Though they may not always be the intended target of a terrorist attack, highway assets will always be critical to America’s ability to respond and recover from such an event. Bridges and tunnels, critical links in the 3.9 million-mile highway system that carries 86 percent of personal travel and 80 percent of the nation’s freight, are by their nature exposed to vehicles that can be used to deliver an explosive blast, exposing users and vulnerable structural elements to these blast effects. Owners, operators, and emergency responders have considerable experience with accidental fire and collision incidents that routinely take their facilities out of service, tactics terrorists may use to destroy a structure intentionally. In addition, the transportation community must consider threats from mechanical and chemical cutting devices, radiological and chemical agent dispersal, and even cyber-attack. These are problems in search of solutions to deter aggressors and minimize consequences.
The Federal Highway Administration (FHWA) has twin priorities in addressing transportation security: Emergency response and risk management. These are broad concepts that rely on national, regional, statewide, local, and interagency partnerships to establish layered and integrated security solutions. Security must be layered to assure that aggressors have to overcome multiple obstacles to achieve their goals. The Department of Homeland Security (DHS) and local agencies play leading roles in the effort to protect our borders and remove potential threats long before they can impact our facilities. State and local law enforcement provide a visible security presence with routine and random patrols and their criminal investigations also deter criminal activity. Closer to potential targets, facility screening and intrusion detection technology can identify threats. Physical barriers can provide a buffer zone of protection. Safety and structural resistance can be designed into our facilities and we can plan for emergency response and recovery to minimize the consequences from terrorist acts or other hazards. These protective and response measures must be integrated to optimize their effectiveness.
Designing and building successful transportation projects that take security considerations into account requires understanding that emergency management is critical to all other protective measures and that risk management is the tool to develop cost-effective projects. Against the backdrop of these two concepts, design-build delivery for these projects reveals significant potential advantages over traditional approaches.
Emergency Response
The ability to respond quickly to incidents and emergencies has multiple benefits for safety, security, and optimized operation. Detecting a vehicular incident and responding to it promptly provides improved safety for motorists who are primarily affected, fewer backups for highway users secondarily affected, and provides a complicating factor for someone planning an attack. Among all the protective measures that a transportation department must consider both for its operations and when designing new facilities, emergency response and recovery is the most critical function to save lives, mitigate damage, and accelerate repair and reconstruction. This is not to minimize the important role of risk management in the overall process, it is simply to highlight the fact that the outcome of an incident can be greatly determined by overall response.
Training is important to emergency response and recovery planning. Tabletop exercises are particularly useful for improving readiness. Many DOT’s have experience with these exercises, using them to practice for flood, earthquake, or hurricane emergencies — even to simulate a terrorist attack — and better understand how to respond to multiple, cascading events and avoid catastrophic consequences. Key to this process is to include everyone who may be involved in the response and recovery: fire, police, medical personnel, highway maintenance personnel, facility operators, owners, managers, and others. Good relationships and good communications between those who will contribute to response and recovery are a primary benefit of this type of training.
Risk Management
Risk management is a scientific approach to making cost-effective decisions about security expenditures. This is the same process that can be used to assess risk for flood, earthquake, and hurricane or other rare but recurring natural events. It is a well-tested process, having been used to manage risk for earthquake events for over 20 years and also allows comparing risks from all hazards with the aim to manage scarce resources. Risk assessment and risk management are necessary to developing an effective infrastructure protection plan.
Assessing security risk is a multi-disciplinary effort, requiring input from law enforcement, facility owners and operators, and engineers. Infrastructure owners, who best understand their structures, facility operations, and economic concerns, must lead the assessment. They must also assure involvement from many disciplines: law enforcement officials who understand the threat; first responders who will deal with any incident and have experience with response planning; maintenance personnel who are often the first on the incident scene and important to recovery efforts; traffic management professionals; structural engineers; planners and designers.
No matter what mitigation measures are taken, risk from attack can never be entirely eliminated, but risk reduction can be measured. This is accomplished by developing and prioritizing mitigation projects and comparing the project cost to the benefit from project implementation (risk reduction).
The risk model frames risk by looking at three major factors. One is the “threat,” or the likelihood that the asset will be a target. A second factor is vulnerability, the likely degree of damage to the bridge or tunnel if it is attacked. The third is the importance of the structure, reflecting the consequence from damage or loss, and would be the same value if the facility were damaged by a natural disaster.
All mitigation projects are evaluated for their cost and the amount of risk reduction they can provide. This compilation of ranked projects allows facility owners to make informed decisions about which security measures are appropriate to include in their planning process and which measures may be too expensive or provide too little benefit.
Designing Security for Transportation Projects
Designing cost-effective security into a bridge or tunnel project requires involvement early in the process, preferably during the risk assessment. Refined cost estimates and design innovations can improve confidence in the project selection process and establish realistic expectations for performance. Designers must consider solutions that have response and recovery as their cornerstone and, for bridges and tunnels, designers should consider measures that maximize standoff distance to keep potential threats as far away from critical elements as possible. When adequate standoff is not possible, engineered, structural toughening may be the best solution. It is also important to note that designing security into new projects is much more cost-effective than trying to retrofit existing facilities. Confinement steel reinforcing, slightly larger columns, improved geometry, and added redundancy can be low-cost solutions in the design phase and expensive, if not impossible, as retrofits. Roadway geometry and land-use issues, such as where or whether to allow parking, have security implications that are best addressed early in project planning and with design input.
Design-Build for Security
Owners are responsible for defining the threats to their facilities and determining the acceptable risk for design. Using a risk management approach makes this determination defensible. Once the acceptable risk is established, owners must also establish standards for security considerations in transportation projects, since the existing American Association of State Highway and Transportation Officials (AASHTO) Bridge Design Specifications do not currently address blast loadings or prescribe design solutions. AASHTO is addressing this and other highway infrastructure security issues through its Special Committee on Security and a separate Technical Committee on Security. In addition, research at FHWA and the National Cooperative Highway Research Program is underway to advance blast loading guidance and standards.
The designer must understand blast phenomenology, how to apply available blast analysis and design tools, and what mitigation strategies are available. For bridges and tunnels, designers must rely on experience from the vertical construction industry where there is a history of designing against terrorist threats. Some defensive strategies for buildings are directly applicable to bridges and tunnels, but highway infrastructure poses unique challenges that require innovative solutions. For transportation structures, some security solutions have either not yet been discovered, are being researched, or are available only from non-traditional sources. Designers, builders, and owners must work together to discover effective projects.
Builders must consider that they may be working with unusual features, different than those found on the typical bridge project. Robust reinforcing schemes, larger members, unfamiliar materials or configurations may be required. The design-build delivery process can provide incentives to address this and other project issues, with a properly written scope of work that allows proposers to submit innovative technical and price options. For these situations, the “design-build project delivery” method has several advantages over the traditional “design-bid-build” method. Design-build allows the contracting agency to meet with proposers at an early stage to gather information concerning the appropriate risk allocation strategies. The contracting agency may then develop a scope of work for the Request for Proposal document that provides incentives for proposers to provide time saving, innovative, and cost-effective technical solutions. The contracting agency may then select the best-value proposal based on the evaluation criteria identified in the solicitation.
Design-build may also offer the advantage to reduce overall project delivery time, reduce the potential for cost growth with lump-sum pricing, provide options for the owner based on price and non-price considerations, and reduce the potential for changes and claims. Design-build contracts require good management, and projects with critical security components greatly benefit from this hands-on owner involvement.
These projects most often require that sensitive information be protected and a growing number of facility owners are requiring background checks for design and construction personnel. A design-build contract can offer the advantage of a single certification for a company’s personnel security plan and reduce owner risk.
Many of the potential advantages of design-build contracts are made clear in post-event projects. A structure damaged by fire or terrorist attack may require rapid restoration, a key advantage to the design-build model. Often, rapid replacement is the best available security mitigation, and it is reasonable to pre-plan projects and pre-certify contractors to enable quick recovery from catastrophic events.
Summary
A Blue Ribbon Panel on Bridge and Tunnel Security concluded that the threat from terrorist threats is real and has the potential for casualties, economic disruption, and other societal impacts. They recommend risk assessment to prioritize funding for security measures to reduce the vulnerability of high-priority bridges and tunnels. This risk assessment model can be used, not just to rank critical facilities, but also to develop and rank cost-effective security projects to include in capital investment plans. Security can only be achieved by involving many disciplines, including designers and builders, to develop a layered, integrated security plan that has emergency management and risk assessment as its cornerstone. Design-build delivery is an essential tool for this integrated plan.
Acknowledgments
Gerald Yakowenko of the Federal Highway Administration authored the SAFETEA-LU discussion, as well as offering his insights into some of the strategic advantages of design-build. Credit is also due Joe Englot, Port Authority of New York and New Jersey, for the diagram of “Layered, Integrated Security System.”
Steve Ernst is Senior Bridge Engineer, Safety and Security, Federal Highway Administration, Office of Bridge Technology. He has worked with the Federal Highway Administration for 21 years, including nine years as a bridge designer and ten years as a structural engineer in Federal Highways’ Office of Bridge Technology. Mr. Ernst is currently responsible for bridge and structures technology programs, including policies, procedures, standards, and practices related to safety and security in bridge structures engineering.
Mr. Ernst serves as the FHWA lead for vulnerability assessment for critical infrastructure and interaction with the Department of Homeland Security and other U.S. agencies on bridge and tunnel security issues. He is liaison to the AASHTO Technical Committee on Security and the Special Committee on Security and has developed with the U.S. Army Corps of Engineers a workshop to train engineers to understand and mitigate terrorist threats to highway assets. Mr. Ernst was also the FHWA lead for the Blue Ribbon Panel on Bridge and Tunnel Security and is currently involved with several research projects for structural hardening. He may be reached at steve. ernst@fhwa.dot.gov.