Roles and Implications of Transportation Systems in Homeland
Security
David Ekern, PE – Commissioner
Virginia Department of Transportation, Virginia, USA
Joe Crossett, Partner
High Street Consulting Group, Pennsylvania, USA
Abstract
State departments of transportation are responsible for planning, delivering, operating, and
maintaining a vast surface transportation network that Americans depend on for safe, predictable,
and easy movement of people and goods. The apparent scale and redundancy of the nation’s
transportation network gives a false sense of security, as in many parts of the country that
network is straining to keep up with the transportation demands of society and the economy. A
single unexpected interruption in one location may have a dramatic ripple effect on ease and
reliability of travel across a wide region. This paper discusses the emergency preparedness
capabilities that public-sector transportation agencies are acquiring as their awareness grows
about threats to safe and efficient operation of the nation’s transportation network. It covers the
organizational elements and planning approaches critical to developing effective all-hazards
emergency preparedness capabilities and it examines the roles that transportation agencies are
developing to help prevent, prepare for, respond to and recover from serious incidents.
In the United States, state departments of transportation (DOTs), working with
agencies at the local and federal governmental levels, have responsibility for
planning, delivering, operating, and maintaining a vast surface transportation
network that includes not only four million miles of roads serving local, regional
and national travel needs [1], but many rail lines, bus and rail transit systems,
ferries, ports and waterways. The emergency preparedness capabilities that
public-sector transportation agencies are acquiring are critical to safe and
efficient operation of the nation’s transportation network in the 21st Century.
Whether moving by car, truck, bus, train, ferry or on foot, Americans depend on
surface transportation for safe and predictable mobility. On trips through town or
across the country, vehicles drive an estimated eight billion miles on roads in the
United States every day [2] and a considerable share of daily travel is associated
with moving the estimated 89 percent of all freight by value that is shipped on
highways [3].
The apparent scale and redundancy of the nation’s transportation network gives
a false sense of security, but in many parts of the country that network is
straining to keep up with the transportation demands of society and the economy.
A single unexpected interruption in one location may have a dramatic ripple
effect on travel across a wide region.
In August 2007, for example, the collapse of Minnesota’s busiest bridge (I-35W)
that carried 140,000 vehicles a day over the Mississippi River between downtown
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Minneapolis and its northern suburbs, not only caused tragic loss of life but is
expected to have an economic impact of about $60 million in road user detour
costs incurred before it is fully replaced [4] at an expected to cost of at least $393
million. The US Department of Transportation estimates there are at least 1,000
bridges across the country where substantial casualties and economic disruption
would result from isolated terrorist attacks [5].
Homeland security is one among many threats to safe and efficient operation of
the nation’s transportation network. An act of terrorism at a busy bottleneck or
malevolent destruction of a major bridge would almost certainly cause
unacceptable loss of life and temporary disruption of economic stability and
necessitate costly infrastructure repairs. Historically a range of threats such as
floods, earthquakes, extreme weather, wildfires, or major traffic incidents have all
proven capable of generating similarly adverse outcomes.
As travel grows with economic prosperity, lower density land use, and more
mobile populations, incidents of any kind pose greater potential to disrupt the
transportation network. Transportation agencies have no choice but to enhance
their emergency preparedness capabilities to ensure they can meet five
fundamental responsibilities:
1. Prevent incidents within their control and responsibility;
2. Protect transportation users, agency personnel and critical infrastructure;
3. Support regional, state, and local emergency responders with resources
including facilities, equipment, and personnel;
4. Recover swiftly from incidents; and
5. Evaluate response(s) and continually improve plans, training, skills and
protocols.
Meeting these responsibilities requires the engagement of skilled employees in a
transportation agency, leadership by senior executives, and critical targeted
investment in technology, people, and infrastructure.
Fortunately, transportation agencies can build from a strong foundation as they
enhance their emergency preparedness capabilities. This is because successful
prevention, protection, response and recovery from terrorist attacks depends on
many of the same technologies, staff skills and organizational structures needed
to handle other threats. As a consequence, many transportation agencies,
including over 90 percent of state DOTs, have in place all-hazards emergency
preparedness plans that enable them to respond to serious incidents regardless
of their cause [6].
No two transportation agencies share exactly the same characteristics and onesize-fits-all fixes are not the solution for stronger homeland security, but some
common themes are emerging that merit further scrutiny. The organizational
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elements and planning approaches critical to developing effective all-hazards
emergency preparedness capabilities and the roles that transportation agencies
are expected to perform in preventing, preparing for, responding to and
recovering from serious incidents.
Organizational Elements of Preparedness
A transportation agency’s organizational structure is the framework that allows it
to establish successful all-hazards emergency preparedness capabilities. The
agency must be willing to blend new all-hazards functions with traditional
organizational elements. Transportation agencies with strong all-hazards
emergency management programs exhibit the following organizational elements
[7].
A high-level all-hazards manager
State DOTs are recognizing that all-hazards preparedness cannot be achieved
without a full time, senior-level manager who is the agency’s focal point for
building and maintaining its all-hazards management capabilities. Many allhazards preparedness activities involve sharing ideas among traditional
transportation disciplines such as traffic operations, maintenance, engineering,
and construction, so the all hazards manager in a transportation agency must
have a broad understanding of many disciplines, from traffic operations and
highway maintenance to information technology or bridge and tunnel design. The
all-hazards emergency manager must be in close communication with executive
staff so that critical issues before, during, and after incidents can be quickly
raised to the highest levels, as needed. Many state DOTs have learned that colocation of all hazards emergency management with their maintenance and
operations functions makes sense because this is where the greatest overlap
occurs among field staff awareness, emergency traffic operations, and other
direct service activities. This becomes an even stronger function when colocation can be integrated with public safety agencies.
All-hazards leadership team
The all-hazards manager should form and lead an inter-disciplinary team that
brings together key agency personnel from disciplines such as maintenance,
traffic operations, planning, design, and construction on a regular schedule. The
functions of the team should include regular review of emergency incident
reports, trends, program audit findings; and preparation of recommendations to
senior management on changes emergency preparedness plans and processes.
All-hazards technical specialist staff
Depending on factors such as the size of the agency, existing staff capabilities,
and criticality of risks, one or more additional staff are needed to support the allhazards manager. Core focus areas of experienced specialist(s) include
responsibility for training, exercises, evacuations, technology, and intelligence. In
large state DOTs, the headquarters all-hazards and security team must have
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close links to districts that act for the DOT on the frontline during incidents. Each
DOT district must have an experienced professional whose responsibilities
include all-hazards emergency preparedness.
External partnerships
Organizational exchange must be strengthened between transportation agencies
and partners such as emergency management agencies, the first responder
community, law enforcement, public health, and intelligence. An effective allhazards manager must be active in a wide variety of state and federal networks
for addressing emergency management issues. These connections promote
sharing of ideas and information among disciplines and agencies that can greatly
enhance a DOT’s all-hazards preparedness program.
All-Hazards Emergency Preparedness Plans
Transportation agencies’ all-hazards emergency preparedness plans are vital to
prevention, protection, response and recovery from emergencies of all kinds.
They enable every employee to understand their responsibilities; they help
leadership hold staff accountable; and they allow the agency to work effectively
with other organizations. Exemplary transportation agencies stand out because
they have concentrated on integrating their plans into a single plan document.
Their plans feature the following elements [8].
Consistency with national emergency planning principles
The National Incident Management System (NIMS), Incident Command Structure
(ICS) and National Response Plan (NRP) are initiatives headed up by the US
Department of Homeland Security and they are the standard for emergency
management planning. Many transportation agencies have built their emergency
preparedness plans around NIMS, ICS and the NRP.
A single emergency preparedness plan
A transportation agency’s emergency preparedness plan must be an overarching
document that is adopted by senior leadership and is the day-to-day resource
within the agency for describing all general incident management planning,
emergency operations center activation, and command and control and
communications architecture that are applicable to incidents.
Hazard Type annexes
Hazard annexes can be attached to the primary emergency preparedness plan
that provide details about threat-specific roles and responsibilities for addressing
specific hazards such as terrorism, bio-chemical, nuclear, fire, tornado,
earthquake, snowstorm, or flood emergencies. Likewise, an annex can be
included for continuity of operations planning that describes how the agency will
continue to operate if a disaster impacts key infrastructure or critical assets.
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Distribution and regular updating
Appropriate staff must have ready access to the latest version of the emergency
preparedness plan. Furthermore, the plan and its annexes must be treated as a
living document that is adapted as changes in the local operating environment
and global situation dictate. The cycle for conducting a comprehensive update of
the plan could be as frequent as once a year, but should certainly occur at least
once every two years.
Incident Prevention Capabilities
Terrorist attacks differ from natural and accidental disasters because they are
intentionally perpetrated acts that could possibly be prevented or deterred. The
heightened threat of terrorism has led transportation agencies to pay much closer
attention to counter measures for preventing malevolent attacks against assets.
State and federal transportation agencies are working together with researchers
to use seismically safe technologies and knowledge to enhance the blast
resilience of their transportation structures. Blasts, such as those caused by a
truck bomb parked near a bridge for example, have very similar structural effects
to those that take place in an earthquake. Some of the tools and techniques
developed over the past 25 years to make structures seismically safe may be
used to make structures more resistant to terrorist attacks. These include use of
redundant structural systems that are designed to reduce the risk of catastrophic
collapse by transferring loads supported by lost or damaged columns to columns
still intact, and structural dampers that are designed to absorb and reduce
damaging vibrations.
The cost of installing countermeasures for even a handful of transportation
infrastructure assets is high. Much of the transportation system is characterized
by features such as physical robustness, system redundancy and limited
potential for mass casualties that make it a relatively unappealing terrorist target.
By contrast, specific transportation facilities, such as those that span large
natural barriers such as rivers, bays or mountains, and serve unique regional or
national transportation and economic roles, may be attractive targets. Key
transportation agency prevention capabilities should include the following
elements.
Risk management
Risk assessment or vulnerability assessment involves considering the probability
of an event and its likely consequences on people and assets. Transportation
agencies are constantly refining risk management techniques to identify and
protect high risk assets such as multi-tier bridges, overpasses that traverse
navigable waters, flammable pipeline crossings, tunnels, heavily congested truck
routes, and roadways adjacent to other targets. Armed with accurate information
about risks, transportation agencies can identify and implement cost-effective
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countermeasures to reduce risks to transportation assets, including risks from
natural disasters and from sources of intentional harm such as terrorism.
Deterrence and detection improvements
Transportation agencies are putting in place a variety of deterrent and detection
measures for better protecting critical facilities and assets. These measures work
by creating a greater likelihood that potential aggressors will be caught and may
even be deterred from attacking an asset. The effectiveness of deterrence varies
with the aggressor’s sophistication, the asset’s attractiveness, and the
aggressor’s objective.
Measures undertaken by transportation agencies include installation of fences to
increase stand-off distances from vulnerable structural components such as
bridge piers or tunnel ventilation systems; secure access to structures; better
lighting; electronic detection systems; elimination of parking areas beneath
structures; security patrols and cameras; use of identification badges for
employees and visitors; and background investigations on employees and
contractors with access to critical information and facilities.
Infrastructure hardening
As facilities are added or renovated on the transportation network and old
structures are replaced or rehabilitated, transportation agencies must take
advantage of opportunities to incorporate more advanced design features for
critical infrastructure assets that make them more resilient to attacks, such as
location and design considerations, pier placement, and blast survivability.
Public awareness building
Transportation agencies are using communication tools such as rest stop
information centers, highway variable message signs and congestion reporting
websites to implement high visibility emergency awareness programs for the
public that emphasize the importance of vigilance and provide clear direction on
reporting of suspicious activities.
Information sharing
Transportation agencies must regularly participate in a variety of forums for
sharing threat and intelligence information including networks or arrangements
with state and local emergency management, law enforcement and homeland
security officials.
Control of sensitive information
Transportation agencies must take steps to control access to documents that
contain sensitive information about security critical systems and facilities. Steps
that include creation of an oversight committee for setting sensitive information
policies; development of protocols to cover handling of access to documents,
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marking documents, storing documents, and requests for documents;
establishment of a single point of contact for managing sensitive information;
identification and protection of documents such as vulnerability or risk
assessments, emergency response plans and other documents on security
critical systems; and education of staff about sensitive information handling
protocols.
Incident Preparedness Capabilities
Transportation agencies do not lead emergency preparedness, response, and
recovery efforts, but they can and do play a vital support role to first responder,
public safety, and law enforcement partners.
Because they do not have high visibility roles, transportation agencies are
perceived by others as public works agencies with limited support capabilities.
Public safety and emergency management agencies, meanwhile, may not
understand how to assess an emergency situation in terms of its likely impacts
on the transportation system. Technical resources – such as advanced
surveillance systems possessed by state DOTs – are not well known to the
public safety community and are underutilized.
All-hazards preparedness means that transportation agencies are ready to work
with emergency responders whenever an incident occurs. When incidents
directly affect the transportation network, DOT field personnel must become first
responders so preparedness is critical. Preparatory actions enable a
transportation agency to anticipate and minimize the impacts of incidents via
advance planning. Many preparatory actions are relevant regardless of threat
type. Key preparatory capabilities often include the following elements.
Employee training
Training ensures transportation agency employees are educated about their
emergency management roles, responsibilities, and duties and ensures
proficiency in their performance. Establishing all-hazards training programs that
are consistent with Department of Homeland Security, Federal Emergency
Management Agency and Transportation Security Administration curriculums to
provide training to all employees in security awareness, emergency response
and critical infrastructure protection. Advanced training programs must be
provided for managers including CEOs, senior staff, maintenance operations
managers, and all-hazards managers.
Drills and exercises
Transportation agencies should conduct their own tabletop and functional drills at
least every three to six months to exercise emergency management plans and
participate as active players in full-scale exercises held at least annually. They
must use drills and exercises to develop follow-up actions including de-briefings
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and updates to plans, protocols and processes to incorporate after-action
findings.
Enhanced traffic management centers
Many DOTs are developing and expanding sophisticated “intelligent
transportation systems” that use electronic technology such as traffic cameras,
ramp monitoring, roadway sensors and message signs to monitor and manage
traffic in urban areas. Transportation agencies are upgrading their transportation
management center (TMC) capabilities from passive information collection to
fusing multiple sources of data that are capable of supporting on-scene
responders and the general public during incidents. These changes involve “247” operational requirements; access to special agency information systems, and
should require the TMC to evolve into an auxiliary Emergency Operations
Center, closely networked with other emergency responding agencies and
centers. As we move deeper into the 21st Century, co-location of transportation
management centers, emergency operations centers and public safety
answering points will become a critical security and economic necessity.
Emergency traffic operations
Transportation agencies must establish procedures for working with state and
local emergency responders to provide emergency traffic operations during an
incident. This should include determining how to assign equipment such as
mobile signs, trailblazer detour signs and barriers as well as development of
procedures for use of DOT maintenance and safety patrol personnel in assisting
police in road closures and traffic management in major emergencies when
police resources are stretched thin.
Evacuation planning
Transportation agencies must work with personnel from city, and county,
transportation, police, fire, and emergency management agencies, metropolitan
planning organizations and major hospitals to develop plans for primary and
alternative evacuation routes for major population centers. This work usually
includes identification of pre-planned detour routes for the Interstate highway
system and major thoroughfares, maps of each major highway access point
showing where emergency vehicles should be parked to block traffic, permanent
ramp gates at critical interstate entrances, assistance in preparation of major
metropolitan areas and downtown evacuation plans.
Communications interoperability
Transportation agencies must participate in communications interoperability
initiatives with first responders who have security responsibilities. This includes
multiple means for disseminating emergency notifications, including web
distribution, blast fax systems, radio codes, paging, and telephone calling lists, as
well as development of an integrated communications system and establishment
of mobile emergency response command centers to support various radio
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frequencies, including those for state DOT state patrol, and local police and fire
departments.
Equipment, facility and personnel inventory management
Transportation agencies are developing geographic information system-based
databases for tracking their emergency response resources including specific
equipment and its location, and personnel and their home addresses. This
enables managers to quickly pinpoint the closest available resources to
emergency or incident sites. The systems are often accessible via laptop
computer to supervisors in the field. Critical vehicles are equipped with automatic
vehicle location transponders to enable rapid location of vehicles during
emergencies and appropriate personnel such as motorist assistance patrols and
state patrol officers should be equipped with respirator masks or place gas
masks.
Incident Response and Recovery Capabilities
Transportation agencies have maintenance forces and equipment active across
the transportation network. As a result, they can play key response and recovery
roles during and after an incident. For example, on a weekday in July 2001 just
before rush hour in Baltimore, a CSX freight train derailed and caught fire in a rail
tunnel directly beneath the downtown’s central business district. By 4:30 p.m. the
City Fire Department had ordered all major roads into the city closed including
several Interstate routes. Maryland DOT’s modal agencies played vital roles
throughout the tunnel fire in maintaining traffic flow. The Coordinated Highways
Action Response Team (CHART) posted notices on variable message signs
advising motorists on closure of major routes into the city. State toll authority
personnel coordinated temporary closure of I-395 into Baltimore. The state’s
transit operators coordinated light rail, bus and commuter rail operations.
As the story of a major incident begins to leave the headlines, recovery efforts
are just starting, particularly when infrastructure damage is severe. If
transportation facilities are targeted or they experience ancillary damage, a stiff
economic toll may be exerted if they are closed to traffic, particularly when
alternate routes are not readily available. In such instances, pressure to rebuild
quickly is often intense. Transportation agencies are equipped to oversee
hundreds of infrastructure construction projects every year. Their access to
heavy equipment and contracting capabilities make them uniquely qualified to
lead reconstruction efforts.
The Los Angeles earthquake generated a year’s worth of reconstruction work in
a single event. The dramatic roadway damage caused by the earthquake placed
a significant strain on auto-dependent southern California. Bridges and roads
were completely knocked out at four locations on several Interstate and state
highways. CALTRANS, the state’s DOT, however, had its first emergency debris
and demolition contracts in place by 7:00 a.m. that day. CALTRANS
maintenance crews implemented initial detours, while commuter rail and bus
service was expanded to provide transportation alternatives. CALTRANS
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Highway Advisory Radio, Variable Message Signs, CCTV, speed monitoring loop
detectors, and traffic signal timing capabilities helped keep traffic moving in the
days and weeks after the earthquake. Subsequent recovery efforts involved
round-the-clock operations to accelerate reconstruction of earthquake resistant
structures. CALTRANS’ Traffic Management Center served as the center for
mobility decision-making throughout the recovery.
Capabilities developed by transportation agencies to support responders during
an incident and return to normal include.
Mobilization of equipment, people and private sector resources
Mobilization of emergency transportation operations by transportation agencies
and their partners involves assembling and organizing resources, including
people, equipment, communications systems, expert technical support, and
public information systems and protocols. It is a capability that requires that the
right people will deploy appropriate resources at the correct time.
Effective mobilization requires a partnership of local, regional, state, and federal
agencies. Joint preparedness training is important, while during response and
recovery voice and data communications must be interoperable, and information
must be shared. Key roles for transportation agencies include:

Dispatch of personnel to incident scenes including specialized service patrols
and incident response teams to help secure the incident scene; provide
emergency medical aid; support fire, rescue and emergency medical services
in their operations; relocate or remove vehicles and debris from the roadway;
assist stranded motorists and others on the roadway; provide for emergency
traffic control; and initiate longer-term traffic control for approaching traffic and
affected areas.

Arranging emergency contracts to engage specialty towing and recovery
services or special clearance equipment in a timely manner and to minimize
responder risk and traffic disruption.

Assessment of transportation infrastructure condition and closure of unsafe
components.

Transportation of equipment, personnel, and supplies for supporting
emergency activities, and provision of any highway clearances and waivers
needed to speed up such movements.

Provision of transportation-related resources such as vehicle repair facilities,
fleet parking, and storage areas to be used for servicing, refueling, parking,
and storage of emergency vehicles.

Provision of general traffic management assistance including posting of
temporary signing, portable variable message signs, temporary traffic
controls, one-way systems, barricades, detour routings, lowering of freeway
speed limits through use of dynamic message signs or variable speed limit
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signs, modification of ramp metering rates or signal timing to slow the flow of
traffic, use of flashing beacons and Highway Advisory Radio to issue public
warnings and advisories, and provision of vehicular traffic flow data and
information from permanent and temporary monitoring sites.

Use of traffic management centers operated by DOTs in many larger cities
that offer electronic technology such as traffic cameras, ramp monitoring, and
roadway sensors, to monitor and manage traffic.

Design and implementation of alternate transportation services to temporarily
replace capacity lost to disaster damage.

Provision of information for the public about issues such as road closures,
infrastructure damage, debris removal, and restoration activities via contacts
with radio, television and other commercial media and use of technologies
such as highway advisory radio, 511 travel information, variable message
signs, and Internet web pages.
Recovery of Transportation Infrastructure
As emergency management activities switch from response to recovery,
transportation agencies play either a key supporting role or a leading role if
transportation facilities have been damaged. Recovery of transportation
infrastructure helps communities reestablish economic and social vitality. Key
roles for transportation agencies include:

Deployment of trained and skilled teams for rapid clean up, repair and
inspection of incident areas.

Restoration of critical transportation routes and facilities, via deployment of
emergency contracting procedures for restoration of transportation assets,
services and systems.

Issuance or waiver of permits and other assistance required to restore utility
lines or pipes that are immediately adjacent to, or run over or under
transportation infrastructure.

Continuing to keep travelers informed about important information on road
closures, detours, and evacuation routes to travelers.

Assistance with site investigation procedures including crime scene
preservation and documentation, use of data collection technology and team
procedures to minimize disruptions to traffic and responder exposure on
roadways.

Documentation of expenses used in cleanup or incident management for
possible reimbursement by FEMA or other entity.

Establish an employee assistance program and mental health services for
responders which includes professional counseling and peer discussion
groups.
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
Audits of entire incident response after each event and revisions to plans and
procedures as necessary to improve the key activities of prevention,
preparation, response and recovery in the future.
Conclusions
The costs of failure to prepare for a terrorist attack that affects the nation’s
transportation infrastructure, in terms of loss of life and economic disruption,
could be catastrophic. Transportation agencies were able to act swiftly on
September 11, 2001 and in other major incidents because they were already
equipped to meet the challenges of responding to and recovering from the
devastation caused by natural and man-made disasters. When incidents such as
hurricanes, wildfires, earthquakes, snowstorms or major traffic crashes threaten
safety and mobility, transportation agency personnel and equipment are part of
response and recovery activities. Their sophisticated traffic management
systems helps keep traffic moving, their information systems help keep
communications flowing, and their construction expertise helps speed recovery.
The threat of terrorism, however, poses new challenges for transportation
agencies. Because eighty percent of state DOTs report they have incurred
additional costs to improve transportation security, continual investment in
training, equipment, infrastructure hardening, and research for transportation
agencies is vital.
References
[1] Federal Highway Administration, Highway Statistics 2005, US Department of
Transportation, Washington, DC, 2007
[2] Ibid
[3] Parsons Brinkerhoff, National Needs Assessment for Ensuring Transportation
Infrastructure Security, National Cooperative Highway Research Program,
Washington, DC, 2002.
[4] Minnesota Department of Employment and Economic Development and
Minnesota Department of Transportation, Economic Impacts of the I-35W Bridge
Collapse, Minneapolis, MN, 2007
[5] Federal Highway Administration, Our Nation’s Highways, US Department of
Transportation, Washington, DC, 2002
[6] American Association of State Highway and Transportation Officials, 2003
Survey of State Transportation Agencies–Summary of Results, Washington, DC,
2004
[7] National Highway Cooperative Research Program, Fundamentals of
Transportation Security for State Transportation Agencies, NCHRP Report 20-59
(16B) Transportation Research Board, Washington, D.C., Forthcoming
[8] ibid
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Further reading list
Blue Ribbon Panel on Bridge and Tunnel Security, Recommendations for Bridge
and Tunnel Security, US Department of Transportation, Washington, D.C., 2003
National Highway Cooperative Research Program, Responding to Threats: A
Field Personnel Manual, NCHRP Report 525, Volume 1, Transportation
Research Board, Washington, D.C., 2004
National Highway Cooperative Research Program, Continuity of Operations
Plans for Transportation Agencies, NCHRP Report 20-59 (21), Transportation
Research Board, Washington, D.C., 2005
National Highway Cooperative Research Program, Guidelines for Transportation
Emergency Training Exercises, NCHRP Report 525, Volume 9, Transportation
Research Board, Washington, D.C., 2006
National Highway Cooperative Research Program, Making Transportation
Tunnels Safe and Secure, NCHRP Report 525, Volume 12, Transportation
Research Board, Washington, D.C., 2006
National Highway Cooperative Research Program, Guide to Risk Management of
Multimodal Transportation Infrastructure, NCHRP Report 20-59 (17)
Transportation Research Board, Washington, D.C., Forthcoming
National Highway Cooperative Research Program, A Guide to Emergency
Response Planning at State Transportation Agencies, NCHRP Report 20-59 (23)
Transportation Research Board, Washington, D.C., Forthcoming
Volpe Institute, Disaster Case Studies Series (New York/Washington DC,
Baltimore Train Fire, East Coast Blackout, Northridge Earthquake), Boston,
Massachusetts, 2004
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