Interstate Highway Security Systems

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 against terrorist threat 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.

The FHWA is collaborating extensively with the American Association of State Highway and Transportation Officials (AASHTO) to concentrate on the most effective highway security initiatives, some of which include:

• Developing and distributing best practices for determining critical highway infrastructure, assessing vulnerability to attack, and developing effective countermeasures
• Assembling a nationally recognized panel of structural experts to advise on short- and long-term strategies for improving the security of critical bridges and tunnels
• Facilitating a series of workshops throughout the country to improve emergency preparedness for response and recovery to attacks and other disruptive events
• Engaging in national dialogues to develop priorities for security research and training

FHWA held a workshop at Turner-Fairbank Highway Research Center (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 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 Blue Ribbon Pannel (BRP) of bridge and tunnel experts concluded that in many parts of the country, the transportation system is straining to keep up with the current demands of society and the economy. The actions of terrorists can impose critical damage to some bridges, and, with explosive forces, exert loads that exceed those for which components are currently being designed. Worse yet, in some cases, the loads can be in the opposite direction of the conventional design loads.

Among the 600,000 bridges in the United States, preliminary studies indicate that there are approximately 1,000 where substantial casualties, economic disruption, and other societal ramifications would result from isolated attacks.5 Additionally, the U.S. transportation system includes 337 highway tunnels and 211 transit tunnels; many are located beneath bodies of water, and many have limited alternative routes due to geographic constraints.6 The BRP recommends prioritization of these bridge and tunnel assets, followed by risk assessment as a guide for allocating federal and state funds to address security concerns, and then implementation of cost-effective operational security measures and engineering design standards to reduce the vulnerability of high priority bridges and tunnels to terrorist attacks.