Research, Development, and Technology

Turner-Fairbank Highway Research Center

6300 Georgetown Pike

McLean, VA 22101-2296

Multiyear Plan for Bridge and Tunnel

Security Research, Development, 

and Deployment

PUBLICATION NO. FHWA-HRT-06-072 MARCH 2006
Foreword 

Protecting critical infrastructure against terrorist events is a need imposed on us by the events of 

September 11, 2001. Although the transportation community has always responded to natural 

hazards, and there are procedures in place to design for and handle these, managing for terrorist 

events presents a new challenge. Transportation is essential for mobility and commerce, and it 

plays a critical role in times of crisis. Our highways are essential for evacuation, and in the 

response and recovery effort. However, our highways are also vulnerable, and can be used by 

terrorists as a means to carry out an attack. Because the challenge is tremendous, the Federal 

Highway Administration has been proactive by reaching out to stakeholders to identify critical 

gaps and needs. This has been accomplished through several forums as presented in this report. 

The input provided by experts in the field of bridge engineering and others has been evaluated 

and a program proposed to design highway bridges and tunnels for security. 

Gary Henderson, Director 

Office of Infrastructure 

 Research and Development 

Notice 

This document is disseminated under the sponsorship of the U.S. Department of Transportation 

in the interest of information exchange. The U.S. Government assumes no liability for the use of 

the information contained in this document. This report does not constitute a standard, 

specification, or regulation. 

The U.S. Government does not endorse products or manufacturers. Trademarks or 

manufacturers’ names appear in this report only because they are considered essential to the 

objective of the document. 

Quality Assurance Statement 

The Federal Highway Administration (FHWA) provides high-quality information to serve 

Government, industry, and the public in a manner that promotes public understanding. Standards 

and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its 

information. FHWA periodically reviews quality issues and adjusts its programs and processes to 

ensure continuous quality improvement. 
Technical Report Documentation Page 

1. Report No.

FHWA-HRT-06-072 

2. Government Accession No. 3. Recipient’s Catalog No. 

5. Report Date

March 2006 

4. Title and Subtitle

Multiyear Plan for Bridge and Tunnel Security Research, 

Development, and Deployment 6. Performing Organization Code

7. Author(s)

Sheila Rimal Duwadi, P.E., and Steven B. Chase, Ph.D.

8. Performing Organization Report No.

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)

Office of Infrastructure Research and Development 

Federal Highway Administration 

6300 Georgetown Pike 

McLean, VA 22101-2296

11. Contract or Grant No.

13. Type of Report and Period Covered

Final Report 

May 2002 – June 2005

12. Sponsoring Agency Name and Address

Office of Infrastructure Research and Development 

Federal Highway Administration 

6300 Georgetown Pike 

McLean, VA 22101-2296 14. Sponsoring Agency Code

HRDI-07 

15. Supplementary Notes

16. Abstract

Transportation is identified as one of the critical infrastructures under Homeland Security Presidential Directive 

(HSPD) 7. It is essential for mobility and commerce, and plays a critical role in times of crisis. Our highways 

are essential for evacuation, and in the response and recovery effort. We have approximately 600,000 bridges 

and 300 tunnels on the highway network and many of these can be considered as being critical structures 

and/or on essential corridors. A damaged bridge or tunnel has an enormous impact on a city, a region, and 

possibly the Nation. Although the Federal Highway Administration (FHWA) has always been active in 

conducting research and development to mitigate natural hazards such as flooding and scour, earthquakes, 

wind, and wind-induced events, designing for security is a new task. Because the challenge is tremendous, 

FHWA has led multiple outreach sessions to identify needs and gaps. This input provided by experts in the 

field of bridge engineering and others has been evaluated and a program has been proposed to design 

highway bridges and tunnels for security. 

17. Key Words

Security, bridges, tunnels. 

18. Distribution Statement

No restrictions. This document is 

available to the public through the 

National Technical Information 

Service, Springfield, VA 22161.

19. Security Classif. (of this report) 

Unclassified 

20. Security Classif. (of this page)

Unclassified 

21. No. of Pages

59 

22. Price 

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized 
ii 

SI* (MODERN METRIC) CONVERSION FACTORS 

APPROXIMATE CONVERSIONS TO SI UNITS

Symbol When You Know Multiply By To Find Symbol 

LENGTH 

in inches 25.4 millimeters mm 

ft feet 0.305 meters m 

yd yards 0.914 meters m 

mi miles 1.61 kilometers km 

AREA 

in2 square inches 645.2 square millimeters mm2

ft2 square feet 0.093 square meters m2

yd2 square yard 0.836 square meters m2

ac acres 0.405 hectares ha

mi2 square miles 2.59 square kilometers km2

VOLUME 

fl oz fluid ounces 29.57 milliliters mL 

gal gallons 3.785 liters L 

ft3 cubic feet 0.028 cubic meters m3 

yd3 cubic yards 0.765 cubic meters m3 

NOTE: volumes greater than 1000 L shall be shown in m3

MASS 

oz ounces 28.35 grams g

lb pounds 0.454 kilograms kg

T short tons (2000 lb) 0.907 megagrams (or "metric ton") Mg (or "t") 

TEMPERATURE (exact degrees) o

F Fahrenheit 5 (F-32)/9 Celsius oC 

or (F-32)/1.8 

ILLUMINATION 

fc foot-candles 10.76 lux lx

fl foot-Lamberts 3.426 candela/m2 cd/m2

FORCE and PRESSURE or STRESS 

lbf poundforce 4.45 newtons N 

lbf/in2 poundforce per square inch 6.89 kilopascals kPa 

APPROXIMATE CONVERSIONS FROM SI UNITS 

Symbol When You Know Multiply By To Find Symbol 

LENGTH

mm millimeters 0.039 inches in 

m meters 3.28 feet ft 

m meters 1.09 yards yd 

km kilometers 0.621 miles mi 

AREA mm2

 square millimeters 0.0016 square inches in2 

m2 square meters 10.764 square feet ft2 

m2 square meters 1.195 square yards yd2 

ha hectares 2.47 acres ac

km2 square kilometers 0.386 square miles mi2 

VOLUME 

mL milliliters 0.034 fluid ounces fl oz 

L liters 0.264 gallons gal 

m3 cubic meters 35.314 cubic feet ft3 

m3 cubic meters 1.307 cubic yards yd3 

MASS 

g grams 0.035 ounces oz

kg kilograms 2.202 pounds lb

Mg (or "t") megagrams (or "metric ton") 1.103 short tons (2000 lb) T 

TEMPERATURE (exact degrees) o

C Celsius 1.8C+32 Fahrenheit oF 

ILLUMINATION 

lx lux 0.0929 foot-candles fc 

cd/m2 candela/m2 0.2919 foot-Lamberts fl

FORCE and PRESSURE or STRESS 

N newtons 0.225 poundforce lbf 

kPa kilopascals 0.145 poundforce per square inch lbf/in2

*SI is the symbol for th International System of Units. Approp e riate rounding should be made to comply with Section 4 of ASTM E380. 

(Revised March 2003)
iii 

TABLE OF CONTENTS 

INTRODUCTION......................................................................................................................... 1

SECTION 1: DEVELOPMENT OF A MULTIYEAR PROGRAM ....................................... 3

SECTION 2: NEEDS ASSESSMENT, BLUE RIBBON PANEL, AND THE R&D 

SECURITY WORKSHOP........................................................................................................... 5

BACKGROUND ........................................................................................................................ 5 

Needs Assessment................................................................................................................... 5 

Blue Ribbon Panel .................................................................................................................. 6 

R&D Security Workshop........................................................................................................ 6 

RESULTS ................................................................................................................................... 8 

SECTION 3: CURRENT PRACTICE AND GAPS IN KNOWLEDGE................................. 9

SECTION 4: NATIONAL PLAN FOR R&D IN SUPPORT OF CRITICAL 

INFRASTRUCTURE PROTECTION ..................................................................................... 11

SECTION 5: PROPOSED FHWA MULTIYEAR PROGRAM............................................ 13

STRATEGIC FOCUS AREAS ................................................................................................ 13 

RESEARCH PROGRAM GOALS .......................................................................................... 14 

Risk and Vulnerability Assessment ...................................................................................... 14 

System Analysis and Design................................................................................................. 14 

Improved Materials............................................................................................................... 14 

Prevention, Detection, and Surveillance............................................................................... 14 

Post-Event Assessment ......................................................................................................... 14 

Repair and Restoration.......................................................................................................... 14 

Evaluation and Training........................................................................................................ 14 

TIE-IN TO THE NATIONAL CRITICAL INFRASTRUCTURE PROTECTION R&D 

PLAN........................................................................................................................................ 14 

RESEARCH AND DEVELOPMENT RECOMMENDATIONS............................................ 15 

Risk and Vulnerability Assessment ...................................................................................... 17 

System Analysis and Design................................................................................................. 18 
iv 

Material Performance............................................................................................................ 22 

Prevention, Monitoring, Detection, and Surveillance........................................................... 24 

Post-Event Assessment ......................................................................................................... 24 

Repair and Restoration.......................................................................................................... 25 

SECTION 6: SUMMARY.......................................................................................................... 27

APPENDIX A RESEARCH NEEDS FROM NEEDS ASSESSMENT ................................ 29

Risk and Vulnerability Assessment ...................................................................................... 29 

Design and Analysis ............................................................................................................. 29 

Prevention, Detection, and Surveillance............................................................................... 32 

Post-Event Assessment ......................................................................................................... 33 

Repair and Restoration.......................................................................................................... 34 

Evaluation and Training........................................................................................................ 35 

Others.................................................................................................................................... 35 

APPENDIX B RECOMMENDATIONS OF THE BLUE RIBBON PANEL 

FOR BRIDGE AND TUNNEL SECURITY ............................................................................ 37

OVERARCHING RECOMMENDATIONS.......................................................................... 37 

Institutional Recommendations ............................................................................................ 37 

Technical Recommendations................................................................................................ 37 

Fiscal Recommendations ...................................................................................................... 37 

Research and Development Recommendations.................................................................... 38 

APPENDIX C RESULTS FROM THE SECURITY WORKSHOP .................................... 41

Reducing the Vulnerability of the Nation’s Highway Systems............................................ 41 

Reducing the Risk of a Highway System Being Used as a Means to Attack ....................... 45 

Improving the Utility of the Highway Systems to Respond to and Recover 

From an Attack ..................................................................................................................... 48 

REFERENCES............................................................................................................................ 53
v 

LIST OF TABLES 

Table 1: Relationship between NCIP R&D theme areas and FHWA strategic focus areas......... 15 

Table 2: Research studies.............................................................................................................. 15 

1 

INTRODUCTION 

The Federal Highway Administration’s (FHWA) national security strategic goal is to improve 

highway security and support national defense mobility through collaboration with the 

Department of Homeland Security (DHS) and our State, local government, private sector, and 

other Federal Agency partners. FHWA has further developed four objectives to meet this 

security strategic goal: 

1. Develop a close working relationship with DHS and collaborate on establishment and 

implementation of highway-related security standards, administration of financial 

assistance for security initiatives, and distribution of threat and other sensitive security 

information to the highway industry. 

2. Support national disaster preparedness, and response and recovery efforts. 

3. Coordinate with our Nation’s military and transportation owners/operators to ensure 

adequate transportation facilities and operation in support of military deployment. 

4. Initiate and facilitate research and technology development in support of a more secure 

highway system 

This report, developed by the Office of Infrastructure Research and Development (R&D), 

proposes a plan addressing objectives 2 and 4 above. The plan focuses on bridge and tunnel 

security. R&D associated with securing other parts of our national highway system is being 

addressed by other offices within FHWA. 

It has been repeatedly stated that the surface transportation system is a resilient system, and 

except in a few major metropolitan areas and during peak periods, our national transportation 

network has significant redundancy (i.e., there are readily available alternate routes and alternate 

transportation modes). However, what is not so well documented is the enormous impact a 

damaged bridge or tunnel may have on a city, region, or possibly even the Nation’s economy. 

This is especially true if the restoration and reopening of the damaged structure and/or network 

were to take an extended period of time, which will typically be the case for major structures. 

Because terrorism is an unpredictable event, it is more appropriate to rely on layers of security 

rather than on a single measure. In the long run, however, to ensure continued functionality of 

the Nation’s physical infrastructure, it would be more appropriate to develop cost-effective 

designs utilizing improved materials, components, and structural systems, rather than relying 

solely on techniques for detection and surveillance. 

3 

SECTION 1: DEVELOPMENT OF A MULTIYEAR PROGRAM 

This report proposes an R&D program addressing highway bridge and tunnel security. In 

addition to securing the physical infrastructure, it is recognized that there is a need to protect the 

“info infrastructure” as increasing reliance is placed on information technology as a result of the 

greater role being played by intelligent transportation systems. FHWA and other agencies within 

the U.S. Department of Transportation (DOT) must work together to address high-priority, longterm, long-range research needs in this and other areas in order to develop appropriate solutions 

at the national level. 

Anticipating a multiyear program, FHWA initiated a number of efforts to identify research, 

development, and deployment needs for bridge and tunnel security. These efforts included a 

needs assessment, creation of a Blue Ribbon Panel, and conduct of a research needs workshop. 

The results of these activities are addressed below and form the multiyear bridge and tunnel 

security research program described herein. 

During this same time period, the FHWA Office of Infrastructure R&D was restructuring its 

bridge and structures research program to pursue a more strategically focused R&D agenda. 

Realizing the worsening conditions of our bridges and other highway structures because of 

normal daily use, FHWA set a vision to “get out in front of the bridge deterioration curve and 

stay there,” and to develop a strategy to conduct long-term, long-range research addressing: 

(1) design and construction needs to support development of the “Bridge of the Future”; 

(2) Stewardship and Management of our existing infrastructure; and (3) Safety, Reliability, and 

Security of both existing and future bridges and other highway structures. Therefore, when 

FHWA conducted a needs assessment, it included an outreach to both internal and external 

partners, customers, and stakeholders to help define gaps in knowledge and research needs 

within these three focus areas. 

Requests were sent to both internal and external groups within the bridge community seeking 

input in structuring the bridge and structures R&D program. Subsequently, a series of meetings 

were held at FHWA’s Turner-Fairbank Highway Research Center (TFHRC) where program 

managers and other invited FHWA offices assisted in refining the findings and restructuring the 

long-term R&D program. Results of this effort addressed needs in all three program focus areas. 

Presented herein are those needs addressing the security element of the bridge Safety, Reliability, 

and Security focus area. Although the discussion centers on bridge and tunnel security R&D, it 

should be realized that bridges and tunnels must be designed to withstand all hazards (natural 

and otherwise). 

FHWA envisions a multiyear program that will lead to bridges and structures that are resilient to 

all extreme events and threats. In order to develop a resilient physical infrastructure that can 

withstand acts of terrorism, FHWA must invest in developing better risk and vulnerability 

assessment methodologies, newer structural systems and improved analysis techniques, and 

improved materials. The program should be structured to find improved ways to prevent 

incidents; however, if an incident does occur, it must also provide better methodologies for 
4 

assessing the safety of damaged structures. Investments must also be made to develop rapid 

repair and restoration techniques. 

Overall, the program must encompass a wide range of topics that include systems analysis and 

design; improved materials; prevention, detection, and surveillance; post-event assessment, 

repair, and restoration; and evaluation and training. 
5 

SECTION 2: NEEDS ASSESSMENT, BLUE RIBBON PANEL, 

AND THE R&D SECURITY WORKSHOP 

BACKGROUND 

Needs Assessment 

An initial outreach effort was conducted in August 2002. Research needs were generated by 

soliciting potential research projects from participants. This was accomplished through e-mails 

summarizing the purpose of the outreach effort and the information requested. The e-mails were 

directed in two groups, one to internal FHWA bridge engineers and a second to individuals and 

organizations outside of FHWA. More than 60 research needs for bridge and structures security 

were identified. Program managers were asked to solicit input from constituents. Organizations 

such as the Transportation Research Board (TRB), the American Association of State Highway 

and Transportation Officials (AASHTO), and the American Society of Civil Engineers (ASCE) 

circulated the request to their members. 

Individuals in the following organizations and institutions were contacted as part of this outreach 

effort to determine research needs and gaps in knowledge in the security area: 

• Society of Fire Protection Engineers 

• Market Development Alliance 

• American Society of Civil Engineers 

• Building Futures Council 

• American Portland Cement Alliance 

• ITS America 

• Transportation Research Board 

• AASHTO 

• U.S. Army Corps of Engineers, 

Engineer R&D Center, ERDC 

• Pentagon Renovation Office 

• Federal Facilities Council 

• DOT, Research and Special Projects 

Administration 

• National Institute of Standards and 

Technology 

• Sandia National Laboratories 

• Oak Ridge National Laboratory 

• Caltrans 

• Los Alamos National Laboratory 

• Johns Hopkins University 

• Multidisciplinary Center for Earthquake 

Engineering Research 

• University of Texas 

• University of Washington 

• University of California at San Diego 

• Iowa State University 

• University of Michigan 

• University of Delaware 

• Drexel University 

• CH2M Hill 

• Intel Corporation 

• Modjeski and Masters, Inc. 

• Hardesty and Hanover, LLP 

• T.Y. Lin International 

• Wiss Janney Elstner Associates, Inc. 

• HDR Engineering, Inc. 

• FHWA, Office of Bridge Technology 

• FHWA, Division Offices and Resource 

Centers 
6 

Blue Ribbon Panel 

A Blue Ribbon Panel of bridge and tunnel experts representing professional practice, academia, 

and State and Federal agencies was convened to examine issues related to bridge and tunnel 

security, and to develop strategies and practices for deterring, disrupting, and mitigating potential 

attacks. Jointly sponsored by AASHTO and FHWA, and administered by TRB, the panel 

included: 

James E. Roberts

Consulting Bridge Engineer 

Imbsen and Associates, Inc. 

Dwight Beranek 

Deputy Director of Military Programs 

U.S. Army Corps of Engineers 

Joseph M. Englot 

Chief Structural Engineer 

Port Authority of NY and NJ 

John W. Fisher, Ph.D. 

Professor Emeritus 

Lehigh University 

Henry Hungerbeeler 

Former Director 

Missouri DOT 

Jeremy Isenberg, Ph.D. 

President and CEO 

Weidlinger Associates, Inc. 

John M. Kulicki, Ph.D. 

President, CEO, and Chief Engineer 

Modjeski and Masters, Inc. 

Frieder Seible, Ph.D. 

Dean, Jacobs School of Engineering 

University of California, San Diego 

Kenneth E. Stinson 

Chairman and CEO 

Peter Kiewit Sons’, Inc. 

Man Chung Tang, Ph.D. 

Chairman of the Board and Technical Director 

T.Y. Lin International 

Kary Witt 

Bridge Manager and Deputy General Manager 

Golden Gate Bridge, Highway and 

Transportation District 

In its report, Recommendations for Bridge and Tunnel Security, the Blue Ribbon Panel 

provides seven overarching recommendations in three areas—institutional, technical, and 

fiscal—required to accomplish the goal of reducing the vulnerability of bridges and tunnels 

to terrorist attacks. Recognizing that current design codes do not contain substantive 

information on how to employ hardening designs, quantify blast-related demands, and 

determine the capacity of components exposed to high-pressure transients, the report 

provides R&D recommendations for creating empirically validated computational tools, 

design methods, and hardening technologies. 

R&D Security Workshop 

FHWA held a workshop at TFHRC on March 3, 2004, to develop a strategic framework for 

R&D to improve security, focusing on highways and with an emphasis on longer range and 

more fundamental research needs. The product of this workshop was an unprioritized list of 

gaps and needs to help shape FHWA’s strategic plan for R&D. 

The workshop focused on three areas. The objective of each area was to identify gaps in 

current knowledge and technology that may prevent us from securing the Nation’s highway 
7 

system. The first area focused on reducing the vulnerability of the Nation’s highway system 

to attack, the second focused on reducing the risk of the highway system being used as a 

means to attack, and the third focused on improving the utility of the highway system to 

respond to and recover from an attack. 

A total of 34 participants, representing a very broad cross section of disciplines, agencies, 

offices, and stakeholders, were invited to the workshop. Attendees included: 

David Albright 

New Mexico DOT 

P.N. Balaguru 

National Science Foundation 

Rick Capka 

Federal Highway Administration 

Steven Chase 

Federal Highway Administration 

Ray Daddazio 

Weidlinger Associates, Inc. 

Fred Ducca 

Federal Highway Administration 

Sheila Rimal Duwadi 

Federal Highway Administration 

Steven L. Ernst 

Federal Highway Administration 

Brian Gardner 

Federal Highway Administration 

John Gerner 

Federal Highway Administration 

Monica Gourdine 

Federal Highway Administration 

Martin W. Hargrave 

Federal Highway Administration 

Amy Houser 

Federal Motor Carrier Safety 

Administration, R&T 

John Hoyt 

Department of Homeland Security 

Jeremy Isenberg 

Weidlinger Associates, Inc. 

Steve Jordan 

Woodward Communications 

Denny Judycki 

Federal Highway Administration 

Eva Lerner Lam 

Palisades Consulting Group 

Henry Lieu 

Federal Highway Administration 

Diane Liff 

Federal Highway Administration 

Michael P. Onder 

Federal Highway Administration 

Stephan Parker 

Transportation Research Board 

Vincent Pearce 

Federal Highway Administration 

Mary Lou Ralls 

Texas DOT 

James Ray 

U.S. Army Corps of Engineers 

Tamara Reid 

AASHTO 

John Rein 

Department of Homeland Security 

David Smith 

Federal Highway Administration 

Jim St. Pierre 

National Institute of Standards and 

Technology 

Paul Teng 

Federal Highway Administration 
8 

Maliek van Laar 

Woodward Communications 

Anthony Welch 

Federal Highway Administration 

Jeff Western 

Wisconsin DOT 

RESULTS 

These outreach efforts identified a variety of needs, research studies, and focus areas for securing 

our highways. As noted earlier, the needs assessment had an “all hazards” focus dealing with 

bridges and structures, while the work of the Blue Ribbon Panel concentrated on security issues 

and only those associated with bridges and tunnels, and the workshop concentrated on securing 

all highway transportation systems. Only those issues dealing with bridges and structures and 

with a security focus have been evaluated in developing the long-term program presented in this 

report. A summary of information resulting from the needs assessment, the Blue Ribbon Panel, 

and the workshop are given in appendixes A, B, and C, respectively. 
9 

SECTION 3: CURRENT PRACTICE AND 

GAPS IN KNOWLEDGE 

The events of September 11, 2001, helped bring into focus the need to protect our highway 

system against terrorist incidents. Prior to September 11, these threats had always been perceived 

as minor, and, as such, little attention was paid to designing for security. Although the threat has 

been realized, there is still a struggle to define strategies and solutions to protect our highways 

against terrorism. 

The larger civilian highway community has had little experience designing transportation 

infrastructure for security. Currently, our highway design codes and standards do not address 

loadings that might be experienced from terrorist activities, although research is slowly getting 

underway to change this. These issues, however, are not uncommon to the military. The military 

research community has long considered structural vulnerability of key structures in terms of 

how to attack those belonging to the enemy or how to make their own more resilient against 

enemy attack. The most complete experience with bridge vulnerability has come from numerous 

recent attacks of enemy bridges with large air-to-surface, precision-guided weapons. Much can 

be learned from these experiences; however, we can also reasonably assume that terrorist 

weapons would not be as sophisticated. Since the Oklahoma City bombing and attacks abroad on 

embassies, considerable work has also gone into the design of buildings for blast loadings. The 

U.S. Army Corps of Engineers (U.S. Army COE) has done considerable work in the area of 

conventional buildings and hardened structures subject to military weapons as well as terrorist 

attacks. The Department of State has supported considerable work in the area of blast/impactresistant barrier designs. Technologies from these areas can be expanded to determine the 

applicability to highway structures. 

In addition to bridges, the vulnerability of highway tunnels is an issue. The number of tunnels in 

the United States is growing because of a public preference for underground structures; the 

availability of better construction equipment and techniques; and the scarcity of above-ground 

space, especially in larger metropolitan areas. Highway tunnels are often considered to be 

relatively invulnerable to blast loadings, although there are major tunnels that may be highly 

susceptible to damage or collapse from a well-planned terrorist attack. A top priority in 

evaluating tunnel vulnerability to terrorist attacks is the threat of fire. Today, highway tunnels in 

the United States are designed in accordance with the National Fire Protection Association 502 

Standard for Road Tunnels, Bridges, and Other Limited-Access Highways. Although tunnels are 

designed for fire, and there are restrictions on carrying explosives or other hazardous materials 

into tunnels, these restrictions are irrelevant when dealing with terrorist actions. Large amounts 

of explosives are not easily obtained, but it is a simple matter for terrorists to hijack trucks 

transporting gasoline or other flammable materials, and ignite them in the middle of a long 

tunnel. Recent accidents in the Mount Blanc and English Channel tunnels have shown that an 

intense fire and the resulting smoke can be a major threat in tunnels, can cause heavy casualties, 

and shut a tunnel down for months. Flammable materials, such as gasoline, propane, methane, 

propylene oxide, etc., can cause a blast problem similar to high-explosive detonation, in addition 

to fire. 
10 

Although there is a wealth of knowledge to be gained from the military, the national laboratories, 

and also from the mining industry, etc., this information is pretty much unknown to the owners 

of our highway infrastructure. The needs assessments highlighted current gaps in knowledge in 

the areas of structural vulnerability to terrorist events, threat definition, structural loadings 

produced by these threats, possible attack locations, cost-benefit and risk assessment 

methodologies, post-event assessment strategies, and the need for rapid repair and restoration 

techniques. 

The ideas put forth during the workshop dealt with the overall transportation system. The need to 

develop a risk assessment methodology specific to highways was emphasized. Risk assessment 

methodologies are well developed and have been applied to many sectors for many years. 

However, there are many new and special aspects to the problem of applying existing 

methodologies to reduce the vulnerability of highways to attack. An essential input to a risk 

assessment is the event or scenario being analyzed. In the context of risk assessment of a terrorist 

or security event, the group felt that there was not adequate understanding of the “real” threats. 

Gathering and analysis of intelligence has not been a key competency or capability in the 

highway industry. This points to a need for better communication between those involved in the 

gathering of intelligence and those performing risk assessments. Validated models and tools, 

utilizing computer-based simulations, are needed to better analyze and quantify the consequences 

of and develop countermeasures to these threats. The need to develop improved surveillance and 

sensing technology to provide the data necessary to support the application of these advanced 

analysis and simulation tools was also identified as an area where research is needed. 

In terms of reducing the risk of the highway system being used as a means to attack, the majority 

of the ideas from the workshop could be grouped into three areas: (1) surveillance technologies 

and decision support, (2) application of such systems to cargo or freight tracking with an 

emphasis on hazardous materials management, and (3) socio-political issues. Sensing, 

surveillance, and decision support includes the development and use of sensors and surveillance 

technologies to detect threats, the integration of such technologies into command and control 

systems, and the actual use of such systems to reduce the threat of the highway system to deliver 

an attack and, at the same time, the use of these systems to improve the operational efficiency of 

the highways to move freight and improve the safety of hazardous materials shipments. There 

was at least an implied perception that freight movement, cargo, and hazardous materials issues 

represent the most important way in which the highway systems can be used to deliver an attack. 

In addition, the linkage of the highway system with the transportation systems of foreign 

countries is predominantly associated with freight and cargo movement. 

As for improving the utility of the highway system to respond to and recover from an incident, 

the workshop pointed out the need for better transportation management in a crisis situation, 

fundamental research in traffic flow in a crisis, and ability to communicate effectively during a 

crisis. Other issues identified dealt with decontamination of highway assets and vehicles after 

biological, chemical, or radiological exposure, and the need for rapid repair and restoration to 

have the ability to respond and recover from an incident. 
11 

SECTION 4: NATIONAL PLAN FOR R&D IN SUPPORT OF 

CRITICAL INFRASTRUCTURE PROTECTION 

Released by DHS and the White House Office of Science and Technology Policy (OSTP) in 

April 2005, this plan is the first annual version of the R&D roadmap for critical infrastructure 

protection required by Homeland Security Presidential Directive 7 (HSPD-7), Critical 

Infrastructure Identification, Prioritization, and Protection.

(1) The plan is national in scope, 

integrating cyber, physical, and human elements, and focuses on identification of capabilities, 

needs, and gaps based on known threats. The critical infrastructure per HSPD-7 includes the 

following sectors and key resources: Agriculture and Food; Water; Public Health and Healthcare; 

Emergency Services; the Defense Industrial Base; Information Technology; Telecommunications; Energy; Transportation Systems; Banking and Finance; Chemical Postal and 

Shipping; National Monuments and Icons; Dams; Government Facilities; Commercial Facilities; 

and Nuclear Reactors, Materials, and Waste. 

The HSPD-7 directive also requires the development of a National Infrastructure Protection Plan 

(NIPP). The development of the R&D plan was tasked to the Infrastructure Subcommittee of the 

National Science and Technology Council (NSTC), and was developed in coordination with the 

Interim NIPP released in February 2005. 

This first R&D plan focuses on two items: (1) the creation of a baseline, including the 

identification of major research and technology development efforts within Federal Agencies; 

and (2) the articulation of a vision that takes into account future needs and identifies research 

gaps based on known threats. Agency capabilities and near-term plans were mapped to R&D 

focus areas. FHWA and other agencies within DOT were involved in this process. 

The National Critical Infrastructure Protection (NCIP) R&D Plan is structured around nine 

themes: 

• Detection and sensor systems. 

• Protection and prevention. 

• Entry and access portals. 

• Insider threats. 

• Analysis and decision support systems. 

• Response, recovery, and reconstitution. 

• New and emerging threats and vulnerabilities. 

• Advanced infrastructure architectures and systems design. 

• Human and social issues. 
12 

The nine themes are to address three strategic goals: 

• National common operating picture for critical infrastructure. 

• Next-generation computing and communications network with security “designed in” and 

inherent in all elements rather than added after the fact. 

• Resilient, self-diagnosing, and self-healing physical and cyber infrastructure systems. 
13 

SECTION 5: PROPOSED FHWA MULTIYEAR PROGRAM 

FHWA envisions a multiyear program that addresses securing the existing infrastructure and that 

will lead to the next generation of bridges and structures that are resilient to this new threat. 

Terrorist threats to bridges can include: 

• Fire (can lead to buckling of steel beams and spalling of concrete). 

• Impact (can lead to damage of piers, causing collapse of the superstructure, and failure of 

hangers, again resulting in collapse of the superstructure). 

• Mechanical cutting devices (can lead to cutting of hangers, resulting in collapse of the 

superstructure). 

• Corrosive chemicals. 

• Blast or explosion (can lead to severe damage of the structure). 

Terrorist threats to tunnels can include: 

• Fire. 

• Impact. 

• Chemical/biological attack. 

• Blast/explosion. 

While we need to design for all threats, bombs constitute 60 percent of terrorist attacks 

worldwide. 

STRATEGIC FOCUS AREAS 

The proposed FHWA program focuses on the following strategic areas to reduce the threat of 

damage to the infrastructure so that there is minimal loss of life, the infrastructure can stay open 

for movement of people and goods, and there will be little or no impact on the economy. 

The recommended strategic focus areas for bridge and tunnel security R&D include: 

• Risk and Vulnerability Assessment. 

• System Analysis and Design. 

• Improved Materials. 

• Prevention, Detection, and Surveillance. 

• Post-Event Assessment. 

• Repair and Restoration. 

• Evaluation and Training.
14 

RESEARCH PROGRAM GOALS 

The following identifies the major goals for each of the seven strategic focus areas given above. 

Risk and Vulnerability Assessment 

Goal: Develop better decision support tools, and more relevant and uniform methodologies for 

assessing the risk to and vulnerability of the highway infrastructure. 

System Analysis and Design 

Goal: Develop new analysis and design methodologies for highway bridges and tunnels to 

minimize physical damage. 

Improved Materials 

Goal: Explore and develop new materials, and improve on current materials for the next 

generation of bridges and tunnels. 

Prevention, Detection, and Surveillance 

Goal: Adapt existing technologies and develop new technologies for better detection and 

surveillance and prevention of terrorist incidents. 

Post-Event Assessment 

Goal: Develop guidelines for assessing the safety of structures after an event. 

Repair and Restoration 

Goal: Develop better repair and restoration techniques to restore a structure to its original 

capacity. 

Evaluation and Training 

Goal: Test and evaluate new technologies, and develop training aids to transfer new 

technologies. 

TIE-IN TO THE NATIONAL CRITICAL INFRASTRUCTURE 

PROTECTION R&D PLAN 

Table 1 shows the relationship between the NCIP R&D theme areas and FHWA strategic focus 

areas. One of the goals of both plans is to have “resilient, self-diagnosing, and self-healing 

physical (and cyber) infrastructure systems.”
15 

Table 1: Relationship between NCIP R&D theme areas and FHWA strategic focus areas. 

FHWA Plan: Strategic Focus Areas 

NCIP R&D Theme Areas 

Risk and vulnerability assessment System analysis and design Improved materials Prevention, detection and surveillance Post-event assessment Rapid repair and restoration Evaluation and training 

Detection and sensor systems X X X 

Protection and prevention X X X X 

Entry and access portals 

Insider threats 

Analysis and decision support systems X X X 

Response, recovery, and reconstitution X X X 

New and emerging threats and vulnerabilities X X 

Advanced infrastructure architectures and 

systems design X X X X 

Human and social issues 

RESEARCH AND DEVELOPMENT RECOMMENDATIONS 

Based on analysis of the outreach efforts, the following R&D priorities were developed. This list 

should be revisited annually to ensure its continuing relevance and to update as necessary. 

The studies that have been or are close to being initiated by FHWA and others are italicized in 

table 2 and in the study descriptions that follow. 

Table 2: Research studies. 

Strategic Focus Areas FY03 FY04 FY05 FY06 FY07 FY08 FY09

Risk and Vulnerability Assessment

Synthesis of existing risk and vulnerability 

assessment methodologies 

 

Determination of levels of risk and probability of 

occurrence for each event, and development of 

consistent risk assessment methodology 

Development of criticality models for bridges and 

tunnels for incorporation into risk assessment 

models 

 

Lessons learned – Bridge demolition 

Guide to risk management of multimodal 

transportation infrastructure (NCHRP) 

 

System Analysis and Design

Standardized blast response curves for bridges 

(develop vulnerability curves to allow engineers to 

design appropriate standoff devices to mitigate 

these threats) (FHWA/U.S. Army COE) 

 
16 

Table 2: Research studies, continued. 

Strategic Focus Areas FY03 FY04 FY05 FY06 FY07 FY08 FY09

ConWep modifications for bridges 

(FHWA/U.S. Army COE)

 

Validation of numerical modeling and analysis of 

steel bridge towers subjected to blast loadings 

(FHWA/U.S. Army COE) 

 

Assessment of bridge designs for structural 

vulnerability against terrorist events 

 

Assessment of tunnel designs to resist blast and 

fire 

Optimized designs for hazard loadings 

Catalog of optimized design solutions for each 

event 

 

Advanced physical and numerical modeling and 

simulation capabilities for predicting and 

understanding behavior under extreme events 

Blast-resistant designs – Impact attenuators – 

Structural cladding 

 

Structural vulnerability guide 

Blast effects and retrofit techniques for tunnels 

Making transportation tunnels safe and secure 

(NCHRP) 

 

Better protection of piers against impact and/or 

blast loadings 

Blast testing of full-scale, precast, prestressed 

concrete girder bridges (WA State DOT) 

Blast-resistant highway bridges: Design and 

detailing guidelines (NCHRP) 

Improved Materials

Response modification devices 

Material performance under extreme event 

loadings 

 

Resistant materials and coatings for improved 

performance 

Shape-memory alloys for bridge structural 

applications 

Nanoscale science and engineering 

MEMS sensors research 

Prevention, Detection, and Surveillance

Synthesis of bridge and tunnel surveillance and 

security technologies (FHWA) 

 

Hazard mitigation measures 

Sensing and monitoring technologies for extreme 

events 

 

Post-Event Assessment

Forensic analysis of damaged structures to 

understand residual capacity and develop protocols 

for rapid assessment 

 

Inspection techniques for rapid safety assessment 

of damaged structures 

 

Damage assessment guide for extreme events 
17 

Table 2: Research studies, continued. 

Strategic Focus Areas FY03 FY04 FY05 FY06 FY07 FY08 FY09

Repair and Restoration

Emergency repair procedures 

Accelerated repair and restoration techniques for 

reconstruction after an event 

 

Evaluation and Training

Vulnerability Assessment Workshops 

(FHWA/U.S. Army COE) 

 

Institute a HITEC-type evaluation program for 

bridge and tunnel security technologies 

 

FHWA Engineering Assessment Team (FHWA) 

A short narrative is given below for most of these initiatives. 

Risk and Vulnerability Assessment 

Goal: Develop better decision support tools and more relevant methodologies for risk and 

vulnerability assessment. 

Synthesis of existing risk and vulnerability assessment methodologies: This project would have a 

multi-hazard approach. There is a need to develop consistency in the levels of risks used in 

design to safeguard structures from both natural and terrorist attacks. Designers apply different 

return intervals for various aspects of design, which may or may not relate to a consistent risk 

analysis. For flooding, roadways are allowed to overtop at return intervals anywhere from 10 to 

50 years, depending on the class of road. For seismic hazards, a 2500-year event is often selected 

for retrofit designs. For wind hazards, a 20-year occurrence event is selected for construction, a 

100-year event is used for strength, a 1000-year event is used for flutter during construction, and 

a 10,000-year event is used for flutter of the completed bridge. Currently, there is no basis for 

designing for security in the design codes and standards. A synthesis is needed to clarify the state 

of the practice and to determine the feasibility of reaching a consistent set of guidelines for 

evaluating risks and cost benefits for all hazards. This study would conduct a literature search 

and synthesize all available risk and vulnerability assessment methodologies for extreme events, 

including floods, wind events, earthquakes, blasts, overloads, and accidents (collisions, fires, 

etc.), and develop and recommend a framework for a consistent methodology for all extreme 

events. The literature search would also look at probability methods, such as those used in 

industrial reliability. The resulting document and recommended framework will be used by 

FHWA for developing a single risk and vulnerability methodology for all extreme events 

encountered by the Nation’s highway bridges and tunnels. 

Determination of levels of risk and probability of occurrence for each event, and development of 

consistent risk assessment methodology: This project would conduct a broad investigation and 

identify acceptable risk levels in designing for each hazard type and the basis for their use. It 

would identify recurrence interval or probability of occurrence for each extreme event for each 

risk level. It would study the patterns of recurrence and how well each method has worked, as 

well as the economic costs incurred after using the method. The extent of loss of life would also 

be researched. The project would recommend if a single set of consistent levels of risk for all 
18 

hazards is feasible. This study would start with analyzing results from separate analyses of 

individual hazards, selecting the level most likely to be satisfactory, and then comparing the 

projected effects of the new design events to those in use to determine if safety and cost are 

increased or reduced. Finally, this study would develop a risk assessment methodology utilizing 

the framework developed in the previous study. 

Development of criticality models for bridges and tunnels for incorporation into risk assessment 

models: This study will add to the developed risk assessment methodology by providing 

criticality models for different events for each risk category. 

Lessons learned – Bridge demolition: This study would gather pertinent information from 

demolition companies on demolitions of structures in order to learn from their experiences. The 

goal would be to learn the difficulty and ease of the job; explosives needed (how much, what 

type, shape and location of placement; analytical approaches used; software type; time on target 

required, etc.). 

Guide to risk management of multimodal transportation infrastructure (NCHRP): This National 

Cooperative Highway Research Program (NCHRP) study is developing a guide that will provide 

State DOTs and other transportation entities with a risk management methodology that can be 

used to conduct threat, vulnerability, and criticality assessments of their facilities and to 

determine cost-effective countermeasures to prevent, detect, and reduce threats to assets on a 

multimodal basis. The product of this project will be a recommended replacement to the 2002 

AASHTO Guide to Highway Vulnerability Assessment for Critical Identification and Protection. 

System Analysis and Design 

Goal: Develop new analysis and design methodologies for highway bridges and tunnels to 

minimize physical damage. 

Assessment of bridge designs for structural vulnerability against terrorist events: The goal of this 

project would be to investigate and identify key components of each bridge design type for 

vulnerability to blast loadings, fire, and intentional impact. A summary of activities may involve 

collecting common bridge designs from State highway agencies, such as the designs of 

representative I-girder, box girder, suspension, cable-stayed, curved girder, and slab-type 

bridges; categorizing hazard loadings into different levels or classes; reviewing and assessing 

each bridge design type subjected to the different levels or classes of hazard loadings; identifying 

vulnerable details; and recommending design solutions and/or vulnerable elements requiring 

further study. This study would also look at where information exits, past performances of 

bridges during these events. This may include gaining access to infrastructure performance from 

the military from bombings in wars, military combat demolition, and military research. Although 

the types of ammunition used by the terrorists would most likely not be as sophisticated, much 

can be learned about the vulnerability of bridges from this available data. The expected products 

would be a document identifying vulnerable details and recommended solutions for each bridge 

design type and recommendations for future work. This study would be followed by subsequent 

studies to develop optimized designs and countermeasures for mitigating and hardening 

structures for extreme events. 
19 

Assessment of tunnel designs to resist blast and fire: This project would parallel the above 

project, but would concentrate on tunnels. The goal would be to investigate and identify key 

components of tunnel design for vulnerability to blast and fire. Activities may involve collecting 

tunnel design types, including soil conditions; categorizing hazard loadings into different levels 

or classes of loadings; review and analysis of each design type, subjecting each to the different 

levels or classes of hazard loadings; determining the weaknesses of each type; and 

recommending design solutions. This study would also look at, where information exits, past 

performances of tunnels during these events. This may include gaining access to the military on 

performance of tunnels from bombings in wars, military combat demolition, and military 

research. Although the types of ammunition used by the terrorists would most likely not be as 

sophisticated, much can be learned about the vulnerability of tunnels from this available data. 

The expected products would be a document identifying vulnerable details, recommended 

solutions for each tunnel design type, and recommendations for future work. 

Making transportation tunnels safe and secure (NCHRP): The objective of this NCHRP research 

study is to develop safety and security guidelines for owners and operators of transportation 

tunnels to use to identify: (1) critical locations; (2) potential structural improvements; 

(3) operational countermeasures; and (4) deployable, integrated systems for command, control, 

communications, and information. The guidelines are to be applicable across the spectrum of 

both accidental and intentional threats. 

Optimized designs for hazard loadings: This would involve multiple studies to develop design 

solutions for vulnerable designs, details, or weaknesses identified in the previous studies. It 

involves tailoring vulnerable details of structures for mitigating the consequences of a blast, 

utilizing improved fire-resistant materials and designs, and designing solutions for resisting 

vehicle and vessel collisions for vulnerable structures. 

Catalog of optimized design solutions for each event: This project would compile into one 

document all optimized design solutions for each extreme event. It would be a “how to design 

for ...” manual with illustrations and information on what and what not to do for the bridge 

designer. 

Advanced physical and numerical modeling and simulation capabilities for predicting and 

understanding behavior under extreme events: This study would develop analytical capabilities 

to be used for predicting the behavior of structures under extreme events. The product would be 

of use to researchers, code developers, and bridge designers for making decisions in lieu of 

experimental tests. 

Blast-resistant designs – Impact attenuators – Structural cladding: Following the Oklahoma City 

bombing, the General Services Administration (GSA) developed a series of bomb-blast 

requirements for buildings. For example, the Federal Aviation Administration’s Eastern Regional 

Headquarters building in Queens, NY, utilizes precast panels that meet the GSA’s requirements. 

Basically, it is a self-supporting building structure built within a self-supporting facade. The 

walls provide the blast-zone loading with the concrete and steel reinforcing stressed within the 

elastic range. These walls are the primary protective elements that provide resistance in case of 

an explosion and are considered “hardened elements.” The cladding used outside these walls 

consists of precast concrete architectural panels with laid-up brick. The facade is only nominally 
20 

supported by the concrete frame. They designed a bunker-type structure, but clad it with precast 

concrete and brick in such a way that it absorbs the initial force of a blast. There is a 101.6-

millimeter (4-inch) gap between the building’s architectural features and structural elements. The 

goal of the precast concrete is not to be protective to an exterior explosion, but to “peel away” in 

case of a bomb blast, providing protection and absorbing force. It takes the first hit and absorbs 

some of the force, minimizing damage that could be caused by collapsing. The backup concrete 

wall then takes most of the force. The precast concrete serves as a “crumple zone” to protect the 

rest of the structure. 

A study should be conducted to determine the feasibility of using this or similar design concepts 

for critical components of bridges and tunnels, such as piers, pylons, towers, tunnel walls, etc. 

Using this concept, one could make the cladding sacrificial and save the structure. If determined 

to be feasible, second and subsequent phases could be initiated to develop the concept further 

and to test on actual bridge and tunnel critical components. 

Blast-resistant highway bridges: Design and detailing guidelines: This NCHRP study involves 

developing guidelines for selecting analysis techniques and developing design and detailing 

guidelines, evaluating approaches to enhancing the performance of bridges subjected to blast 

loads, and developing guide specifications and a procedure for assessing bridge damage caused 

by explosions. 

Structural vulnerability guide: Currently, there are no guidelines, specifications, tools, or 

experience to determine the structural vulnerability of infrastructure (bridges and tunnels) to 

terrorism. The AASHTO Guide to Highway Vulnerability Assessment deals more with 

susceptibility to an attack based on location and the importance of the structure. The FHWA/U.S. 

Army COE’s Bridge and Tunnel Vulnerability Workshop deals with structural vulnerability in an 

attack because of blast loadings, irrespective of the location. The material for the workshop is 

based on the U.S. Army COE’s experience with infrastructure research to support the military’s 

objectives. According to the U.S. Army COE, little or no research has been done in the specific 

area of terrorist threats against bridges and tunnels. Numerous Federal Agencies conduct R&D 

on security measures against hostile attacks. R&D in related areas, particularly protection against 

natural disasters and accidents, may also be effective in preventing the destruction of structures 

from hostile attacks. This project would explore these areas to determine applicability to 

highway structures and to develop a structural vulnerability guide. 

Blast effects and retrofit techniques for tunnels: Research to determine blast effects and to 

develop retrofit techniques may be needed for some tunnel types, especially those on soft or poor 

soils, underwater, and cut and cover tunnels. There may also be a need to look at improving 

ventilation systems, designing systems for mass evacuations, etc. Based on what was presented 

at the U.S. Army COE’s Bridge and Tunnel Vulnerability Workshop, numerous explosive tests 

have been conducted for the military on tunnel design systems anticipated by the military. 

Almost all of these, however, have been on one-way tunnels (i.e., there is only one entrance in 

and out of the tunnel). These tunnels are used to store ammunition and as shelters, not for 

moving people. Some of these tunnels also have berms in front of the entrances, which can 

mitigate the blast energy. As such, the current research data possibly would not be applicable to 

vehicular tunnels. If an explosive is detonated in a vehicular tunnel, the blast energy has clear 

exits in two directions; therefore, the reflection waves might even be less. This project would 
21 

determine the blast effects on vehicular tunnels and develop retrofit techniques through analysis 

and testing. 

Standardized blast response curves for bridges: This study is developing simple design aids to 

help engineers design bridges for blast loadings. The study will produce a standardized set of 

blast response curves for a generic set of common bridge elements, including decks exposed to 

deck-top detonations, steel and prestressed girders exposed to deck-top detonations, rectangular 

and wall-type piers exposed to side-on detonations, and a single-cell tower of a cable-stayed 

bridge exposed to side-on deck-level detonations. 

Bridge-specific blast loading program: This study is developing a user-friendly computer 

program for consistent definition of blast loadings on bridges. The U.S. Army COE’s current 

computer program, ConWep (Conventional Weapons Effects), is widely used within the 

engineering community to predict blast loadings on structures from conventional weapons, 

including terrorist-type vehicular bombs. This program was originally developed as an expedient 

and user-friendly tool for engineers concerned mostly with building structures. The graphical 

user interface (GUI) of this program will be modified to better facilitate bridge-specific 

problems. It will develop a user-friendly and bridge-specific GUI for reliable definition of key 

parameters such as weapon size, weapon standoff, weapon orientation in relation to the structural 

element, the overall size of the structure, and the size of the responding element of interest.

Validation of numerical modeling and analysis of steel bridge towers subjected to blast loadings: 

Most major long-span bridges in the United States are vulnerable to terrorism. They are highvisibility structures, with a potential for extensive media exposure and public reaction if an 

incident were to occur. As a result of the long spans, complicated designs, site locations, etc., 

these bridges have very high replacement costs and multiyear replacement construction periods. 

The potential for impacting regional and national economies is also greater because of the 

increased time for reconstruction. Many of these bridges serve as transportation arteries critical 

for emergency evacuation and for carrying lifelines besides vehicular traffic. This study will 

develop several numerical models and analysis validated through the construction of physical 

models subjected to large explosive devices detonated to determine the actual behavior of such 

towers. This study will further develop and test several hardening concepts for cellular steel 

bridge towers so that the performance of these towers can be well understood in the event of 

such an attack occurring after the hardening has been implemented. 

Blast testing of full-scale, precast, prestressed concrete girder bridges: This study will: 

(1) assess the damage done to precast, prestressed girder bridges from a blast generated below 

the girders, (2) compare this damage with a blast generated on top of the bridge deck, and 

(3) develop recommendations for possible mitigation measures that would harden this type of 

bridge blast damage. Precast, prestressed concrete girder bridges are the most prevalent bridge 

design in the country. 
22 

Material Performance 

Goal: Explore and develop new materials, and improve on current materials for the next 

generation of bridges and tunnels. 

Response modification devices: This projects aims to develop and refine response modification 

devices such as dampers, isolation bearings, yielding devices, and shape-memory alloys. This 

project would also look into developing cladding systems that take the initial impact and thereby 

lessen the load on the main members. The project would take a multi-hazard approach in 

developing devices for hazard mitigation. 

Material performance under extreme event loadings: The behavior of construction materials in 

bridges subjected to fire is a critical issue that has not been addressed adequately in the past. The 

behavior of new high-performance materials is even less understood, and the enhanced material 

characteristics may be even less suited for high-intensity fires, such as a burning tanker truck 

carrying liquid petroleum. Although accidents involving trucks carrying hazardous materials are 

a common occurrence, the risk is amplified as a result of terrorism. As a first step toward 

developing fire-resistant construction materials and protective coatings, the performance of both 

normal-strength and high-performance steel and concrete during a fire needs to be assessed. This 

study should lead to a better understanding of the performance of materials during explosive 

loadings and fires. The study would include materials such as normal-strength and highperformance steel and concrete. It would determine how much blast material (energy) and heat 

are needed to damage a structure constructed of these materials so that the structure is no longer 

functional. This information could be used to determine design loads and also design mitigation 

measures. If the load required to damage a structure is unreasonable, this would also let you 

know that nothing needs to be done. 

Resistant materials and coatings for improved performance: This study aims to develop materials 

and coating systems that can be applied to highway structures that can resist high-intensity fires 

and absorb blast loadings. 

Shape-memory alloys for bridge structural applications: Shape-memory alloys are metallic 

composite materials capable of changing shape and returning to their original form after stresses 

have been removed. These materials have been in existence for more than 30 years. Structures 

made of these materials hold promise for possessing energy-absorbing capabilities, enabling 

them to sustain high-velocity impacts or explosions. The materials hold promise for resisting 

seismic, blast, and high-impact loadings. Although some research is being conducted, most is 

concentrated on the seismic issue. This study would assess these alloys for mitigating terroristtype loadings. 

Nanoscale science and engineering research: Nanoscale science and engineering represents an 

opportunity to engineer materials/devices with novel characteristics. At approximately 1 to 100 

nanometers (a nanometer is equal to one-billionth of a meter), clusters of atoms and molecules 

exhibit properties very different from those found at larger scales. Nanoscience is the creation of 

new materials, devices, and systems at the molecular level. It can significantly improve 

mechanical, optical, chemical, and electrical properties. Through nanoscience, it is possible to 

create ductile ceramics. Nanoscience materials enable radical design changes. The National 
23 

Nanotechnology Initiative is a White House initiative involving 10 agencies. TFHRC, through its 

Advanced Research Program, has a number of research studies in this area. The possibility of 

protecting structures against terrorist threats through the use of nanotechnology by providing 

new designs, new materials, and blast-resistant structures is a new area that should be explored. 

This would be long-range, high-risk research with the potential for a high payoff. 

Nanoscience research areas include: 

• Materials that perform well under extreme conditions of temperature and pressure. These 

can be strong, tough, ductile, lightweight, and low-failure materials. 

• Smart materials such as paints that change color with temperature. 

• Radiation-tolerant materials. 

• Self-healing materials: Research is ongoing at the National Aeronautics and Space 

Administration’s Langley Research Center on self-healing materials development to 

develop materials that will mend themselves if subjected to high-velocity projectile 

penetration. This technology has the potential for structural applications in bridges. 

Nanoscale self-healing materials can be developed to be embedded in structural materials 

that become activated at the site of a fracture, etc., and self-heal the material. 

Nanotechnology can be used to build stronger, lighter, and harder materials as has already been 

done in the aerospace industry. 

MEMS sensors research: Research into micro-electro-mechanical systems (MEMS) would be 

another high-risk, high-payoff research. Its application in structures can include structural 

monitoring and structural control, nondestructive evaluation, and materials engineering and 

analysis. MEMS sensors can be used to measure physical properties (temperature, pressure, 

strain, magnetism, etc.) and inertial properties (vibration, tilt, acceleration, and velocity); for 

chemical and particle detection, and range and motion detection; and for imaging. Examples of 

these sensors include silicon accelerometer, silicon gyro, micro-hotplate chemical sensors, and 

ion-mobility spectrometer and pressure sensors. 

MEM sensors can be used to design for security. They are already a key element in improving 

the performance of concrete. Cyberliths are complete monitoring and telemetry systems on a 

chip that can be embedded in artificial pebbles and thrown in with the aggregates during the 

mixing of concrete. More sophisticated cyberliths could be developed to measure stress 

distributions. MEM methods have been applied to manufacture thousands of miniature ultrasonic 

transducers on a single chip. It is more powerful than conventional transducers and enables 

inspection by noncontact, nondestructive technology. MEM actuators can be used at selected 

locations to control structural vibrations. Nanosensors embedded in cables, piers, pylons, and 

decks could sense imminent danger or collapse and alert engineers. Nanosensors embedded at 

various locations on a structure could act as the “brain” of the bridge and alert authorities to 

multiple hazards. 
24 

Prevention, Monitoring, Detection, and Surveillance 

Goal: Adapt existing technologies and develop new technologies for better monitoring, 

detection, surveillance, and prevention of incidents, catastrophic failures, and/or condition 

assessment. 

Synthesis of bridge surveillance and security techniques: This study is synthesizing the state-ofthe-art practices related to surveillance and security of our bridge structures, and developing an 

evaluation framework to select among alternative surveillance and security approaches. 

Hazard mitigation measures: This project would include studies to develop countermeasures for 

mitigating hazards. It would include blast mitigations systems and impact absorption devices. 

Sensing and monitoring technologies for extreme events: This project would develop sensing and 

monitoring technologies that can be incorporated into our bridges and structures to monitor 

performance during extreme events, detect intruders, and help assess the post-event capacity of 

structures. It would include developing monitoring and warning devices to prevent vehicle 

collisions on bridge girders and vessel collisions at bridge piers. It would also include developing 

monitoring and warning devices to predict bridge scour, movement of bridge piers, and 

aerodynamic instability. 

Post-Event Assessment 

Goal: Develop guidelines and methodologies for assessing the safety of structures after an event. 

Forensic analysis of damaged structures to understand residual capacity and develop protocols 

for rapid assessment: The ultimate goal of this project would be to develop an inspection 

protocol/checklist to be followed in assessing structural safety, which can be done rapidly in 

times of crisis. The first step might be to compile a report or synthesis of “bridge morphology.” 

This should be a complete listing of all bridge failures, collapses, and demolition. The purpose is 

to obtain a broad view of what can happen to a bridge. The next study would expand our interest 

to include major damage to bridges. After determining the most likely incidents, conduct an 

analytical and experimental study of damaged structures to determine their remaining capacity 

and to understand how and why the damage occurred. The study will require a literature search 

of the subject and an exhaustive study of reports on past damaging events. Then it will be 

necessary to develop analytical and laboratory models of the damaged parts of the structures for 

further testing. It may also be possible to obtain portions of old or damaged bridges for the 

laboratory tests. Once the testing is done, develop new protocols for assessing damage and 

remaining strength. 

Inspection techniques for rapid safety assessment of damaged structures: In times of crisis, being 

able to rapidly determine the residual strength of structural members is crucial. This study would 

develop nondestructive evaluation techniques/capabilities to assist the structural engineer in 

determining the residual capacity of damaged structures. 

Damage assessment guide for extreme events: This study would produce a field guide based on 

the results of previous studies for the assessment of structures for damage from extreme event 

loadings. It would develop guidance on emergency stabilization analysis; failure investigation; 
25 

material strength evaluation; and determination of which areas are safe and which areas need to 

be demolished, and which methods should be used for demolition. 

Repair and Restoration 

Goal: Develop better repair and restoration techniques to restore a structure to its original 

capacity.

Emergency repair procedures: Studies on this will require an idea of the types and levels of 

damage that are expected. This would have to be done as part of system analysis and design, 

probably as a study (or studies) under assessment of current bridge and tunnel designs for 

structural vulnerability to multiple hazards. There would be studies to determine the damage 

expected under various single hazards. The next step would be to predict the damage caused by 

two or more simultaneous events. This information could be used as a starting point in 

identifying and/or developing emergency repair procedures. Once we know the nature of the 

damage to be expected, repairs can be developed. As a start, this would involve shoring, 

temporary spans, precast or prefabricated members, and also repairs to damaged members that 

have retained considerable strength and are salvageable. The study should also find other ways to 

repair or replace damaged members and keep traffic flowing. Maintenance and protection of 

traffic should be an integral part of these studies. 

Accelerated repair and restoration techniques for reconstruction after an event: These studies will 

complement and flesh out the emergency repair procedures covered above. Accelerated methods 

are a must for emergency repair procedures. In fact, except for routine maintenance, most repair 

procedures should be accelerated since they usually interfere with traffic or are executed under 

difficult physical conditions. Application and monitoring of innovative concepts for repair or 

replacement complete this study. Considering the demands in terms of working rapidly and 

fixing weakened members, developing and deploying innovative procedures is another must. 

27 

SECTION 6: SUMMARY 

Protecting critical infrastructure against terrorist events is a need imposed on us by the events of 

September 11, 2001. Although the transportation community has always responded to natural 

hazards (and there are procedures in place to design for and handle these), managing for terrorist 

events presents a new challenge. FHWA has been proactive by reaching out to stakeholders to 

identify critical gaps and needs. This has been accomplished through several forums as presented 

in this report. The input provided by experts in the field of bridge engineering and others has 

been evaluated and a program has been proposed to design highway bridges and tunnels for 

security. There are studies underway addressing some of these needs, but most of these are 

narrow in scope and additional studies need to be conducted to close the gaps. It is recognized 

that additional high-priority projects may surface as research is completed and that identification 

of critical needs is a dynamic process. 

29 

APPENDIX A 

RESEARCH NEEDS FROM NEEDS ASSESSMENT 

Risk and Vulnerability Assessment 

1. Because the ways in which a terrorist could potentially attack a bridge are numerous and 

highly varied, and the possibilities are limitless if the bounds of reason and probability are 

not applied, we must first have a threat definition. The results of a decade of effort by our 

country, as well as others, in defining the most probable terrorist threats against military 

structures, embassies, etc., can be used as a starting point for defining threats against 

bridges. 

2. Cost-benefit and risk-assessment methodologies must be developed to economically address 

all terrorist threats against bridges, as there are many different bridge types and different 

degrees of damage depending on the bridge type. 

3. Develop methodology to conduct consequence analysis (e.g., how to assess the possible 

consequences of a truck bomb exploding near a critical member on the bridge). 

4. Vulnerability prediction tools: Once the loadings, damage mechanisms, and residual 

strengths of bridge elements are better understood, these results should be incorporated into 

new and/or existing vulnerability prediction tools. 

5. It is proposed that a research effort be performed to establish guidelines for evaluating the 

vulnerability of transportation tunnels to terrorist threats. The guidelines will be developed 

from the latest state of the technology with regard to tunnel structural damage from 

explosions, the propagation of blast pressures and thermal effects in tunnel systems, and fire 

or blast control and mitigation techniques for underground facilities. The guidelines will be 

provided in a user-friendly, AT-Planner type computer format, and will allow users to: 

6. Determine which tunnels are structurally vulnerable to terrorist attacks and which are not. 

7. Threat vs. risk definition: Prior to any detailed efforts to define specific bridge 

vulnerabilities, specific terrorist threats and the probability of occurrence (i.e., risk) for each 

threat must be defined. Definitions of the most probable threats are required in terms of type, 

size, and location on the bridge. Threat types considered should, at a minimum, include 

vehicle or boat bombs, hand-carried bombs (e.g., briefcase, etc.), precision cutting charges 

(i.e., shaped charges), kinetic energy threats such as vehicle or airplane impact, and fire. The 

size of the threat can range from a hand-cartable weight all the way up to that carried in a 

tractor-trailer vehicle. 

8. Guidelines for evaluating credible threats (e.g., is a truck bomb probable/credible?, is a 

shaped charge probable/credible?, is a ship/barge impact probable/credible?, etc.). 

Design and Analysis 

9. Impact dampening designs. 
30 

10. Bridge types and design features less prone to damage from terrorist attack. 

11. Develop more nonlinear inelastic design approaches, taking advantage of structural ductility. 

12. Better protection of piers against impact and/or blast loadings. 

13. Use of more continuous structures. 

14. Use of redundancy in structures. 

15. Deterrent effects of layered countermeasures. 

16. Additional knowledge and understanding of the influence of member geometry on local 

performance under blast conditions. 

17. Additional knowledge and understanding of the influence of the structural system on global 

performance under blast conditions. 

18. Although for large suspension cables the likelihood is low that the cable could be severed or 

even lose enough capacity to cause bridge collapse, the cable size (which is related to bridge 

size) below which this would be a very serious problem needs to be defined. The 

vulnerability of the smaller diameter intermediate cable is also unknown. Another concern 

for cable hangers is the number of successive hangers that would need to be removed in 

order to induce a spontaneous “unzipping” of the remaining hangers because of load 

redistribution. 

19. Development of guides for proper protection of end anchorages of suspension cables. 

20. Simple threat vs. required standoff distances (i.e., vulnerability curves) are required to aid 

engineers in mitigating the threat of bomb blasts on structures both above and below the 

decks of bridges. Vulnerability curves should also be developed for the typical truss 

elements of a through truss or through arch bridge. 

21. The intermediate supports (piers and bents) for any type of bridge span could be vulnerable 

to blast loadings (vehicle or boat bombs). The smaller column portion of bents will be the 

most vulnerable to lateral loadings from adjacent blasts. Again, vulnerability curves need to 

be developed for typical piers to allow engineers to design appropriate standoff devices to 

mitigate these threats. 

22. In the specific area of bridges, the U.S. Army Corps of Engineers’ Engineer Research and 

Development Center (ERDC) recently developed a computer code, entitled Bridge Analysis 

System (BAS), for smart targeting of bridges with precision-guided, air-to-surface weapons. 

The BAS development effort included a thorough search of international literature in the 

areas of weapon effects against bridges and structural response of bridges subjected to blast 

and fragment loadings. A large amount of bridge attack/damage data was also collected 

from recent U.S. military actions, including Iraq, Bosnia, and Serbia. A key part of the BAS 

is a weapon effects database, which is weapon specific and predicts the level of damage 

imparted to the bridge structural elements based on the weapon’s impact conditions and the 

location on the bridge. The database was developed at the ERDC using dynamic finite 

element (FE) analyses of steel and reinforced-concrete structural elements (beams and 

girders) impacted by a combination of blast and fragment loadings. The methodology 

developed for the definition and application of combined blast and fragment loadings on FE 

models was very innovative and represents the state of the art in this area. 
31 

23. Simplified analytical techniques are insufficient to properly study the structural vulnerability 

of cable-supported towers. Detailed analyses should be accomplished using hydrocodes to 

predict the complex blast loadings, coupled with FE models of the towers with all in situ 

loadings present. 

24. Development of guidelines for sizing members to enhance bridge performance under blast 

conditions. 

25. Design of concrete structures using fracture mechanics principles rather than static loading 

criteria. 

26. Determination of design safety factors appropriate for dynamic and blast loading 

applications. 

27. Better protection of the bearings, shoes, etc., of suspension and cable-stayed bridges. 

28. The application of systems engineering and the availability of advanced technologies have 

made it clear that earthquake hazard mitigation effects should be considered in combination 

with other natural and manmade disasters. By the same logic, highway systems are 

interconnected with other modes of transportation. It may be useful for FHWA to point out 

that advanced technologies from FHWA can be extended to facilitate the intermodal 

transportation needs of the public. 

29. Damage and strength reduction to generic structural elements: Many of the technology 

shortfalls involve explosive loadings on key structural elements of specific bridge types 

(e.g., decks, girders, piers, etc.). Many of these elements are similar in nature and carefully 

planned studies of generic elements can address many bridge types at once. These studies 

should encompass a carefully planned combination of simplified analyses, detailed analyses, 

and actual testing. The residual load capacity of the damaged elements should also be 

studied in a similar manner. As controlled explosive tests on bridge elements have been 

almost non-existent in the past, testing should be a priority, even if only done on a limited 

basis. 

30. Structural loadings from terrorist threats: The loadings from blast-type threats must be 

defined in terms of airblast magnitudes and durations, and fragment densities and velocities. 

Kinetic energy impactors must be defined in terms of mass, velocity, and impact locations. 

These definitions may be accomplished through a combination of full- and reduced-scale 

field tests and analytical modeling. Existing predictive computer codes for military weapons 

can then be modified to include terrorist weapons. 

31. Vulnerability of specific bridge types: As the research progresses, it will probably become 

apparent that some bridge types, such as truss bridges, need to be studied as a complete 

structural system rather than as individual structural components. These studies will include 

detailed analytical calculations using the results from tasks 2 and 3 above and may involve 

limited field tests of actual bridge structures. As field tests of entire bridge structures will be 

very costly, these will only be done as a last resort to analytical modeling. 

32. Identify critical locations for possible placement of explosive charges. 

33. Determine the potential extent and type of damage as a function of the tunnel design and the 

explosive charge size. 
32 

34. Determine the airblast and vehicle damage levels that would occur at any point in the tunnel 

as a function of the threat (charge size and location). 

35. Identify possible protection methods to reduce casualties/damage. 

Prevention, Detection, and Surveillance 

36. Threat reduction/mitigation measures: As the research progresses, the true vulnerability of 

specific bridges and bridge elements will become apparent. This will allow for the 

development of threat reduction/mitigation measures such as standoff devices, intrusion 

prevention doors, fragment protection panels for beams and cables, blast-resistant design 

detailing, etc. 

37. Consider intrusion detection monitoring for major structures. 

38. Detection and warning systems to prevent dangerous cargo from getting into tunnels. 

39. Classify major structures and coordinate with the Department of Defense to monitor by 

satellite. 

40. Identify bridge surveillance and security technologies. 

41. Use of global information system (GIS) technology to safeguard critical structures, record 

current road network conditions, etc. 

42. Global positioning system (GPS)-based systems: Increased reliance on GPS-based systems 

for communication with many transportation systems in the United States could compromise 

traveler safety in the event of signal disruption. That is the conclusion of a study by the 

Volpe Transportation Center in a report entitled Vulnerability Assessment of the 

Transportation Infrastructure Relying on the Global Positioning System (www.navcen.uscg. 

gov/news/FinalReport-v4.6.pdf). GPS technology can be adversely affected by atmospheric 

effects, signal blockages from structures, interference from other signals, and deliberate 

disruptions. Although of primary concern to the aviation industry, other modes of 

transportation are increasingly relying on GPS technology for everything from tracking to 

traffic management. The report recommends that the State DOTs create an awareness of 

GPS vulnerabilities, improve their backup systems, and install monitoring systems to warn 

users of interference with GPS signals. 

43. Means of protecting traffic control systems from physical and cyber attacks. 

44. Real-time chemical sensors. 

45. Neutralizing agents and robots that can test areas and perform decontamination. 

46. Deterrent effects of tactics to create uncertainty (“curtains of mystery”). 

47. Explosive detection systems able to detect a wider range of materials. 

48. Means to network and combine sensors into “sensor fusion.” 

49. Standoff and accurate field sensors with low rates of false alarms. 

50. Development of guidelines for restricting access to critical bridge members. 
33 

51. Determine when and how to take mitigative measures – surveillance and intervention (e.g., 

physical barrier coming up), hardening critical members, limiting truck operations along 

critical lanes, etc. 

52. Provide guidelines for the design of surveillance systems, including the kind of system, 

location, etc. 

53. Detection of dirty bombs in tunnels through the use of sensors. Determine if there is a 

justifiable need or a practical method for detecting dirty bombs on a continuous basis. 

54. Monitoring of structural performance to detect problems and prevent the occurrence of 

critical situations. 

55. Development of an active safety system for critical transportation facilities that could stop a 

suspect vehicle traveling on a structure. 

56. Use of remote-sensing, space-based observation systems to assist in a variety of ways in 

improving transportation security. Identifying and reducing vulnerabilities through the use 

of remote-sensing technologies would help security professionals protect our vast 

transportation system. Our recommendations to DOT call for establishing interoperability 

standards for remote-sensing transportation information, which will then be used by security 

officials at the Federal, State, and local levels. 

57. Remote sensing is the process of employing electronic cameras or other types of sensors to 

image a subject or sense its presence and composition at a distance from the subject. A 

digital camera and a radar detector are both simple forms of remote-sensing technologies. 

Sensors may be mounted on satellites, aircraft, or on ground-based platforms. For example, 

the Landsat satellite system, developed by NASA, has been collecting remotely sensed 

images of the Earth for more than 30 years. A report is available based on a workshop 

convened at George Washington University by the National Consortium for Safety, Hazards, 

and Disaster Assessment for Transportation Lifelines (NCRST-H) in order to effectively 

assist transportation officials to meet the threat of terrorist activities throughout the country. 

In addition to identifying potential applications for the technology, major barriers were also 

identified, alerting experts to the need for additional tools to scrutinize these weaknesses. 

Post-Event Assessment 

58. Improved inspection techniques to assess damage to structures. 

59. Rapid determination of structure condition to determine residual stresses in structural 

members. 

60. There are very specific procedures that should be followed any time a tunnel is entered after 

an internal explosion. First, the air quality must be sampled to ensure that the tunnel is safe 

to enter without a breathing apparatus. If hazardous gas levels are still high in the tunnel, 

these must be used. Secondly, the tunnel must be inspected as it is entered for unstable 

structural damage that could result in injuries from falling debris (hardhats alone are not 

good enough). The Bureau of Mines has well-defined procedures for re-entries in the mining 

business. In the case of an explosion in a transportation tunnel, some minimal risks must be 

accepted in order to reach and rescue any people inside. It is expected that the Bureau of 

Mines guidelines would cover such rescue operations. Most fire departments should have 
34 

similar procedures for entering fire- or explosion-damaged buildings. Since the initial reentry will require the use of air quality monitors and other equipment, inexpensive handheld 

radiation detectors could easily be added if there is a suspicion that a dirty bomb might have 

been used. It is likely that those detonating a dirty bomb have the objective of getting the 

contaminants dispersed as widely and efficiently as possible and that structural damage is 

not their primary objective. Thus, the use of such a bomb to also damage a structure would 

probably be less likely. They would try to put it closer to population concentrations (e.g., 

downtown, etc.). 

Repair and Restoration 

61. Rapid repair of damaged structures. 

62. Decontamination of large-scale transportation infrastructure. In FHWA-led workshops on 

security, the difficulty of fully decontaminating large-scale transportation infrastructure 

arose repeatedly. This was particularly the case with radiological events, where it may not 

be possible to simply “wash off” surface contamination as would be done with chemical or 

biological hazards. This may also be a consideration in whether additional detection is 

necessary to protect bridges and tunnels. In the extreme, it might be necessary to replace (in 

part or whole) a bridge or tunnel structure that was structurally sound, but which could not 

be adequately decontaminated. This area needs to be fully explored. The most complex 

workshop decontamination scenario was a 32-centerline kilometer (20-centerline mile) 

section of interstate contaminated with a persistent chemical agent. The cost and scale of 

decontamination was astounding. The attendees could not figure out if the soil outside the 

shoulders would have to be removed (and replaced) in order to avoid recontamination of the 

roadway. Firefighters and hazardous materials specialists have never considered anything on 

this scale. 

63. Rapid replacement/repair: Uninterrupted traffic flow is the most important requirement, so 

we have to focus on the development of efficient procedures/methods (new materials, 

technology). 

64. Material performance. 

65. Additional knowledge and understanding is needed in the performance of different materials 

under different types and magnitudes of blasts. 

66. Development of guidelines for material selection to enhance bridge performance under blast 

conditions. 

67. Development of new technology to promote toughness in concrete materials (e.g., microand nano-fiber materials) that can inhibit crack propagation from dynamic loading and blast 

loadings. 

68. Determine the effects of radiation exposure on the structural properties of materials used to 

design our structures. 

69. The most promising area for improvement of bridge performance and longevity is new 

materials. We need new materials and more sophisticated electrical equipment for the future. 
35 

70. There is a need to know what are the pressures generated in blasts of ammonium nitrate, 

dynamite, nitroglycerin, etc., as a function of poundage and distance (radial pressure 

distribution), and the millisecond duration of such pressures. 

Evaluation and Training 

71. Integration of critical databases in a GIS format. 

72. Institute a Highway Innovative Technology Evaluation Center (HITEC)-type evaluation 

program for bridge and tunnel security. 

73. There could be a course on anti-terrorist measures given to bridge inspectors to specify the 

areas of vulnerability on a bridge-by-bridge basis. Immediate field action should follow, 

with a biennial repeat. 

Others 

74. There is a need to work with other agencies that have been involved with terrorism and the 

protection of military structures to transfer knowledge to civil structures. 

37 

APPENDIX B 

RECOMMENDATIONS OF THE BLUE RIBBON PANEL 

FOR BRIDGE AND TUNNEL SECURITY 

A Blue Ribbon Panel (BRP) of bridge and tunnel experts was convened to examine bridge and 

tunnel security. FHWA’s charge to the panel was to “develop short- and long-term strategies for 

improving the safety and security of the Nation’s bridges and tunnels, and to provide guidance to 

highway infrastructure owner/operators.” Its recommendations are recorded in report no. 

FHWA-IF-03-036, Recommendations for Bridge and Tunnel Security, September 2003.(2) The 

intent of the report is to “recommend policies and actions to reduce the probability of 

catastrophic structural damage that could result in substantial human casualties, economic losses, 

and social-political damage.” Toward this end, the BRP makes seven overarching 

recommendations in three areas: institutional, fiscal, and technical. The report, however, focuses 

more on the technical recommendations because of the charge that it was given and because of 

the collective strengths and expertise of the panelists. Summarized below, from the report, are 

the Overarching Recommendations, followed by more detailed recommendations for R&D that 

address the near- and long-term design and engineering solutions. 

OVERARCHING RECOMMENDATIONS 

Institutional Recommendations 

1. Interagency Coordination 

2. Outreach and Communication Strategies 

3. Clarification of Legal Responsibility 

Technical Recommendations 

4. Technical Expertise – Security solutions should be “engineered” and FHWA, as the Nation’s 

primary federal agency with the necessary engineering expertise, serve as the coordinating 

agency for prioritizing critical bridges and tunnels and administering program to allocate 

funds to responsible agencies to meet high priority security needs. 

5. Research, Development, and Implementation – Engineering standards do not exist regarding 

security concerns for bridges and tunnels. Technology should be developed and validated 

through appropriate R&D initiatives identified herein to address this need. 

Fiscal Recommendations 

6. New Funding Sources for Bridge/Tunnel Security. 

7. Funding Eligibility. 
38 

Research and Development Recommendations 

The BRP recommends R&D initiatives with a goal of creating “empirically validated 

computational tools, design methods and hardening technologies to assist in designing for the 

terrorist attack.” The recommendations with short- and long-term elements are directed to 

FHWA, AASHTO and other government-sponsored research activities, including universities 

and federal laboratories. 

1. Assess performance of critical elements under credible loads (including load reversals) 

Short-term (within the next year): 

• Synthesize current state of knowledge for component properties and modeling 

Long-term (more than one year): 

• Establish the load structure and load interaction 

• Start component experiments; recommend large-scale testing using real materials, 

components, and connections under comparable strain rates 

• Conduct comparative parameter studies of typical components and materials 

2. Validate and calibrate computational methods and modeling with experiments to better 

understand structural behavior from blast loads 

Short-term (within the next year): 

• Pull together and examine studies and research that have already been conducted on 

bridge and tunnel elements and components 

• Investigate transferability of seismic design 

Long-term (more than one year): 

• Develop a predictive round robin analysis of actual blast experiments on bridge and 

tunnel components 

• Test critical components, such as suspender ropes, stay cables, concrete and steel decks, 

side loads on towers, and box sections, for testing and blast performance 

3. Validate and calibrate computational methods and modeling with experiments to better 

understand structural behavior from thermal loads 

Short-term (within the next year): 

• Pull together and examine studies and research that have already been conducted on 

bridge and tunnel elements and components 

Long-term (more than one year): 

• Evaluate various mitigation fire effects in tunnels, double deck bridges, and overpass 

bridges 
39 

4. Determine the residual functionality of bridge and tunnel systems and their tolerance for

extreme damage 

Short-term (within the next year): 

• Examine bridges and tunnels compromised in wars and after demolition attempts 

Long-term (more than one year): 

• Determine progressive collapse potential of various bridge and tunnel systems 

5. Develop mitigation measures and hardening technologies 

Short-term (within the next year): 

• Assess existing hardening technologies and the applicability to bridges and tunnels 

Long-term (more than one year): 

• Develop new materials and new design methodologies 

In addition to these R&D recommendations, the BRP suggests AASHTO work with university 

engineering institutions to develop R&D programs for students and bridge professionals to 

address security concerns. The panel recommends that DHS work jointly with industry and state 

and local governments to explore and identify potential technology solutions and standards that 

will support analysis and afford better and more cost-effective protection against terrorism. 

41 

APPENDIX C 

RESULTS FROM THE SECURITY WORKSHOP 

The product of this workshop was an unstructured and unprioritized collection of gaps in 

knowledge, understanding, and technology. This represented the collective thinking of a group of 

knowledgeable and experienced professionals who have been directly engaged in improving the 

security of the Nation and its highway systems at the operational and policymaking level. 

Reducing the Vulnerability of the Nation’s Highway Systems 

1. Need for a better understanding of the interrelationship and interdependencies of the 

highway network and other systems. 

2. The sharing of sensitive information is perceived as a need that will prevent us from 

achieving our goal of improved security. 

3. Information, methods, and tools for prioritization are needed. 

4. Targets need to be identified. 

5. Network analysis is lacking. 

6. National network vulnerability analysis is lacking. 

7. Multi-objective optimization within a vulnerability and security framework is needed. 

8. Is it possible to do this by simply tying local networks together? 

9. The threat is unknown and hard to quantify in a probabilistic sense. Traditional risk 

assessment methods are hard to apply. 

10. Insider threats and crime also need to be considered. (We have not considered how to reduce 

the risk of highways being used to help commit crime.) 

11. Other critical infrastructure needs to be considered, such as transit. 

12. An explicit definition of what is critical infrastructure is needed. 

13. Can cargo tracking technology reduce risk? 

14. Cost-benefit analysis of vulnerability reduction. 

15. Model elements and test them. There is a need to verify models for testing. There are tools, 

but no clear models, so we need to verify models (cannot go off of computer assumption). 

16. Need to contribute to DHS Critical Infrastructure R&D Plan. 

17. Specific information on connection details is lacking (connection within a bridge, not the 

columns) (e.g., 100-year-old steel bridge). 

18. National strategy for spending not in place for security infrastructure. 
42 

19. Looking at other scenarios other than the common blast scenario (e.g., poison in cargo ship). 

Other threats need to be considered. 

20. Military standards are available as a tool, but are not necessary applicable to highway cases. 

21. There is a need for a National Strategy for spending for security. 

22. The assumption that a blast is the most likely threat must be challenged. 

23. Ask: What are realistic damage states for highway infrastructure? How much damage is 

tolerable? Where are we vulnerable? 

24. In an ideal world, know what is in the carrier (ship, truck). Cargo tracking technology is 

needed. 

25. Risk needs to be considered in the TSL stage. 

26. Low-cost changes to new structures need to be reviewed and included in overviews. 

27. National local networks need to be tied together. There is much information floating locally; 

there is no national tie-in to bring it all together. 

28. Security threats from inside agencies should be considered. 

29. Cost-benefit analysis is necessary. 

30. Risks to be considered in early part of design. 

31. Ticket checker example. System design for operations strategies. They need to be checked. 

How often do we check systems in place? Security checks? 

32. Fire suppression and analysis are necessary. 

33. Research the application of artificial intelligence or other adaptive computational methods 

and emerging technologies to this aspect of the problem. 

34. Information about threats: 

a. Intelligence ration: Getting information to the right people. 

35. Validation tools/models for analyzing dynamic failure (blasts, impacts). 

36. Probability risk assessment methodology: 

a. Ranking critical infrastructure (assessing it). 

b. Distribution of funds. 

c. Strategies to reduce risk. 

37. Physical vulnerability vs. operational vulnerability. 

38. Operational vulnerability: 

a. Power grid systems (cause and effect). 

39. Design guides/specifications: Ultimate goal is cost-effective measures. 

40. Creating a tool to make it more cost-effective. 

41. Cost-effective advanced materials (nanotechnology) design solutions. 
43 

42. Integrated software tools (integrating different modules for better decisionmaking). 

43. Alternative power source (off grid for traffic control purposes). 

44. Handling sensitive security information: 

a. Getting it to the right person. 

b. Plans and designs as examples of this information (whether available or not). 

c. Computation/modeling. 

d. Goal: Developmental work protected, but final product is open. 

e. Legislative involvement and impact on changes. 

f. Final product and availability. 

45. Biological/radiological sensors. 

46. Improve surveillance and monitoring capabilities. 

47. Transportation issues: 

a. Broaden our focus. 

b. Transportation funding over model funding. 

48. Guidance to be included on the Web (e.g., hazardous materials sites, nuclear sites, bridge 

locations, defense routes). 

49. Is there sufficient knowledge of surge capacity? 

50. Smart structures: Can these reduce vulnerability? 

51. Rapid post-event assessment methodology in place. 

52. Need literature search on what others have done. 

53. What are the cross-cutting issues (risk-reduction metrics)?: 

a. Threat, vulnerability, risk assessment, countermeasures against security (risk-reduction 

metrics). 

b. Interdependencies for infrastructure. 

c. Redundancy (alternative routing/intermodal): 

i. Other options. 

ii. Redundancy reduces criticality and attractiveness. 

d. Collaboration, communications, coordination (i.e., intelligence). 

e. Interoperability. 

f. Analytical tool required. 

g. Security cost tradeoffs (e.g., potholes vs. security). 
44 

54. Detection: 

a. Intrusion detection. 

b. Cameras – semi-automated analytical tools to reduce FTE. 

c. Cheap, easy-to-use alternative to current video systems. 

d. Biological/radiation/chemical detection – detect at high speeds. 

e. Institutionalized arrangements for response. 

f. Analytical support tools – synthesizing systems. 

g. Create a system that is not highly dependent on electrical sources. 

h. Broad category of sensing. 

i. Synthesis of existing technology and practices. 

j. Communications between these remote sensors. 

55. Deterrence: 

a. Effectiveness of surveillance on deterrence. 

b. Strategies to reduce target value. 

c. Coordination of security risk vis-a-vis other societal values. 

d. Scientific risk – society tools (how much to invest on security). 

e. Effectiveness of physical patterns on deterrence. 

56. Defend: 

a. Vulnerabilities: 

i. Suspension bridge towers. 

ii. Bridge cables. 

iii. Through arches. 

iv. Box girders. 

v. Thin-shell underwater tunnels. 

b. Need to identify mitigation strategies and testing methodologies for above. 

c. Materials for defending: 

i. Column wrap. 

ii. High-performance material- fiber reinforced concrete. 

iii. Thermal protection. 

iv. Windows – electromagnetic pulse. 

d. Barrier Effectiveness. 

e. Biological/chemical strategies and technologies. 
45 

57. Deny: 

a. Methods to achieve standoff/enforcement (what works for enforcement). 

b. Routing restrictions (access or deny in critical infrastructure). 

c. Strategies to deny access to critical infrastructure. 

d. Parking restrictions (how effective are they?) – inspect, proximity to critical 

infrastructure and elements. 

Reducing the Risk of a Highway System Being Used as a Means to Attack 

1. Sensors to detect threat (unauthorized vehicle or cargo). 

2. Integration of sensors into a system to detect a threat and perhaps respond. 

3. Include institutional process. 

4. Technology to deal with data overload. 

5. Boiling it down to a green light (data mining). 

6. Chain-of-possession system (identify the possessor of freight). 

7. Process to share intelligence and data (tied to communications interoperability). 

8. Simulation tools to develop and evaluate the above. 

9. Testing of actual systems using simulated attack (exercise or drill) at a large scale at the 

multi-agency level. 

10. Sensitivity analysis of frequency of test and exercise. 

11. National tracking system: 

a. Integration of State (local) systems at the national level. 

b. Effects of such systems on mobility or congestion. 

12. Mobility can spread a biological or radiological agent. 

13. Deterrence, or denial of access, if a threat is detected through intelligence (pre-screening). 

14. Lack of knowledge of threat. Access to intelligence. 

15. Highway ISAC (design and capability analysis). 

16. Research on deterrence. 

17. Development of new sensors: 

a. PPB sensitivity is here. 

b. MEMS is here. 

18. Strategy for deployment of sensors. 

19. Reliability of detection studies. 

20. Detecting and responding to behavior patterns (pattern recognition). 

21. Research on the security benefits of law enforcement (presence and visibility). 
46 

22. Other applications of the benefits of this technology for other law enforcement areas. 

23. What will public tolerate with regard to infringement on personal liberty? 

24. Balance with legitimate movement of explosion, radiation, etc. 

25. Legal research into what is our authority to do such things. 

26. Tie to permitting systems. 

27. Must be coordinated with DHS. 

28. Link to intelligence systems. 

29. Detect changes in drivers. 

30. Technology transfer from other industries that may have better ways of dealing with this. 

31. Scalable to the national level. 

32. Decision support systems for making investments technologies vs. benefits vs. risk. 

33. Fitness for duty (dual benefit). 

34. Eyes-on-the-road program – dealing with the data. 

35. Reliability of detection study. 

36. Linkage to law enforcement system is essential. 

37. Research on efficiency and management of a HISAC 

38. Proper archiving of data: 

a. Data aspects of the problem. 

b. Data management for security. 

39. Coordination with other systems (e.g., Amber Alert). 

40. Design of highway to reduce use as a weapon. 

41. All aspects need to be considered. 

42. Use traffic control systems to thwart an attack. 

43. Consider the business interests as well. 

44. Possible use of TRANSIMS 

45. Need to better understand how the highway system can be used to deliver an attack. 

46. Research of targets. 

47. Data communications: 

a. Protection at data transmission. 

b. Any control systems. 

48. Tracking cargo: 

a. Origin to destination. 

b. Screening for weapons of mass destruction. 
47 

49. Route restriction. 

50. Managing the flow of hazardous cargo: 

a. Developing analytical tools. 

b. Evaluate the impact of strategies. 

51. Developing better screening techniques. 

52. Using technology to identify suspiciously operated vehicles. 

53. Advanced screening/surveillance. 

54. Identifying overheight/overweight vehicles. 

55. Establishing rings of security to detect threats. 

56. Enabling DOT employees to be more alert (training): 

a. Research to determine the characteristics and attributes of suspicious vehicles/drivers. 

57. Identifying human factors research (associated with security aspects/actions in 

chemical/biological/nuclear/radiological event): 

a. Management. 

b. Employees sent to establish quarantine barriers (looking at other agencies to support). 

58. Using bridges as platforms for delivery (study to evaluate citing and design). 

59. Research to identify critical node points in our transportation network. 

60. Research to provide redundant transportation systems for critical node points. 

61. Freight security (applications to borders and tunnels): 

a. Cargo tracking. 

b. Cargo identification. 

c. Anti-hijacking technology (public fleets and private fleets). 

d. Hazardous materials routing. 

e. Vehicle tracking. 

62. Traffic surveillance: 

a. Non-typical behavior recognition. 

b. Driver licensing. 

c. Route deviation alerts. 

d. Rapid response techniques. 

e. Remote sensing and tracking (chemical, radiation, biological). 

f. Evaluation of technical solutions and cost. 

63. Response and control methodologies. 

64. Calibration (resolution of false indications). 
48 

65. Threat definition: 

a. What are we designing to prevent? 

66. Physical security: 

a. Barrier design guides. 

b. Barrier usage/applications. 

c. Vehicle inspection (visual, sensing). 

d. Routing options (vehicle restrictions). 

e. Rapid threat investigation technology. 

f. Vehicle restrictions. 

g. Access denial. 

h. Rapid removal of vehicles. 

67. Evaluation of hardening vs. policing. 

68. Tunnel ventilation control and detection systems. 

69. Surveillance: 

a. Effectiveness of highway watch. 

b. Terrorist screening of driver’s license applications. 

70. TWIC requirements at key construction sites/critical factors. 

71. Alternatives to standard national security clearance procedure. 

Improving the Utility of the Highway Systems to Respond to and Recover From an Attack 

1. Role of transportation in a biohazard situation? Traffic control paradigm? 

2. Linkage to modeling and simulation. 

3. Modeling in advance of an incident. 

4. Real-time modeling capability. 

5. Decontamination: How to do it? (biological and radiological). 

6. Decontaminate vehicles? 

7. Exploration of how intelligent transportation systems (ITS) get applied in response and 

recovery. 

8. Capacity of system under extreme situations (emergencies). Reverse directions, etc. 

9. Basic highway engineering questions. 

10. Linkage to other infrastructure systems (e.g., cell phone systems): How do we do it? 

11. Role playing/people simulation: How bad does a situation have to be before an emergency 

declaration is made? What types of decisions are people willing to make? 

12. What other infrastructures could take down the transportation system (e.g., electric grid)? 
49 

13. Develop studies on how long it would take to evacuate a city: Evacuation modeling is a gap. 

Basic behavior information is missing. Some behavior is counterintuitive. Some behavior is 

contrary to governmental guidance. 

14. Taken off of modeling of hurricane evacuations. 

15. Dealing with an unplanned evacuation. 

16. Pass through in medians (guidance, number, etc.) break the barriers. 

17. Understanding what is involved in decontamination. 

18. Research into materials that are more tolerant of decontamination. 

19. Effective communication with people in vehicles. 

20. Basic research in disaster communication. 

21. Dealing with pedestrians in an emergency situation. 

22. Focus on moving people not just vehicles (linkage to other modes). 

23. Traffic officers might not be available. 

24. Assumptions need to be changed. 

25. Public awareness of routes (public education/preparedness). 

26. Optimal decisionmaking tools: 

a. War games. 

b. Simulation. 

c. Lines of authority (changes in laws needed?) – Federal/State/local. 

27. Specific roles/responsibility/authority defined and refined through simulation (role playing). 

28. Research into rapid recovery, repair, etc. 

29. Sensors for real-time analysis and decisionmaking (is the bridge safe to use or not?). 

30. Possible need to understand military mobilization needs in today’s world. 

31. Dealing with emergencies in rural areas. 

32. Modeling of the national system lead – interdependency again 

33. Research needs to include deployment plan considering the capability of users. Need to train 

potential users. 

34. Identify capabilities needed to respond and use tool. 

35. Ultimate effects/constraints to response and recovery. 

36. Rapid recovery of ITS infrastructure. 

37. Standards for redundancy and reliability of ITS/traffic control systems. Possible implications 

for design. Back in service in a short time. 

38. Standards for systems redundancy (possible implications for design). 

39. Dual use must be a basic guiding principle. 
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40. Include response and recovery to routine events. 

41. Research of technology in support of National Incident Management System. 

42. Identification processes for key personnel to enter an area in the event of an attack. 

43. Clearly developed policy and implementation guidelines for agencies in the event of an 

attack for tool development. 

44. Communication interoperability (SAFECOM): 

a. Voice and data communications, standards, and architecture between effective parties as 

needed for security event. 

45. Identification of alternative routes: 

a. Enhancement of the Strategic Highway Network (STRAHNET). 

46. An all-hazards approach in dealing with security issues. 

47. Forensics experts (national pool). 

48. Quick analysis needed to avert other attacks. 

49. Identification of organization to develop tools, use the developed tools, conduct analysis, 

and provide results. 

50. Develop alternative evacuation strategies and plans: 

a. Local. 

b. Regional. 

51. Post-event assessment (consistent data-gathering protocol lessons learned). 

52. Response planning for an event. 

53. Rapid recovery (e.g., rapid replacement of structures (short-term, long-term)). 

54. Enhanced traffic monitoring network. 

55. Alternative power supply.

56. Evacuation rerouting techniques: 

a. Reversible lanes. 

b. Movable traffic barriers. 

57. Medical evacuation planning. 

58. Identification and isolation of the hazard. 

59. Planning for multiple attacks. 

60. Regional coordination through multi-jurisdictional areas. 

61. Rapid assessment. 

62. Improvement of system use in response and recovery: 

a. Need for rapid repair options materials. 
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b. Maximizing short-term lane. 

c. Emergency lane clearance. 

d. Proper amount of system redundancy. 

e. Communications (what?, to whom?). 

63. Response planning: 

a. Human factors in emergency situations: What can you expect? 

b. Ability of current network tools to model human behavior under stress. 

c. User needs assessment during emergencies (do current models reflect the needs?). 

d. What are the data needs for modeling response options? 

64. Chemical/biological/radiation cleanup: 

a. Structural capacity of damaged critical infrastructure. 

b. Tools to access roadway incidents in terms of security implications. 

c. Response strategies for DOT employees. 

d. Literature search on response to natural disasters and an evaluation of the implications for 

response preparedness for State and local DOTs. 

65. International border implications regarding emergency response and recovery at borders: 

a. Jurisdictional issues. 

b. Federal roles in developing possible plans. 

66. National incident command systems as a requirement for DOT. 

67. Coordination of the transportation requirements of special response teams (urban search and 

rescue) (management training) under national response plan (interdependency). 

68. Special structural load-carrying capabilities (analytical techniques). 

69. Communications procedures. 

70. Legal agreements. 

71. Secure communications needs and systems for use in emergency situations. (FederalFederal, Federal-State, State-State, etc.).

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REFERENCES 

1. Office of Science and Technology Policy, Executive Office of the President, and the Science 

and Technology Directorate, Department of Homeland Security, The National Plan for 

Research and Development in Support of Critical Infrastructure Protection, 

Washington, DC, 2004. 

2. Federal Highway Administration, Recommendations for Bridge and Tunnel Security, Blue 

Ribbon Panel Report, Report No. FHWA-IF-03-036, Washington, DC, September 2003.