips are needed, the destination of vehicles should 

be provided.

g. Discussion should be provided on whether special facility 

residents are expected to pass through the reception center 

prior to being evacuated to their final destination.

h. Supporting information should be provided to quantify the 

time elements for the return trips.

4.1.4 Schools

a. Information on evacuation logistics and mobilization times 

should be provided.

b. Discussion should be provided on the inbound and outbound 

speeds.

c. Time for loading of students should be provided.

d. Information should be provided that indicates whether the 

evacuation can be completed in a single trip or if additional 

trips are needed.

e. If return trips are needed, the destination of school buses 

should be provided.

f. If used, reception centers should be identified. Discussion 

should be provided on whether students are expected to 

pass through the reception center prior to being evacuated 

B-8
Criterion Addressed in 

ETE Analysis

Comments

(Yes/No)

to their final destination.

g. Supporting information should be provided to quantify the 

time elements for the return trips.

4.2 ETE Modeling

a. General information about the model should be provided 

and demonstrates its use in ETE studies.

b. If a traffic simulation model is not used to conduct the ETE 

calculation, sufficient detail should be provided to validate 

the analytical approach used. All criteria elements should 

have been met, as appropriate.

4.2.1 Traffic Simulation Model Input

a. Traffic simulation model assumptions and a representative 

set of model inputs should be provided.

b. A glossary of terms should be provided for the key 

performance measures and parameters used in the 

analysis.

4.2.2 Traffic Simulation Model Output

a. A discussion regarding whether the traffic simulation model 

used must be in equilibration prior to calculating the ETE 

should be provided.

b. The minimum following model outputs should be provided to 

support review:

1. Total volume and percent by hour at each EPZ exit 

mode.

2. Network wide average travel time.

3. Longest Queue length for the 10 intersections with the 

highest traffic volume.

4. Total vehicles exiting the network.

5. A plot that provides both the mobilization curve and 

evacuation curve identifying the cumulative percentage 

of evacuees who have mobilized and exited the EPZ.

6. Average speed for each major evacuation route that 

exits the EPZ.

c. Color coded roadway maps should be provided for various 

times (i.e., at 2, 4, 6 hrs., etc.) during a full EPZ evacuation 

scenario, identifying areas where long queues exist 

including level of service (LOS)“E” and LOS “F” conditions, 

B-9
Criterion Addressed in 

ETE Analysis

Comments

(Yes/No)

if they occur.

4.3 Evacuation Time Estimates for the General Public

a. The ETE should include the time to evacuate 90% and 

100% of the total permanent resident and transient 

population.

b. The ETE for 100% of the general public should include all 

members of the general public. Any reductions or truncated 

data should be explained.

c. Tables should be provided for the 90 and 100 percent ETEs 

similar to Table 4-3, “ETEs for Staged Evacuation Keyhole,” 

of NUREG/CR-7002.

d. ETEs should be provided for the 100 percent evacuation of 

special facilities, transit dependent, and school populations.

5.0 Other Considerations

5.1 Development of Traffic Control Plans

a. Information that responsible authorities have approved the 

traffic control plan used in the analysis should be provided.

b. A discussion of adjustments or additions to the traffic control 

plan that affect the ETE should be provided.

5.2 Enhancements in Evacuation Time

a. The results of assessments for improvement of evacuation 

time should be provided.

b. A statement or discussion regarding presentation of 

enhancements to local authorities should be provided.

5.3 State and Local Review

a. A list of agencies contacted and the extent of interaction with 

these agencies should be discussed.

b. Information should be provided on any unresolved issues 

that may affect the ETE.

5.4 Reviews and Updates

a. A discussion of when an updated ETE analysis is required to 

be performed and submitted to the NRC.

5.5 Reception Centers and Congregate Care Center

a. A map of congregate care centers and reception centers 

should be provided.

b. If return trips are required, assumptions used to estimate 

B-10
Criterion Addressed in 

ETE Analysis Comments

(Yes/No)

return times for buses should be provided.

c. It should be clearly stated if it is assumed that passengers 

are left at the reception center and are taken by separate 

buses to the congregate care center.

Technical Reviewer Date

Supervisory Review Date

B-11