The nation’s transportation system is a vast, interconnected network of diverse modes. Key modes of transportation include aviation; highways; motor carrier (i.e., trucking); motor coach (i.e., intercity bus); maritime; pipeline; rail (passenger and freight); and transit (e.g., buses, subways, ferry boats, and light rail). The transportation modes work in harmony to facilitate mobility through an extensive network of infrastructure and operators, as well as through the vehicles and vessels that permit passengers and freight to move within the system. For example, the nation’s transportation system moves over 30 million tons of freight and provides approximately 1.1 billion passenger trips each day. The diversity and size of the transportation system make it vital to our economy and national security, including military mobilization and deployment. Private industry, state and local governments, and the federal government all have roles and responsibilities in securing the transportation system. Private industry owns and operates a large share of the transportation system. For example, almost 2,000 pipeline companies and 571 railroad companies own and operate the pipeline and freight railroad systems, respectively. Additionally, 83 passenger air carriers and 640,000 interstate motor coach and motor carrier companies operate in the United States. State and local governments also own significant portions of the highways, transit systems, and airports in the country. For example, state and local governments own over 90 percent of the total mileage of highways. State and local governments also administer and implement regulations for different sectors of the transportation system and provide protective and emergency response services through various agencies. Although the federal government owns a limited share of the transportation system, it issues regulations, establishes policies, provides funding, and/or sets standards for the different modes of transportation. The federal government uses a variety of policy tools, including grants, loan guarantees, tax incentives, regulations, and partnerships, to motivate or mandate state and local governments or the private sector to help address security concerns. Prior to September 11, DOT was the primary federal entity involved in transportation security matters. However, in response to the attacks on September 11, Congress passed the Aviation and Transportation Security Act (ATSA), which created TSA within DOT and defined its primary responsibility as ensuring security in all modes of transportation. The act also gives TSA regulatory authority over all transportation modes. Since its creation in November 2001, TSA has focused primarily on meeting the aviation security deadlines contained in ATSA. With the passage of the Homeland Security Act on November 25, 2002, TSA, along with over 20 other agencies, was transferred to the new Department of Homeland Security (DHS). The United States maintains the world’s largest and most complex national transportation system. Improving the security of such a system is fraught with challenges for both public and private entities. To provide safe transportation for the nation, these entities must overcome issues common to all modes of transportation as well as issues specific to the individual modes of transportation. Although each mode of transportation is unique, they all face some common challenges in trying to enhance security. Common challenges stem from the extensiveness of the transportation system, the interconnectivity of the system, funding security improvements, and the number of stakeholders involved in transportation security. The size of the transportation system makes it difficult to adequately secure. The transportation system’s extensive infrastructure crisscrosses the nation and extends beyond our borders to move millions of passengers and tons of freight each day. The extensiveness of the infrastructure as well as the sheer volume of freight and passengers moved through the system creates an infinite number of targets for terrorists. Furthermore, as industry representatives and transportation security experts repeatedly noted, the extensiveness of the infrastructure makes equal protection for all assets impossible. Protecting transportation assets from attack is made more difficult because of the tremendous variety of transportation operators. Some are multibillion-dollar enterprises, and others have very limited facilities and very little traffic. Some are public agencies, such as state departments of transportation, and some are private businesses. Some transportation operators carry passengers, and others haul freight. Additionally, the type of freight moved through the different modes is similarly varied. For example, the maritime, motor carrier, and rail operators haul freight as diverse as dry bulk (grain) and hazardous materials. Additional challenges are created by the interconnectivity and interdependency among the transportation modes and between the transportation sector and nearly every other sector of the economy. The transportation system is interconnected or intermodal because passengers and freight can use multiple modes of transportation to reach a destination. For example, from its point of origin to its destination, a piece of freight, such as a shipping container, can move from ship to train to truck. (See fig. 1.) The interconnective nature of the transportation system creates several security challenges. First, the effects of events directed at one mode of transportation can ripple throughout the entire system. For example, when the port workers in California, Oregon, and Washington went on strike in 2002, the railroads saw their intermodal traffic decline by almost 30 percent during the first week of the strike, compared with the year before. Second, the interconnecting modes can contaminate each other—that is, if a particular mode experiences a security breach, the breach could affect other modes. An example of this would be if a shipping container that held a weapon of mass destruction arrived at a U.S. port where it was placed on a truck or train. In this case, although the original security breach occurred in the port, the rail or trucking industry would be affected as well. Thus, even if operators within one mode established high levels of security they could be affected because of the security efforts, or lack thereof, of the other modes. Third, intermodal facilities where a number of modes connect and interact—such as ports— are potential targets for attack because of the presence of passengers, freight, employees, and equipment at these facilities. Interdependencies also exist between transportation and nearly every other sector of the economy. Consequently, an event that affects the transportation sector can have serious impacts on other industries. For example, when the war in Afghanistan began in October 2001, the rail industry restricted the movement of many hazardous materials, including chlorine, because of a heightened threat of a terrorist attack. However, within days, many major water treatment facilities reported that they were running out of chlorine, which they use to treat drinking water, and would have to shut down operations if chlorine deliveries were not immediately resumed. Securing the transportation system is made more difficult because of the number of stakeholders involved. As illustrated in figure 2, numerous entities at the federal, state, and local levels, including over 20 federal entities and thousands of private sector businesses, play a key role in transportation security. For example, the Departments of Energy, Transportation, and Homeland Security; state governments; and about 2,000 pipeline operators are all responsible for securing the pipeline system. The number of stakeholders involved in transportation security can lead to communication challenges, duplication, and conflicting guidance. Representatives from several state and local government and industry associations told us that their members are receiving different messages from the various federal agencies involved in transportation security. For instance, one industry representative noted that both TSA and DOT asked the industry to implement additional security measures when the nation’s threat condition was elevated to orange at the beginning of the Iraq War; however, TSA and DOT were not consistent in what they wanted done—that is, they were asking for different security measures. Moreover, many representatives commented that the federal government needs to better coordinate its security efforts. These representatives noted that dealing with multiple agencies on the same issues and topics is frustrating and time consuming for the transportation sector. The number of stakeholders also makes it difficult to achieve the needed cooperation and consensus to move forward with security efforts. As we have noted in past reports, coordination and consensus-building are critical to successful implementation of security efforts. Transportation stakeholders can have inconsistent goals or interests, which can make consensus-building challenging. For example, from a safety perspective, vehicles that carry hazardous materials should be required to have placards that identify the contents of a vehicle so that emergency personnel know how best to respond to an incident. However, from a security perspective, identifying placards on vehicles that carry hazardous materials make them a potential target for attack. According to transportation security experts and state and local government and industry representatives we contacted, funding is the most pressing challenge to securing the nation’s transportation system. Although some security improvements are inexpensive, such as removing trash cans from subway platforms, most require substantial funding. Additionally, given the large number of assets to protect, the sum of even relatively less expensive investments can be cost prohibitive. For example, reinforcing shipping containers to make them more blast resistant is one way to improve security, which would cost about $15,000 per container. With several million shipping containers in use, however, this tactic would cost billions of dollars if all of them were reinforced. The total cost of enhancing the security of the entire transportation system is unknown; however, given the size of the system, it could amount to tens of billions of dollars. The current economic environment makes this a difficult time for private industry or state and local governments to make security investments. According to industry representatives and experts we contacted, most of the transportation industry operates on a very thin profit margin, making it difficult for the industry to pay for additional security measures. The sluggish economy has further weakened the transportation industry’s financial condition by decreasing ridership and revenues. For example, airlines are in the worst fiscal crisis in their history, and several have filed for bankruptcy. Similarly, the motor coach and motor carrier industries and Amtrak report decreased revenues because of the slow economy. In addition, nearly every state and local government is facing a large budget deficit for fiscal year 2004. For example, the National Governors Association estimates that states are facing a total budget shortfall of $80 billion for fiscal year 2004.