Technology Assessment: Explosives Detection Technologies to Protect Passenger Rail
Published: 2010-07-28T00:00:00

Fast Facts:

Highlights:
section_title: Why GAO Did This Study
paragraphs: Passenger rail systems are vital to the nation's transportation infrastructure, providing approximately 14 million passenger trips each weekday. Recent terrorist attacks on these systems around the world--such as in Moscow, Russia in 2010--highlight the vulnerability of these systems. The Department of Homeland Security's (DHS) Transportation Security Administration (TSA) is the primary federal entity responsible for securing passenger rail systems. In response to the Legislative Branch Appropriations Act for fiscal year 2008, GAO conducted a technology assessment that reviews 1) the availability of explosives detection technologies and their ability to help secure the passenger rail environment, and 2) key operational and policy factors that impact the role of explosives detection technologies in the passenger rail environment. GAO analyzed test reports on various explosives detection technologies and convened a panel of experts comprised of a broad mix of federal, technology, and passenger rail industry officials. GAO also interviewed officials from DHS and the Departments of Defense, Energy, Transportation, and Justice to discuss the effectiveness of these technologies and their applicability to passenger rail. GAO provided a draft of this report these departments for comment. Four departments provided technical comments, which we incorporated as appropriate.
section_title: What GAO Found
paragraphs: A variety of explosives detection technologies are available or in development that could help secure passenger rail systems. While these technologies show promise in certain environments, their potential limitations in the rail environment need to be considered and their use tailored to individual rail systems. The established technologies, such as handheld, desktop, and kitbased trace detection systems, and x-ray imaging systems, as well as canines, have demonstrated good detection capability with many conventional explosive threats and some are in use in passenger rail today. Newer technologies, such as explosive trace portals, advanced imaging technology, and standoff detection systems, while available, are in various stages of maturity and more operational experience would be required to determine their likely performance if deployed in passenger rail. When deploying any of these technologies to secure passenger rail, it is important to take into account the inherent limitations of the underlying technologies as well as other considerations such as screening throughput, mobility, and durability, and physical space limitations in stations.
section_title: What GAO Recommends
paragraphs: GAO is not making recommendations, but is raising various policy considerations. For example, in addition to how well technologies detect explosives, GAO's work, in consultation with rail and technology experts, identified several key operational and policy considerations impacting the role that these technologies can play in securing the passenger rail environment. Specifically, while there is a shared responsibility for securing the passenger rail environment, the federal government, including TSA, and passenger rail operators have differing roles, which could complicate decisions to fund and implement explosives detection technologies. For example, TSA provides guidance and some funding for passenger rail security, but rail operators themselves provide day-to-day-security of their systems. In addition, risk management principles could be used to guide decision-making related to technology and other security measures and target limited resources to those areas at greatest risk. Moreover, securing passenger rail involves multiple security measures, with explosives detection technologies just one of several components that policymakers can consider as part of the overall security environment. Furthermore, developing a concept of operations for using these technologies and responding to threats that they may identify would help balance security with the need to maintain the efficient and free flowing movement of people. A concept of operations could include a response plan for how rail employees should react to an alarm when a particular technology detects an explosive. Lastly, in determining whether and how to implement these technologies, federal agencies and rail operators will likely be confronted with challenges related to the costs and potential privacy and legal implications of using explosives detection technologies.

section_title: Letter
paragraphs: Passenger rail systems are vital components of the nation’s transportation  infrastructure, encompassing rail transit (heavy rail, commuter rail, and  light rail), and intercity rail. In the United States, passenger rail systems  provide approximately 14 million passenger trips each weekday, and  commuters rely on these systems to provide efficient, reliable, and safe  transportation. Terrorist attacks on passenger rail systems around the  world—such as the March 2010 Moscow, Russia subway bombings, and  the July 2006 passenger train bombing in Mumbai, India that resulted in  209 fatalities—highlight the vulnerability of these systems. Additionally,  the administration’s Transborder Security Interagency Policy Committee,  Surface Transportation Subcommittee’s recently issued Surface  Transportation Security Priority Assessment stated that the nation’s  transportation network was at an elevated risk of attack and that recent  plots against passenger rail highlight the lengths terrorists will go to defeat  security measures put in place after September 11, 2001. Another threat  facing passenger rail systems are chemical and biological weapons. While  there have been no terrorist attacks against U.S. passenger rail systems to  date, the systems are vulnerable to attack in part because they rely on an  open architecture that is difficult to monitor and secure due to its multiple  access points, hubs serving multiple carriers, and, in some cases, no  barriers to access. Further, an attack on these systems could potentially  lead to casualties due to the high number of daily passengers, especially  during peak commuting hours, and result in serious economic disruption  and psychological impact.
Day-to-day responsibility for securing passenger rail systems falls on  passenger rail operators, local law enforcement, and state and local  governments that own portions of the infrastructure. While several entities  play a role in helping to fund and secure U.S. passenger rail systems, the  Department of Homeland Security’s (DHS) Transportation Security  Administration (TSA) is the primary federal agency responsible for  overseeing security for these systems and for developing a national  strategy and implementing programs to enhance their security. The  Department of Transportation’s (DOT) Federal Transit Administration  (FTA) and Federal Railroad Administration (FRA) also provide support to  rail operators by providing technical assistance in conducting threat and  vulnerability assessments and developing and providing training courses  for rail operators. Additionally, several other DHS components conduct  threat and vulnerability assessments of passenger rail systems, research  and develop security technologies for these systems, and develop security  training programs for passenger rail employees. We have previously  reported, most recently in June 2009, on federal and industry efforts to  secure passenger rail systems and have made recommendations for  strengthening these efforts. DHS generally agreed with these  recommendations and is taking action to implement them.
A variety of security measures, including technological measures, have  been and are being considered by federal policymakers and rail operators  as part of a layered approach to strengthening the security of passenger  rail systems, particularly in the area of protecting against the threat of  explosives. Explosives detection technologies have been tested and  implemented for screening passengers and baggage in aviation and  building security. Further, the U.S. military uses some of these  technologies to, among other things, detect the presence of improvised  explosive devices (IED) in Iraq and Afghanistan. However, these  technologies have been tested and implemented less frequently in  passenger rail systems. This is due in part to the open nature of passenger  rail systems, which does not lend itself to people and baggage screening.  Also, there is relatively less funding available to support the purchase and  maintenance of such equipment compared to the funding available for  commercial aviation security in which the federal government plays a  larger role. Because of the potential impact of implementation of  explosives detection technology on the open nature of passenger rail  systems, weighing rail operator needs and technological effectiveness of  explosives detection technology against the relative costs and impact on  rail operations is important. Additionally, because these explosives  detection technologies tend to be expensive, rail operators may look to  other funding sources, such as the federal government, to assist in  implementing these technologies.
In the Senate report accompanying the proposed bill for the legislative  branch fiscal year 2008 appropriation, the Senate Committee on  Appropriations recommended the establishment of a permanent  technology assessment function within GAO. In the 2008 Consolidated  Appropriations Act, Congress authorized GAO to use up to $2.5 million of  amounts appropriated for salaries and expenses for technology  assessment studies. After consultation with congressional committees,  GAO agreed to conduct a technology assessment on the use of explosives  detection technologies to secure passenger rail systems. Specifically, this  report addresses the following questions:  1.  What is the availability of explosives detection technologies and what  is their ability to help secure the passenger rail environment?  2.  What key operational and policy factors could have an impact on the  role of explosives detection technologies in the passenger rail  environment?
This report is a public version of the restricted report (GAO-10-590SU) that  we provided to you on May 28, 2010. DHS deemed some of the information  in the restricted report as sensitive security information, which must be  protected from public disclosure. Therefore, this report omits this  information. Although the information provided in this report is more  limited in scope, it addresses the same questions as the restricted report.  Also, the overall methodology used for both reports is the same.
To determine what explosives detection technologies are available and  their ability to help secure the passenger rail environment, we met with  experts and officials on explosives detection research, development, and  testing, and reviewed test, evaluation, and pilot reports and other  documentation from DHS’s Science and Technology Directorate, including  the Transportation Security Laboratory; TSA; several Department of  Defense (DOD) components, including the Naval Explosive Ordnance  Disposal Technology Division (NAVEODTECHDIV), the Technical Support  Working Group (TSWG), and the Joint Improvised Explosive Device  Defeat Organization (JIEDDO); several Department of Energy (DOE)  National Laboratories involved in explosives detection testing, research,  and development including Los Alamos National Laboratory (LANL),  Sandia National Laboratories (SNL), and Oak Ridge National Laboratory  (ORNL); and the Department of Justice (DOJ) because of its expertise in  explosives detection. We also observed a TSA pilot test of a standoff  explosives detection system at a rail station within the Port Authority  Trans-Hudson passenger rail system. In addition, we interviewed several  manufacturers of explosives detection technologies and attended  government-sponsored demonstrations, a conference, and an academic  workshop on explosives detection technologies. We also interviewed  government officials involved with securing passenger rail in the United  Kingdom. We visited six domestic passenger rail locations, two of which  were involved in testing various types of explosives detection technologies  to either observe the testing or discuss the results of these tests with  operators. The specific locations we visited are listed in appendix I.
In determining which explosives detection technologies were available  and able to secure the passenger rail environment, we considered those  technologies available today or deployable within 5 years, technologies  which could be used to screen either passengers or their carry-on items,  and technologies which were safe to use when deployed in public areas. In  determining the capabilities and limitations of explosives detection  technologies we evaluated their detection and screening throughput  performance, reliability, availability, cost, operational specifications, and  possible use in passenger rail. We also restricted our evaluation to those  technologies which have been demonstrated to detect explosives when  tested against performance parameters as established by government and  military users of the technologies.
We also obtained the views of various experts and stakeholders during a  panel discussion we convened with the assistance of the National  Research Council (NRC) in August 2009 (hereafter referred to as the  expert panel). Panel attendees included 23 experts and officials from  academia, the federal government, domestic and foreign passenger rail  industry organizations, technology manufacturers, national laboratories,  and passenger rail industry stakeholders such as local law enforcement  officials and domestic and foreign passenger rail operators. During this  meeting, we discussed the availability and applicability of explosives  detection technologies for the passenger rail environment and the  operational and policy impacts associated with implementing these  technologies in the rail environment. While the views expressed during  this panel are not generalizable across all fields represented by officials in  attendance, they did provide an overall summary of the current availability  and effectiveness of explosives detection technologies and industry views  on their applicability to passenger rail.
To determine what key operational and policy factors could have an  impact in determining the role of explosives detection technologies in the  passenger rail environment, we reviewed documentation related to the  federal strategy for securing passenger rail, including TSA’s Mass Transit  Modal Annex to the Transportation Systems Sector Specific Plan, and  other documentation, including DHS reports summarizing explosives  detection technology tests conducted in passenger rail to better  understand the role and impact that these technologies have in the  passenger rail environment. We reviewed relevant laws and regulations  governing the security of the transportation sector as a whole and  passenger rail specifically, including the Implementing Recommendations  of the 9/11 Commission Act. We also reviewed our prior reports on  passenger rail security and studies and reports conducted by outside  organizations related to passenger rail or the use of technology to secure  passenger rail, such as the National Academies, Congressional Research  Service, and others to better understand the existing security measures  used in passenger rail and operational and policy issues. During our  interviews and expert panel mentioned above, we also discussed and  identified officials’ views related to the key operational and policy issues  of using explosives detection technologies to secure passenger rail. While  these views are not generalizeable to all industries represented by these  officials, they provided a snapshot of the key operational and policy views.
During our visits to 6 rail operator locations involved in explosives  detection testing, we interviewed officials regarding operational and policy  issues related to technology and observed passenger rail operations. We  selected these locations because they had completed or were currently  conducting testing of the use of explosives detection technology in the rail  environment and to provide the views of a cross-section of heavy rail,  commuter rail, and light rail operators. While these locations and officials’  views are not generalizeable to the entire passenger rail industry, they  provided us with a general understanding of the operational and policy  issues associated with using such technologies in the rail environment. In  addition, we utilized information obtained and presented in our June 2009  report on passenger rail security. For that work, we conducted site visits,  or interviewed security and management officials from 30 passenger rail  agencies across the United States and met with officials from two regional  transit authorities and Amtrak. The passenger rail operators we visited or  interviewed for our June 2009 report represented 75 percent of the  nation’s total passenger rail ridership based on the information we  obtained from the FTA’s National Transit Database and the American  Public Transportation Association. For additional information on our  scope and methodology please see appendix I.
We conducted our work from August 2008 through July 2010 in  accordance with all sections of GAO’s Quality Assurance Framework that  are relevant to Technology Assessments. The framework requires that we  plan and perform the engagement to obtain sufficient and appropriate  evidence to meet our stated objectives and to discuss any limitations to  our work. We believe that the information and data obtained, and the  analysis conducted, provide a reasonable basis for any findings and  conclusions in this product.
subsections: section_title: Background
subsections: section_title: Overview of the U.S. Passenger Rail System
paragraphs: Passenger rail systems provided 10.7 billion passenger trips in the United  States in 2008. The nation’s passenger rail systems include all services  designed to transport customers on local and regional routes, such as  heavy rail, commuter rail, and light rail services. Heavy rail systems–– subway systems like New York City’s transit system and Washington,  D.C.’s Metro––typically operate on fixed rail lines within a metropolitan  area and have the capacity for a heavy volume of traffic. Commuter rail  systems typically operate on railroad tracks and provide regional service  (e.g., between a central city and adjacent suburbs). Light rail systems are  typically characterized by lightweight passenger rail cars that operate on  track that is not separated from vehicular traffic for much of the way. All  types of passenger rail systems in the United States are typically owned  and operated by public sector entities, such as state and regional  transportation authorities.
Amtrak, which provided more than 27 million passenger trips in fiscal year  2009, operates the nation’s primary intercity passenger rail and serves  more than 500 stations in 46 states and the District of Columbia. Amtrak  operates a more than 22,000 mile network, primarily over leased freight  railroad tracks. In addition to leased tracks, Amtrak owns about 650 miles  of track, primarily on the “Northeast Corridor” between Boston and  Washington D.C., which carries about two-thirds of Amtrak’s total  ridership. Stations are owned by Amtrak, freight carriers, municipalities,  and private entities. Amtrak also operates commuter rail services in  certain jurisdictions on behalf of state and regional transportation  authorities. Figure 1 identifies the geographic location of passenger rail  systems and Amtrak within the United States as of January 1, 2010.
Passenger rail operators that we spoke to and that attended our expert  panel indicated that rail stations in the United States generally fall into one  of three categories:    Heavy rail station. These stations are generally heavily traveled—serving  thousands of passengers during rush hours—and are located in major  metropolitan areas. They are usually space constrained and located either  underground or on an elevated platform and serviced by heavy rail. Entry  to the stations is usually controlled by turnstiles and other chokepoints.  Many of the subway stations in New York City and elevated stations in  Chicago are examples of these types of stations. See figure 2 for an  example of a typical heavy rail station.
Large intermodal station. These stations are also heavily traveled and  service multiple types of rail including heavy rail, commuter rail, and  intercity passenger rail (such as Amtrak). These stations are usually not as  space constrained and access is usually restricted either by turnstiles or  naturally occurring chokepoints, such as escalators or doorways leading  to rail platforms. Examples of these types of stations include Union  Station in Washington, D.C. See figure 3 for an example of a typical large  intermodal station.
Commuter or light rail station. These stations are open and access is  generally not constrained by turnstiles and other chokepoints. These  stations are usually served by commuter rail systems in suburban or rural  areas outside of a metropolitan area or in the case of light rail may be  located physically on the city’s streets with no access barriers between the  city and the station stop. The stations are easily accessible, not usually  space constrained, and are often located outdoors. Examples of this type  of station include Virginia Railway Express commuter stations in suburban  Virginia and the Maryland Area Regional Commuter (MARC) stations in  Maryland. See figure 4 for an example of a commuter or light rail station.
section_title: Passenger Rail Systems Are Inherently Difficult to Secure and Vulnerable to Terrorist Attacks, Particularly Against the Threat From Explosives
paragraphs: To date, U.S. passenger rail systems have not been attacked by terrorists.  However, according to DHS, terrorists’ effective use of IEDs in rail attacks  elsewhere in the world suggests that IEDs pose the greatest threat to U.S.  rail systems. Rail systems in the United States have also received  heightened attention as several alleged terrorists’ plots have been  uncovered, including multiple plots against systems in the New York City  area. Worldwide, passenger rail systems have been the frequent target of  terrorist attacks. According to the Worldwide Incidents Tracking System  maintained by the National Counter Terrorism Center, from January 2004  through July 2008 there were 530 terrorist attacks worldwide against  passenger rail targets, resulting in more than 2,000 deaths and more than  9,000 injuries. Terrorist attacks include a 2007 attack on a passenger train  in India (68 fatalities and more than 13 injuries); 2005 attack on London’s  underground rail and bus systems (52 fatalities and more than 700  injuries); and 2004 attack on commuter rail trains in Madrid, Spain (191  fatalities and more than 1,800 injuries). More recently, in January 2008,  Spanish authorities arrested 14 suspected terrorists who were allegedly  connected to a plot to conduct terrorist attacks in Spain, Portugal,  Germany, and the United Kingdom, including an attack on the Barcelona  metro. The most common means of attack against passenger rail targets  has been through the use of IEDs, including attacks delivered by suicide  bombers.
According to passenger rail operators, the openness of passenger rail  systems can leave them vulnerable to terrorist attack. Further, other  characteristics of passenger rail systems––high ridership, expensive  infrastructure, economic importance, and location in large metropolitan  areas or tourist destinations––make them attractive targets for terrorists  because of the potential for mass casualties, economic damage, and  disruption. Moreover, these characteristics make passenger rail systems  difficult to secure. In addition, the multiple access points along extended  routes make the costs of securing each location prohibitive. Balancing the  potential economic impacts of security enhancements with the benefits of  such measures is a difficult challenge.
section_title: Multiple Stakeholders Share Responsibility for Securing Passenger Rail Systems
paragraphs: Securing the nation’s passenger rail systems is a shared responsibility  requiring coordinated action on the part of federal, state, and local  governments; the private sector; and passengers who ride these systems.  Since the September 11, 2001, terrorist attacks, the role of the federal  government in securing the nation’s transportation systems has evolved. In  response to attacks, Congress passed the Aviation and Transportation  Security Act (ATSA), which created TSA within DOT and conferred to the  agency broad responsibility for overseeing the security of all modes of  transportation, including passenger rail. Congress passed the Homeland  Security Act of 2002, which established DHS, transferred TSA from DOT to  DHS, and assigned DHS responsibility for protecting the nation from  terrorism, including securing the nation’s transportation systems. TSA is  supported in its efforts to secure passenger rail by other DHS entities such  as the National Protection and Programs Directorate (NPPD) and Federal  Emergency Management Administration’s (FEMA) Grant Programs  Directorate and Planning and Assistance Branch. NPPD is responsible for  coordinating efforts to protect the nation’s most critical assets across all  18 industry sectors, including transportation. FEMA’s Grant Programs  Directorate is responsible for managing DHS grants for mass transit.  FEMA’s Planning and Assistance Branch is responsible for assisting transit  agencies with conducting risk assessments.
While TSA is the lead federal agency for overseeing the security of all  transportation modes, DOT continues to play a supporting role in securing  passenger rail systems. In a 2004 Memorandum of Understanding and a  2005 annex to the Memorandum, TSA, and FTA agreed that the two  agencies would coordinate their programs and services, with FTA  providing technical assistance and assisting DHS with implementation of  its security policies, including collaborating in developing regulations  affecting transportation security. In addition to FTA, Federal Railroad  Administration (FRA) also has regulatory authority over commuter rail  operators and Amtrak and employs over 400 inspectors who periodically  monitor the implementation of safety and security plans at these systems.  FRA regulations require railroads that operate intercity or commuter  passenger train service or that host the operation of that service adopt and  comply with a written emergency preparedness plan approved by FRA.
In August 2007, the Implementing Recommendations of the 9/11  Commission Act was signed into law, which included provisions that  require TSA to take certain actions to secure passenger rail systems.  Among other items, these provisions include mandates for developing and  issuing reports on TSA’s strategy for securing public transportation,  conducting and updating security assessments of mass transit systems,  and establishing a program for conducting security exercises for rail  operators. The 9/11 Commission Act includes requirements for TSA to  increase the number of explosives detection canine teams and required  DHS to carry out a research and development program to secure  passenger rail systems.
State and local governments, passenger rail operators, and private industry  are also stakeholders in the nation’s passenger rail security efforts. State  and local governments might own or operate portions of passenger rail  systems. Consequently, the responsibility for responding to emergencies  involving systems that run through their jurisdictions often falls to state  and local governments. Although all levels of government are involved in  passenger rail security, the primary responsibility for securing the systems  rests with the passenger rail operators. These operators, which can be  public or private entities, are responsible for administering and managing  system activities and services, including security. Operators can directly  operate the security service provided or contract for all or part of the total  service. For example, the Washington Metropolitan Area Transit Authority  operates its own police force.
section_title: Federal and Industry Stakeholders Have Taken Actions to Secure Passenger Rail Systems
paragraphs: Federal stakeholders have taken actions to help secure passenger rail. For  example, in November 2008, TSA published a final rule that requires  passenger rail systems to appoint a security coordinator and report  potential threats and significant security concerns to TSA. In addition,  TSA developed the Transportation Systems-Sector Specific Plan (TS-SSP)  in 2007 to document the process to be used in carrying out the national  strategic priorities outlined in the National Infrastructure Protection Plan  (NIPP) and the National Strategy for Transportation Security (NSTS). The  TS-SSP contains supporting modal implementation plans for each  transportation mode, including mass transit and passenger rail. The Mass  Transit Modal Annex provides TSA’s overall strategy and goals for  securing passenger rail and mass transit, and identifies specific efforts  TSA is taking to strengthen security in this area.
DHS also provides funding to passenger rail operators for security,  including purchasing and installing security technologies, through the  Transit Security Grant Program (TSGP). We reported in June 2009 that  from fiscal years 2006 through 2008, DHS provided about $755 million  dollars to mass transit and passenger rail operators through the TSGP to  protect these systems and the public from terrorist attacks. Passenger  rail operators with whom we spoke and that attended our expert panel  said that they used these funds to acquire security assets including  explosives detection canines, handheld explosives detectors, closed  circuit television (CCTV) systems, and other security measures.
Passenger rail operators have also taken actions to secure their systems.  In September 2005, we reported that all 32 U.S. rail operators that we  interviewed or visited had taken actions to improve the security and safety  of their rail systems by, among other things, conducting customer  awareness campaigns; increasing the number and visibility of security  personnel; increasing the use of canine teams, employee training,  passenger and baggage screening practices, and CCTV and video analytics;  and strengthening rail system design and configuration. Passenger rail  operators stated that security-related spending by rail operators was based  in part on budgetary considerations, as well as other practices used by  other rail operators that were identified through direct contact or during  industry association meetings. According to the American Public  Transportation Association (APTA), in 2005, 54 percent of passenger rail  operators faced increasing deficits, and no operator covered expenses  with fare revenue; thus, balancing operational and capital improvements  with security-related investments has been an ongoing challenge for these  operators. Figure 5 provides a composite of selected security practices  used in the passenger rail environment.
K-9 patrol unit(s)
section_title: Types and Characteristics of Explosives and IEDs
paragraphs: Countering the explosives threat to passenger rail is a difficult challenge  as there are many types of explosives and different forms of bombs. The  many different types of explosives are loosely categorized as military,  commercial, and a third category called homemade explosives (HME)  because they can be constructed with unsophisticated techniques from  everyday materials. The military explosives include, among others, the  high explosives PETN and RDX, and the plastic explosives C-4 and  Semtex. The military uses these materials for a variety of purposes, such  as the explosive component of land mines, shells, or warheads. They also  have commercial uses such as for demolition, oil well perforation, and as  the explosive filler of detonation cords. Military explosives can only be  purchased domestically by legitimate buyers through explosives  distributors and typically terrorists have to resort to stealing or smuggling  to acquire them. RDX was used in the Mumbai passenger rail bombings of  July 2006. PETN was used by Richard Reid, the “shoe bomber” in his 2001  attempt to blow up an aircraft over the Atlantic Ocean, and was also a  component involved in the attempted bombing incident on board  Northwest Airline Flight 253 over Detroit on Christmas Day 2009.
Commercial explosives, with the exception of black and smokeless  powders, also can only be purchased domestically by legitimate buyers  through explosives distributors. These are often used in construction or  mining activities and include, among others, trinitrotoluene (TNT),  ammonium nitrate and aluminum powder, ammonium nitrate and fuel oil  (ANFO), black powder, dynamite, nitroglycerin, smokeless powder, and  urea nitrate. Dynamite was likely used in the 2004 Madrid train station  bombings, as well as the Sandy Springs, Georgia abortion clinic bombing  in January, 1997. ANFO was the explosive used in the Oklahoma City,  Oklahoma bombings in 1995.
The common commercial and military explosives contain various forms of  nitrogen. The presence of nitrogen is often exploited by detection  technologies some of which look specifically for nitrogen (nitro or nitrate  groups) in determining if a threat object is an explosive.
HMEs, on the other hand, can be created using household equipment and  ingredients readily available at common stores and do not necessarily  contain the familiar components of conventional explosives. On February  22, 2010, Najibullah Zazi pleaded guilty to, among other things, planning to  use TATP to attack the New York City subway system. Also, HMEs using  TATP and concentrated hydrogen peroxide, for example, were used in the  July 2005 London railway bombing. TATP can be synthesized from  hydrogen peroxide, a strong acid such as sulfuric acid, and acetone, a  chemical available in hardware stores and found in nail polish remover,  and HMTD can be synthesized from hydrogen peroxide, a weak acid such  as citric acid, and hexamine solid fuel tablets such as those used to fuel  some types of camp stoves and that can be purchased in many outdoor  recreational stores. ANFO is sometimes misrepresented as a homemade  explosive since both of its constituent parts—ammonium nitrate, a  fertilizer, and fuel oil—are commonly available.
When used, for example, in terrorist bombings, explosives are only one  component of an IED. Explosive systems are typically composed of a  control system, a detonator, a booster, and a main charge. The control  system is usually more mechanical or electrical in nature. The detonator  usually contains a small quantity of a primary or extremely sensitive  explosive. The booster and main charges are usually secondary explosives  which will not detonate without a strong shock, for example from a  detonator. IEDs will also have some type of packaging or, in the case of  suicide bombers, some type of harness or belt to attach the IED to the  body. Often, an IED will also contain packs of metal—such as nails, bolts,  or screws—or nonmetallic material which are intended to act as shrapnel  or fragmentation, increasing the IED’s lethality. The various components  of an IED—and not just the explosive itself—can also be the object of  detection.
The initiation hardware, which may be composed of wires, switches, and  batteries, sets off the primary charge in the detonator which, in turn,  provides the shock necessary to detonate the main charge. The primary  charge and the main charge are often different types and categories of  explosives. For example, in the attempted shoe bombing incident in 2001,  the detonator was a common fuse and paper-wrapped TATP, while PETN  was the main charge. While in the past the initiation hardware of many  IEDs contained power supplies, switches, and detonators, certain of the  newer HMEs do not require an electrical detonator but can be initiated by  an open flame.
section_title: A Variety of Explosives Detection Technologies Are Available or in Development That Could Help Secure Passenger Rail Systems—If Tailored to the Needs of Individual Rail Systems—but Limitations Exist
paragraphs: Several different types of explosives detection technologies could be  applied to help secure passenger rail, although operational constraints of  rail exist that would be important considerations. For example, handheld,  desktop, and kit explosives detection systems are portable and already in  use in the passenger rail environment. Carry-on item explosives detection  technologies are mature and can be effective in detecting some explosive  devices. Explosive Trace Portals generally use the same underlying  technology as handheld and desktop systems, and have been deployed in  aviation with limited success. Advanced Imaging Technology (AIT) portals  are becoming available but, as with trace portals, will likely have only  limited applicability in passenger rail. Standoff detection technologies  promise a detection capability without impeding the flow of passengers,  but have several limitations. Canines are currently used in passenger rail  systems, generally accepted by the public, and effective at detecting many  types of explosives. Limitations in these technologies restrict their more  widespread or more effective use in passenger rail and include limited  screening throughput and mobility, potential issues with environmental  conditions, and the openness and physical space restrictions of many rail  stations.
subsections: section_title: Various Explosives Detection Technologies Could be Applied to Help Secure Passenger Rail Systems If Operational Constraints of Rail are Effectively Considered
paragraphs: In the passenger rail environment detection of explosives involves the  screening of people and their carry-on baggage. The different types of  explosives detection technology available to address these screening  needs can be divided into two basic categories. There are those based on  imaging methods, sometimes called bulk detection, and those that are  based on trace detection methods. The goal in bulk detection is to identify  any suspicious indication—an anomaly—in a bag or on a person that  might potentially be a bomb. These systems, while they may be used to  detect explosive material, are also often used to detect other parts of a  bomb. Although some automated detection assistance is usually included,  imaging based detection systems currently depend heavily on trained  operators in identifying the anomalies indicative of a bomb.
Trace detection technologies, on the other hand, involve taking a physical  sample from a likely source and then analyzing it with any one of several  different techniques for the presence of trace particles of explosive  material. Importantly, a positive detection does not necessarily indicate  the presence of a bomb because the trace particles may just be  contamination from someone having handled or having been near  explosives material. Explosives trace detection systems can often identify  the individual type of explosives trace particles present.
Bulk and trace detection technology generally serve different functions  and can sometimes be paired to provide a more complete screening of a  person and their belongings. Typically that screening occurs in two stages.  First, an initial screening is done to separate suspicious persons or carry- on baggage from the rest of the passenger flow quickly. In almost all cases,  any anomalies detected in initial screening will trigger the need for a  person or baggage to undergo a secondary inspection, via different  methods, and typically aside from the main screening flow to confirm or  dismiss the anomaly as a threat. Technology need not be used in either  inspection stage. For example, behavioral assessment is sometimes used  to provide an initial screening. In addition, secondary inspection can be a  physical pat-down of a person or hand inspection of carry-on baggage  although explosives detection technology can also be used. Screening can  be done on 100 percent of passengers or on a subset of passengers chosen  at random or by some selection method.
Different types of bulk and trace explosives detection technology have  been developed over the years to handle both the screening of people and  the screening of carry-on baggage. Generally, equipment falls into certain  typical configurations—handheld, desktop, kit-based systems, carry-on  baggage inspection systems, explosive trace portals, AIT portals, standoff  detection systems, and explosives detection canines. Certain equipment  has been designed for the screening of people, some for the screening of  carry-on baggage, and some equipment can be used for both. (See figure  6.)
To be effective, equipment in each of these configurations is generally  evaluated across several different technical characteristics. The first  important technical characteristic of an explosives detection system is  how good it is at detecting a threat. Several different parameters are  considered to fully express a system’s ability to detect a threat. They are  used to express how often the system gets the detection right, and how  often—and in which ways—it gets the detection wrong. The system can  get the detection right when it alarms in the presence of a threat and the  percentage of times it does under a given set of conditions is called the  probability of detection.
However, other important parameters measure the percentage of times the  system gets the detection wrong. This can occur in two ways. First, the  system can alarm even though a threat is not present. This is called a false  positive and the percentage of times it occurs in a given number of trials is  called the false positive rate. It is also called the false alarm rate or  probability of false alarm. Second, the system can fail to alarm even  though a threat is present. This is called a false negative and the  percentage of times it occurs in a given number of trials is called the false  negative rate.
A second key technical characteristic for explosives detection systems is  screening throughput, which is a measure of how fast a person or item can  be processed through the system before the system is ready to accept  another person or item. Screening throughput is an important  characteristic to know because it directly impacts passenger delay, an  important consideration when using technology in passenger rail. The  higher the throughput, the less delay is imposed on passenger flow.
Other important technical characteristics to consider when assessing  applicability of explosives detection systems for use in passenger rail are  the system’s size and weight, which will impact its mobility, the physical  space needed to operate the system, and the system’s susceptibility to  harsh environmental conditions. Understanding the system’s cost is also  important.
subsections: section_title: Handheld, Desktop, and Kit Explosives Detection Systems
paragraphs: Handheld, desktop, and kit explosives detection systems are portable  systems that are designed to detect traces of explosive particles. They  have been shown to detect many explosive substances and are already  used in passenger rail environments today, generally in support of  secondary screening or in a confirmatory role when the presence of  explosives or their trace particles are suspected.
In a typical usage with handheld and desktop systems, a sample of trace  particles is collected by wiping a surface with a swab or other collection  device designed for use with the system. The sample is transferred into  the system and typically heated to vaporize the trace particles, which are  then drawn into the detector where they are analyzed for the presence of  substances indicative of explosives. The results of sample analysis are  typically displayed on a readout screen.
Handheld and desktop systems encompass a variety of detection  techniques to analyze the sample and determine if it contains particles of  explosive compounds. The various underlying techniques include ion  mobility spectrometry (IMS), amplifying fluorescent polymer (AFP),  chemiluminescence, and colorimetric. Many handheld and desktop  systems are generally based on IMS technology, a mature and well- understood method of chemical analysis. This technique consists of  ionizing the sample vapors and then measuring the mobility of the ions as  they drift in an electric field. Each sample ion possesses a unique  mobility—based on its mass, size, and shape—which allows for its  identification.
The AFP technique utilizes compounds that fluoresce when exposed to  ultraviolet light. However, the fluorescence intensity decreases in the  presence of vapors of certain nitrogen-containing explosives, such as TNT.  Detection methods based on this principle look for a decrease in intensity  that is indicative of specific explosives. AFP has been shown to have a  high level of sensitivity to TNT. The chemiluminiscence principle is based  on the detection of light emissions coming from nitro groups that are  found in many conventional military and commercial explosives such as  TNT, RDX, PETN, black powder, and smokeless powder. However,  chemiluminiscence by itself cannot identify any specific explosives  because these nitro compounds are present not only in a number of  commercial and military explosives, but also in many nonexplosive  substances such as fertilizers and some perfumes. Therefore, this  technique is often used in conjunction with other techniques, such as gas  chromatography, to positively identify specific explosives.
Kit-based explosives detection systems generally use colorimetric  techniques. In this method, the detection is based on the fact that a  specific compound, when treated by an appropriate color reagent,  produces a color that is characteristic of this compound. The sample is  taken by swiping the target object, typically with a paper, and then the  colorimetric reagents are applied by spraying or dropping them on the  paper. The operator deposits chemical reagents in a series and observes  color changes with each reagent added. This process of adding reagents is  stopped when a visible color change is observed by the operator. The  operator decides whether there are any trace explosives present by  visually matching the color change observed to a standardized sheet of  colors.
Table 1 describes some of the trace explosives detection methods  described above.
In comparative studies over the last 8 years, the Naval Explosive  Ordinance Disposal Technology Division showed that IMS-based handheld  and desktop systems are capable of detecting many conventional military  and commercial explosives that are nitrogen-based, such as TNT, PETN,  and RDX. Non-IMS based techniques such as amplifying fluorescent  polymer and chemiluminescence based techniques are able to additionally  detect ANFO, smokeless powder, and urea nitrate. However, a report  sponsored by DOD’s Technical Support Working Group shows that most  of these systems had difficulty in detecting certain other types of  explosives.
Preliminary results from an ongoing comparative study of kit-based  detection systems sponsored by the Transportation Security Laboratory  have shown that these systems can detect the presence of nitrogen when  there is sufficient quantity of explosive sample (in small-bulk or visible  amounts) available for analysis. For example, kit-based systems were able  to correctly identify the presence of nitrogen in a variety of different threat  materials. Additionally, kit-based systems have been shown to be  susceptible to false alarms when challenged with substances such as soaps  and perfumes, among others.
The open and often dirty air environment of passenger rail presents  certain operational issues for trace detection. However, durable versions  of handheld and desktop detectors are starting to appear for use in the  open and rugged field environment. This is meant to improve the  instruments’ reliability, availability, and performance in an environment  that has varying degrees of temperature, pressure, and humidity. In 2008  and 2009, both the Technical Support Working Group and the Joint  Improvised Explosive Device Defeat Organization  sponsored evaluations  of commercial ‘hardened mobile’ trace detectors, during which these  systems demonstrated the capability to detect certain types of explosives  in an open environment over a range of external temperature, pressure,  and humidity conditions.
A survey by the Transportation Security Laboratory in 2009 showed a large  number of manufacturers of handheld, desktop, and portable kit-based  devices available on the commercial market.  Although costs are a  consideration—for example, in addition to initial costs, there are routine  maintenance costs and the cost of consumables such as the swabs used  for sampling—for determining whether to make future deployments of  handheld, desktop, and kit explosives detection systems, these  technologies are already being used in the passenger rail environment and  are expected to continue to play a role there.
section_title: Carry-on Baggage Explosive Detection Systems
paragraphs: Carry-on baggage explosive detection systems are based on x-ray imaging,  a technology that has been in use for more than a century. Screening  systems incorporating the technology have been used in commercial  aviation for more than 30 years, in part, because they serve a dual purpose;  images are analyzed for guns and other weapons at the same time they are  analyzed for the presence of materials that may be explosives. Because  these images do not uniquely identify explosive materials, secondary  screening is required to positively identify the materials as explosives.
Single-energy x-ray systems are useful for detecting some bomb  components. They are, however, not as useful for the detection of  explosive material itself. Advanced techniques add multiple views, dual x- ray energies, backscatter, and computed tomography (CT) features (see  Table 2) to provide the screener with additional information to help  identify IEDs. Systems with one or more advanced techniques, multiple  views; dual energies, and backscatter, but not CT, are called advanced  technology (AT) systems to distinguish them from CT. AT systems enable  more accurate identification of explosives without the additional expense  of CT. Further, the additional information can be used to automatically  detect explosive materials. Carry-on baggage explosive detection  technology used in commercial aviation is a mature technology. The  Transportation Security Laboratory has qualified several different models  of carry-on baggage explosive detection systems manufactured by several  vendors for use in commercial aviation. Many of these systems are in use  every day at airports in the United States.
Carry-on baggage explosive detection systems are effective in detecting  IEDs that use conventional explosives when screeners interpret the  images as was demonstrated in a Transportation Security Laboratory air  cargo screening experiment where five different models of currently  fielded AT baggage explosives detection systems were used to screen all  eight categories of TSA-defined cargo.
In addition, DHS Science and Technology (S&T) Directorate provided  another comparison of screener performance to automatic detection  performance in a 2006 pilot program at the Exchange Place Station in the  Port Authority Trans-Hudson (PATH) heavy rail system. Phase I of this  pilot evaluated the effectiveness of off-the-shelf explosives detection  capabilities that were adapted from current airport checkpoint screening  technologies and procedures. The carry-on baggage explosive detection  equipment was operated in the automated threat detection mode to  minimize passenger delay. System effectiveness was tested by the use of a  red team, an adversary team that attempted to circumvent the security  measures. While the results were highly sensitive and not discussed in the  pilot program report, the false alarm rate was found to be low.
Carry-on baggage explosive detection technologies have operational issues  that limit their usefulness in passenger rail security. These systems are  used in checkpoints and their acceptability will depend upon the tolerance  for passenger delay. At checkpoints, 100 percent screening is possible up  to the throughput capacity of the screening equipment; beyond that rate,  additional screening equipment and personnel or selective (less than 100  percent) screening is required. During S&T’s screening in the PATH  system passenger rail pilot, a maximum single system throughput of 400  bags per hour was measured with carry-on baggage explosive detection  systems operating in automatic explosive detection mode at threat levels  appropriate to passenger rail, as described above. The 400 bags per hour  single system throughput had a corresponding passenger throughput of  2336 passengers per hour. With this throughput, the pilot was able to  perform 100 percent screening of large bags and computer bags (see  below) during the peak rush hour using two carry-on baggage explosive  detection systems.
Another closely related challenge associated with checkpoint screening is  passenger delay. The S&T pilot in the PATH system measured median  passenger delays of 17 seconds and 47.5 seconds respectively depending  on whether or not a passenger’s bags set off automated explosive  detection alarms. These delays can be compared to the 13 second median  time for an unscreened passenger to walk through the screening area. The  longer delay, when bags set off alarms, was caused by secondary  screening required to confirm or deny the presence of explosives.  Maximum passenger throughput was achieved when screening only bags  large enough and heavy enough to contain sufficient explosives to damage  passenger rail infrastructure. When 100 percent screening exceeded the  capacity of the system, the pilot used queue-based selection to maximize  throughput. In queue-based selection, a traffic director selects passengers  for screening as long as there is room in the queue for the screening  process. Using this procedure, the pilot was able to accommodate PATH’s  desire to keep queue lengths below five passengers.
Acquisition costs range from $25,000 to $50,000 for AT systems to more  than $500,000 for CT systems. The primary operating cost is manpower.  Operating manpower typically includes a traffic director (someone to  select passengers for screening , direct passengers to the  carry-on baggage explosive detection system, and provide instructions as  required), a secondary screener, and a maintenance person.
Structures would be needed to protect existing carry-on baggage explosive  detection systems from the challenging passenger rail environments,  which include outdoor stations that are exposed to dust and precipitation.  This is because typical carry-on baggage explosive detection systems have  hazardous parts that are not protected from foreign objects up to 1 inch in  diameter and have no protection from water intrusion.
section_title: Explosive Trace Portals
paragraphs: Explosive trace portals (ETP) are used in screening for access to buildings  and, to a limited extent, airport checkpoint screening. The operation of  these systems generally involves a screener directing an individual to the  ETP and the ETP sensing his presence and, when ready, instructing the  individual to enter. The portal then blows short puffs of air onto the  individual being screened to help displace particles and attempts to collect  these particles with a vacuum system. The particle sample is then  preconcentrated and fed into the detector for analysis. The results are  displayed to the operator as either positive or negative for the detection of  explosives. Positive results can display the detected explosives and trigger  an audible alarm.
Currently tested and deployed ETPs use IMS analytical techniques for  chemical analysis to detect traces of explosives, similar to those used for  handheld and desktop detectors. These techniques are relatively mature  but the operation of IMS-based ETPs in an open air environment, such as  that of passenger rail, is subject to interference from ambient agents, such  as moisture and contaminants, that can impact a detector’s performance  by interfering with its internal analysis process resulting in false readings.
Regardless of the detection technique used, sampling is a major issue for  trace detection. Generally, factors such as the explosives’ vapor pressure  and packaging, as well as how much contamination is present on an  individual from handling the explosive, affect the amount of material  available for sampling. Particular to trace portals, factors such as the  systems’ puffer jets and timing, clothing, the location of explosive  contamination on the body, and human variability impact the effectiveness  of sampling. For example, if the puffer jets produce too little pressure,  they have little impact in improving the trace explosive signal, while too  much pressure results in trace explosive particles becoming lost in a large  volume of air that is difficult to sample effectively. In addition, clothing  material and layering can reduce the available trace explosive signal. The  location of the explosive trace on the body also impacts the amount of  trace explosives that the system will collect.
In laboratory testing of ETPs in 2004, the Naval Explosive Ordnance  Disposal Technology Division tested three ETP systems’ basic ability to  detect trace amounts of certain explosives within the required detection  threshold when deposited on the systems’ collection sites. While the  systems consistently detected some of these explosives, they were unable  to detect others.
In addition, during laboratory testing on systems from three manufacturers  performed by the Naval Explosive Ordnance Disposal Technology Division  in 2004 and the Transportation Security Laboratory from 2004 through  2007, the systems did not meet current Naval Explosive Ordnance  Disposal Technology Division or TSA requirements.
In 10 laboratory and airport pilot tests of ETPs from three manufacturers  from 2004 through 2005, the Naval Explosive Ordnance Disposal  Technology Division and TSA also measured the systems’ throughput. In  laboratory testing, the average throughput without alarms ranged from  2.56 to 5 people per minute. During pilot testing in airports, the operational  mean throughput, which included alarms, ranged from 0.3 to 1.4 people  per minute and the operational mean screening time ranged from 15.4  seconds to 22.2 seconds. Although, they may have some applicability for  checkpoint screening in lower volume rail environments that require  passengers to queue up, the throughput and screening time of ETPs make  them impractical to use for 100 percent screening in high volume rail  stations.
An ETP system using a different analytical technique, mass spectrometry  (MS), for chemical analysis has the potential of significantly improving the  ability to distinguish explosives from environmental contaminants,  although its use in a portal configuration has not been tested in the rail  environment. DHS has, however, performed laboratory testing of two  versions of an MS-based ETP.
Other operational issues may limit their applicability in the rail  environment. GAO found that during the pilot testing in airports, for  example, the systems did not meet TSA’s reliability requirements due to  environmental conditions. This resulted in higher than expected  maintenance costs and lower than expected operational readiness time.  ETPs may have some applicability for checkpoint screening in lower  volume rail environments that require passengers to queue up such as  Amtrak, but the low throughput and long screening time of ETPs make  them impractical to use for 100 percent screening in high volume rail  stations. In addition, the large size and weight of ETPs make them difficult  to transport and deploy in stations with limited space and also impractical  for use in any random way.
section_title: Advanced Imaging Technology Portals
paragraphs: Advanced Imaging Technology (AIT) portals are used for screening people  for building access and, to an increasing extent, airport access. The  operation of these systems generally involves the individual undergoing  screening entering the AIT portal and raise his hands above his head. The  AIT portal then takes images of the individual, which are displayed to  another officer who inspects the images. The inspecting officer views the  image to determine if there are threats present. If a threat is detected, the  individual must go through further inspection to determine if the he or she  is carrying explosives.
Currently deployed AIT portals in the aviation environment use either  millimeter wave or backscatter x-ray techniques to generate an image of  a person through their clothing. While both systems generate images of  similar quality, millimeter wave has the advantage that it does not produce  ionizing radiation. Although, according to one manufacturer, its  backscatter x-ray system meets all applicable federal regulations and  standards for public exposure to ionizing radiation, systems that don’t use  ionizing radiation will likely raise fewer concerns.
An issue of particular concern to the public with AIT portals is privacy,  due to the ability of the systems to image underneath clothing (see figure  7). In order to protect passengers’ privacy, TSA policy for these systems  specifies that the officer directing passengers into the system never sees  the images. In addition, some systems offer privacy algorithms that can be  configured to blur out the face and other areas of the body or present the  image as a chalk outline. Efforts are currently underway to develop  algorithms to automate the detection of threat objects, which has the  potential to increase privacy if it eliminates the need for a human to  inspect the images.
In testing done prior to October 2009, TSA tested AIT portals from two  vendors—one using millimeter wave and the other backscatter x-ray— against detection, safety, throughput, and availability requirements for  airport checkpoint screening. Both systems met these requirements. In  addition, in 2006, TSA pilot tested an AIT portal in the rail environment to  determine the usefulness and maturity of these systems.
In 2007 and 2008, the Transportation Security Laboratory tested the  performance of AIT systems in a laboratory environment for DHS S&T.  TSA also began an operational evaluation of AIT systems in airports in  2007, which, due to privacy concerns, includes the use of privacy  algorithms. Laboratory testing included a comparison of the performance  of AIT systems against enhanced metal detectors and pat-downs;  determining the detection effectiveness of the systems for different body  concealment locations and threat types, including liquids, metallic and  nonmetallic weapons, and explosives; and measuring the systems’  throughput. The detailed results of this testing are classified so will not be  outlined in this technology assessment.
However, generally, the testing showed that there are a number of factors  that affect the performance of AIT systems, including the individual  inspecting the images for potential threats, the use and settings of privacy  algorithms, and other factors. For example, the detection performance  varied by screener. In addition, the use of privacy algorithms generally  impacts the decision time for screeners, and has other operational  considerations. The throughput of one of the AIT systems was measured  to be 40 people per hour, which was significantly lower than the S&T  requirement of 60 people per hour.
As with ETPs, AIT portals may have some applicability for checkpoint  screening in lower volume rail environments, but the low throughput, long  screening time, and other factors make them impractical to use for 100  percent screening in high volume rail stations. Another operational issue  that may limit their applicability in the rail environment is their large size  and weight that makes them difficult to transport and deploy in stations  with limited space.
section_title: Standoff Explosives Detection Systems
paragraphs: Standoff explosives detection systems are primarily differentiated from  other types of explosives detection devices by the significant physical  separation of detection equipment from the person or target being  scanned. Several different technologies have been incorporated into  standoff explosives detection systems, but those suitable for use today in a  public setting such as passenger rail are passive or active imaging systems  using typically either the millimeter wave or terahertz (THz) portion of  the electromagnetic spectrum. Radiation in these portions of the spectrum  are naturally emitted or reflected from everyday objects, including the  human body, and have the added feature that clothing is often transparent  to them. Therefore, they can be used to safely screen people for hidden  threat objects. Systems available on the market today claim to detect  person-borne objects across a range of distances.
In several laboratory and field studies since 2006 looking at passive  standoff imaging systems, organizations including Naval Explosive  Ordnance Disposal Technology Division, Transportation Security  Laboratory, S&T, and TSA have demonstrated the technology’s basic  ability, under the right conditions, to detect hidden person-borne threat  objects. Because the detection technique relies on a temperature  differential between the warmer human body and the colder threat object  next to it and not on the metallic content of the object, it also has the  potential to detect non-metallic threats. This capability gives these  standoff imaging systems a distinct advantage over walk-through metal  detectors—the conventional person screening tool—which can only detect  objects with sufficient metallic content.
DHS has also evaluated several standoff detection systems in operational  rail environments. For example, as part of Phase II of the 2006 Rail  Security Pilot looking at advanced imaging technologies, S&T found that  such systems, in general, had some ability to detect threat objects  indicative of suicide bombs on passengers and, overall, were developing  into potentially useful technologies for passenger rail. Follow-on tests in  2007 and 2009 conducted by TSA at operational passenger rail or other  mass transit locations provided further support for the technologies  potential in addressing the screening needs of these systems. In the July  2009 pilot, for instance, screening throughput for a passive millimeter  wave system was tested by TSA during rush hour at the PATH Exchange  Place subway station in New Jersey, a key entry point for commuters  entering lower Manhattan. Two systems were used with each positioned 8  to 10 meters from a group of passenger turnstiles which provided a  chokepoint for commuters entering the station. At several periods during  rush hour, the systems demonstrated the ability to scan at or near 100  percent screening—in one case, more than 900 people per hour—without  disrupting the flow of passengers.
Those pilots also demonstrated another attractive feature of these systems  important for their use in passenger rail; they can be built to be relatively  portable. For the PATH pilot, TSA broke down, moved and re-configured  multiple standoff devices four times a day. The ability for screening  systems to be deployed and easily re-deployed to another location  encourages their use for random deployment, a recommended protective  measure for mass transit systems. In addition, this allows rail operators a  way to provide screening to a much wider percentage of their system with  fewer units than it would if they had to use fixed systems, which might  prove cost prohibitive for the larger rail systems.
While promising, several factors limit the more widespread use of current  standoff detection technologies to just detection of objects carried on a  person’s body. They cannot provide a complete screening of a passenger  and their belongings. They could, however, be used in tandem with other  technologies or methods to handle accompanying articles.
Another limiting factor of current standoff technologies is the inability to  discriminate between a potential threat object and a real one. Because the  current state of the technology is based on imaging alone, explosives  material identification is generally not possible. Use of radiation in the  weaker, nonionizing millimeter wave and THz bands is attractive because  it presents no danger to humans, but it also means that there is not enough  information in the energy received by the sensor to more positively  identify the threat as explosives material, as is routinely done, for  example, by the higher energy CT systems used to screen checked baggage  in aviation. Therefore, secondary screening will often be needed to  completely resolve an alarm. In a standoff configuration, this raises  logistical and manpower issues. At a minimum, for example, since the  system is operating at a distance and passengers are not queuing up, it is  not obvious how a person showing up as a potential threat could be easily  intercepted and directed out from the normal flow of passengers.
In addition, although recent TSA testing in 2009 on an advanced standoff  system showed good performance detecting hidden threat objects— including nonmetallic objects—on moving people in controlled situations,  consistent detection under actual operating conditions in heavy passenger  volume scenarios will be challenging. The TSA tests showed good  probability of detection rates and low false alarm rates for indoors and  outdoors screening. Unlike the use of similar technology in a portal  configuration (such as AIT) where a passenger can be asked to pause, turn  around, or, for example, lift their arms to provide the sensor a better view,  in a standoff configuration passenger, movement is uncontrolled. Although  some systems allow tracking, the length of time a person can be  maintained within the required line of sight is minimal in a fast-moving,  large density crowd.
Finally, at up to several hundred thousand dollars per unit, a deployment  of standoff technology in passenger rail could be costly and manpower  intensive. Based on their operational pilots over the last several years, TSA  told us that a likely implementation for a standoff detection system at a  rail site would consist of multiple detectors, and a 3 to 4 person team  including one operator per system, an assistant, and probably two  Behavioral Detection Officers to focus special attention on persons of  interest. A good implementation would also have a canine team ready to  inspect the passenger or accompanying articles, if the system detected an  anomaly. Also, since some of the systems produce images susceptible to  the same privacy concerns as the recent deployment of AIT in airports, a  remote imaging station might also need to be configured and staffed.
section_title: Explosives Detection Canines
paragraphs: Explosives detection canines (EDC) are currently used in passenger rail  systems for both random screening of passengers and their belongings and  as a deterrent to criminal and terrorist activity. EDCs are considered a  mature technology and are being used by all of the passenger rail  operators with whom we spoke or that attended our expert panel. These  operators also viewed canines as the most effective method currently  available for detecting explosives in the rail environment because of their  detection capability as well as the deterrent effect that they provide. More  specifically, operators noted EDCs’ ability to rapidly move to various  locations throughout a rail system, their minimum impact on passenger  flow and rail operations, and their ability to detect explosives they are  trained to detect. Operators and experts on our panel also noted that  canines are generally accepted by members of the public that use these  systems. In addition to passenger rail operators, canines have been  deployed by federal agencies such as the U.S. Secret Service; Bureau of  Alcohol, Tobacco, Firearms, and Explosives (ATF); and U.S. Customs and  Border Protection. While the use of canines is mature, both the  government, through DHS S&T, as well as academia, are conducting  ongoing research on the limits of canine detection.
While the mechanism of how canines detect explosives through their  sense of smell is not well understood, there are several certification  programs to validate the canines’ ability to detect explosives, which  include specifying standards for explosives detection. These standards  vary based on which entity is certifying the canine. A guiding document on  the training of canines is the Scientific Working Group on Dog and  Orthogonal Detectors Guidelines that specifies recommended best  practices for canine explosives detection. These standards call for an EDC  to detect explosives a certain percent of the time and a probability of false  alarms less than a certain rate. Certifying entities, however, may have  more stringent standards. For example, ATF requires that its canines  detect all explosives that are presented to them, and have limited false  alarms in its tests. TSA requires that their certified canines find a specified  percent of explosives in a variety of scenarios, such as onboard an aircraft,  mass transit rail, and mass transit buses. Homeland Security Presidential  Directive-19 tasks the Attorney General, in coordination with DHS and  other agencies, with assessing the effectiveness of, and, as necessary,  making recommendations for improving federal government training and  education initiatives related to explosive attack detection, including  canine training and performance standards. According to ATF officials,  TSA, in coordination with ATF, is developing standards for EDCs, which  are nearly complete and are similar to the standards that ATF uses.
EDCs have a limited period of endurance at which they can maintain  effective detection capabilities. According to ATF officials and other  experts that attended our panel, canines can typically operate between 20  and 45 minutes before requiring a break with a total of 3 to 4 hours of time  spent detecting per day. Additionally, members of our expert panel told us  that aspects of the rail environment such as dirt, cleaning chemicals, and  metal fragments from trains, may reduce canines’ optimum operating time  in this environment. As a result, one rail operator told us that their EDCs  are stored in the back of police cars throughout the day unless they are  needed and are not available for use as a deterrent. TSA advocates using  explosive detection canines on patrols as visible deterrents in an effort to  reduce crime and prevent the introduction of explosives into the rail  environment.
Canines have a history of being trained to detect items and in recent years  have been trained to detect, among other things, explosives, fire  accelerants used in arson investigations, and drugs. While training  methods differ among canine training schools, these methods typically  train canines by rewarding them for locating certain items. Rewards  include toys, a food treat, or the canine’s food itself. In turn, these canines  are trained to alert their handlers if they detect an item of interest, usually  by sitting down next to the item. EDCs used in rail are generally deployed  to screen passenger baggage, either on a primary basis by inspecting  baggage as passengers enter a system or on a secondary basis to screen an  item of interest, such as an unattended package. Additionally, EDCs are to  receive training on a regular basis to ensure that they are capable of  detecting explosives. Recurrent training requirements vary based on the  training method used with the canine. For instance, one training regime  we reviewed calls for 4 hours per week of recurrent training for EDCs,  while other training regimes, such as those used by ATF, require daily  training. The amount of recurrent training necessary for EDCs has not  been determined according to the experts we spoke with, but they agree  that the training is necessary to ensure the canine accurately detects  explosives. As such, passenger rail operators who employ EDCs are to  incorporate the training regime specified by the training method used to  produce the EDC to ensure the canine operates effectively. Additionally,  TSA and ATF both require their trained EDCs to be recertified on an  annual basis whereby the canine and handler must demonstrate that they  can detect explosives and meet required performance standards.
The quality of an EDC’s search for explosives is dependent on the handler  correctly interpreting behavioral changes of the canine. As the canine is  capable of giving a positive or negative response as to the presence of an  explosive odor emanating from an item, the handler must interpret the  canine’s response and respond appropriately in keeping with a pre- determined concept of operations because the canine cannot indicate the  type of explosive it has detected. Moreover, according to ATF officials, a  canine is only capable of detecting the explosives it has been trained to  detect and there are tens of thousands of explosive compounds. To  address this issue, ATF separates explosives into six categories with  similar characteristics that the canines are trained and required to identify.
According to TSA, the total initial cost to acquire and train an EDC and  handler is about $31,000. In addition, there are also ongoing maintenance  costs including food, veterinary services, and other maintenance expenses,  as well as the ongoing expense of the handler’s salary. TSGP grant funding  can often be used to offset the initial acquisition cost of the canine, but  cannot typically be used to pay for ongoing maintenance throughout the  canines’ duty life. According to ATF officials, an EDC typically has an  operational life of about 7 years, having completed training around age 2  and entering retirement at age 9.
Vapor Wake Canines are an emerging use of EDCs that may be applicable  to the passenger rail environment. Vapor Wake Canines differ from more  traditional EDCs in that the canine does not directly sniff individual  passengers and their belongings and instead the canine may remain in a  stationary location sniffing multiple passengers as they pass by the canine,  thus allowing more passengers and their belongings to be screened. These  canines are trained to alert if they detect any explosives in the air and  follow the explosive to its source. Vapor Wake Canines were piloted by  DHS S&T in 2006 in the Metropolitan Atlanta Rapid Transit Authority with  generally positive results. Specifically, these canines were able to detect  explosives under the concept of operations developed by DHS S&T. DHS  S&T officials told us that they will soon begin additional research on  Vapor Wake Canines to determine their probability of detection and to  better understand factors behind their performance.
section_title: Limitations in Available Explosives Detection Technologies Restrict Their More Widespread or More Effective Use in Passenger Rail
paragraphs: The ability of explosives detection technologies to help protect the  passenger rail environment depends both upon their detection  performance and how effectively the technologies can be deployed in that  environment. Detection performance varies across the different  technologies with more established technologies such as handheld,  desktop, kit-based trace detection systems, x-ray imaging systems, and  canines having demonstrated good performance against many  conventional explosives threats while newer technologies such as ETPs,  AIT, and standoff detection systems are in various stages of maturity.  However, all of the technologies face key challenges, and most will  struggle in passenger rail stations to screen passengers without undue  delays. Important characteristics of the technologies such as screening  throughput, mobility, and durability, as well as physical space constraints  in rail stations may limit deployment options for explosives detection  technologies in passenger rail.
subsections: section_title: Detection Performance Varies Across the Different Explosives Detection Technologies and Challenges Exist in Detection of HMEs
paragraphs: Certain explosives detection technologies have demonstrated good  detection performance against conventional explosives. Explosives  detection canines, for example, are certified by several organizations as  being able to detect a wide variety of conventional explosives for which  they have been trained. In addition, some of the analytical trace detection  methods are mature laboratory techniques that—within their individual  design constraints—have been shown to be capable of consistent  detection of many conventional explosives and their components when  used in handheld, desktop, and kit-based systems. In many cases, this is  because they have been designed specifically to focus on specific  characteristics of nitro-based conventional explosives. Similarly, the more  mature bulk detection techniques—carry-on baggage x-ray systems, for  example—have been widely used for many years and, when used by  trained operators, have shown good detection performance.
However, some of the newer detection technologies—ETPs, AIT, and  standoff detection systems, for example—are in varying stages of maturity  and more extensive testing would be required to determine their likely  performance if deployed in passenger rail. For example, ETPs performed  poorly in laboratory testing even though those devices incorporated  mature analytical detection techniques. In this case, the variation in  performance might be the result of how those techniques are integrated by  specific manufacturers into a portal configuration. AIT is currently being  deployed in airports nationwide, and laboratory testing has shown it has  some ability to detect explosives. While standoff detection systems have  demonstrated good performance detecting hidden threat objects on  people in controlled testing, consistent detection under actual operating  conditions in heavy passenger volume scenarios will be challenging.
With all the technologies, certain factors underlie their ability to achieve  adequate performance and often these depend on the human operator. For  example, in a trace detection system the human operator plays a key part  in preparing the sample and delivering it to the trace detection machine. In  addition, trace detection is an indirect method of detection, relying on the  presence of trace signatures that may, in fact, not exist or exist in  insufficient quantities to be detected even though the threat object is  present, or are present in the absence of a threat object.
Similarly, image based detection schemes are all dependent on successful  image interpretation. Human operator image interpretation is a difficult  task and performance is largely a function of adequate and persistent  training. To help address this issue, DHS has initiated efforts looking at  enhancing automated image processing algorithms to provide for better  detection and lower false alarm rates. As part of this, DHS is creating a  database of raw image data from commercially available systems—for  example, x-ray and millimeter wave image data—which can be made  available to researchers to help them develop better automated detection  algorithms to improve processing across a range of imaging technologies  including carry-on baggage x-ray technologies such as AT-based systems,  AIT, and some of the standoff detection technologies. With the goal of  increasing the probability of detection and reducing the number of false  alarms these systems generate when operating in automated mode, such  enhancements could help with the challenge of screening large volumes of  people by increasing system throughput. While an outgrowth of research  and development to support aviation security, this could benefit the use of  imaging technologies in passenger rail settings as well.
Finally, adequate detection performance of explosives detection  technologies can depend on other factors, such as maintenance, system  calibration, and proper setup. For example, performance can be affected  by the operator’s preferences regarding sensitivity of the equipment. With  many of the technologies there are tradeoffs that can be made between the  sensitivity of the device and the operator’s tolerance for false alarms. In  cases where a trace detector is highly sensitive to contaminants in the air,  for instance, decreasing the sensitivity may reduce the number of false  alarms but will also increase the possibility for missed detections.
One of the issues in implementing explosives detection technologies  effectively in passenger rail is in identifying the explosive materials and  amounts that constitute the threat to that environment. While  requirements and standards for explosives threat amounts and detection  levels, for example, have been defined for the aviation environment and  for DOD’s counter IED mission, threat amounts have not been determined  for rail for either the conventional explosives threat or the threat from  HMEs. As a result, in general, detection performance has been measured  against threats levels defined for other environments.
section_title: Screening Throughput, Mobility, and Other Characteristics of Explosives Detection Technologies Could Limit Deployment Options in Passenger Rail
paragraphs: Because passenger volumes and timeliness expectations vary across the  different rail systems including heavy rail and commuter or light rail,  different methods of selecting and screening passengers are possible.  Although passenger volumes in the heavier trafficked rail stations may  preclude 100 percent screening of passengers in an overly intrusive way,  lighter volume stations may allow for such intrusive screening if an  adequate screening throughput speed can be maintained. Decisions  regarding screening modes will vary by systems, stations, and the  tolerance for passenger delay.
Two important system characteristics when considering the use of  explosives detection technologies in passenger rail are screening  throughput and system mobility. The higher the throughput, the less delay  is imposed on passenger flow. The more portable a detection system is,  the more it lends itself for use in random deployment, a known deterrent  and cost effective option for rail operators.
Screening throughput and system mobility varied across the different  explosives detection technologies we examined, but many had screening  times that would be difficult to accommodate in situations with heavy  passenger volume. In airport security checkpoints, for example, using  similar equipment and working toward a goal of 10 minute or less wait  times, the TSA staffing allocation model for screening operations requires  individual screening lanes to be able to process 200 passengers per hour.   However, during the 2006 S&T pilot testing in PATH, passenger flow rates  on the order of 4,000 passengers per hour was measured during the  afternoon rush at just the main entrance turnstiles at one station. Even  under TSA’s aviation wait time goal this would require the purchase,  staffing, and physical space for 20 screening lanes.
These technologies, however, might be considered for use in lower volume  rail stations, for example, or in other areas of passenger rail where  passenger queues could be supported without unduly impacting passenger  flow. However, they are generally large, bulky and not easily moved from  place to place and therefore impractical for use in any highly mobile way.
In general, most passenger rail operators that have deployed explosives  detection technologies have done so on a less intrusive basis, using, for  example, mobile explosives detection canine teams as a deterrent in  stations or, alternatively, setting up temporary, portable stations for the  screening of selected passengers who are pulled out of the normal  passenger flow randomly, via some selection method, or as a result of  behavioral cues. In this mode, for example, they have used handheld  detectors for primary screening.
Standoff detection systems, which minimize the impact of screening on  passenger flow, are the only explosives detection technology that  currently could be considered for helping to address the 100 percent  screening scenario at heavy volume stations, generally, for passenger rail.  As noted, some of these systems demonstrated the ability to scan at or  near 100 percent of passengers even in heavy rail stations for periods of  time. In addition, many are portable and are designed so that system  installations could be shifted from site to site. However, while attractive  from a throughput point of view, standoff systems are developing in terms  of their detection performance and general concept of operations.
In addition to limitations imposed by the technologies, rail stations  themselves have constraints that will influence the applicability of certain  technology for certain purposes. These include environmental issues, such  as the relatively high level of contaminants found in passenger rail  environments like steel dust and soot that can disrupt the operation of  sensitive equipment, and raise the potential for false alarms, and the lack  of controlled temperature and humidity levels in many stations and the  potential for extremes of those levels in outdoor stations. Some DOD  research and development efforts are looking at hardened versions of  some explosives detection technologies.
The general openness of many rail stations is another important  consideration in deciding on the use of explosives detection technologies  in rail. In commuter or light rail systems, for example, many stations may  be unmanned, outdoor platforms without barriers between pubic areas  and the train and with few natural locations to place technologies to be  able to screen passengers. With limited existing chokepoints,  implementation of certain technologies may require station infrastructure  modifications to aid in funneling passengers for screening.
Finally, physical space constraints in many stations are an important  consideration. For example, many rail stations have limited space in which  to install large equipment, accommodate any passenger queues that might  build up, or add multiple screening lanes as a way of dealing with long  lines. Further, while standoff detection technologies are more able to deal  with heavy passenger volumes and do not necessarily have a large physical  footprint, they do require several to tens of meters of open, line of sight  spacing between sensor and passengers for effective operation.
section_title: Several Overarching Operational and Policy Factors Could Impact the Role of Explosives Detection Technologies in the Passenger Rail Environment
paragraphs: In addition to how well technologies work in detecting explosives and  their applicability in the passenger rail environment, there are several  overarching operational and policy considerations impacting the role that  these technologies can play in securing the passenger rail environment,  such as who is paying for them and what to do when they apparently  detect explosives. Even if a technology works in the passenger rail  environment, our work, in consultation with rail experts, identified several  critical operational and policy factors that arise when these technologies  are being considered for deployment. Specifically, 1) the roles and  responsibilities of multiple federal and local stakeholders could impact  how explosives detection technologies are funded and implemented in  passenger rail; 2) implementation of technology or any security investment  could be undertaken in accordance with risk management principles, to  ensure limited security funding is allocated to those areas at greatest risk;  3) explosives detection technologies are one component of a layered  approach to security, where multiple security measures combine to form  the overall security environment; 4) a well-defined and designed concept  of operations for the use of these technologies is important to ensure that  they work effectively in the rail environment; and 5) cost and potential  legal implications are important policy considerations when determining  whether and how to use these technologies.
subsections: section_title: The Roles and Responsibilities of Multiple Federal and Local Stakeholders Could Impact How Explosives Detection Technologies are Funded and Implemented in Passenger Rail
paragraphs: Although there is a shared responsibility for securing the passenger rail  environment, the federal government and rail operators have differing  roles, which could complicate decisions to fund and implement  technologies. More specifically, while passenger rail operators are  responsible for the day to day security measures in their stations,  including funding them, they utilize federal grant funding to supplement  their security budgets. While federal grant funding for security has  increased in recent years, decision making for funding these measures,  including technology, is likely to continue to be shared between the rail  operators and the federal government moving forward. In addition, as  federal agencies implement their own rail security measures and  operations, which could include the use of explosives detection  technology, decisions of how to implement and coordinate these measures  will likely be shared with operators.
Regarding the federal role, TSA defines and implements federal policies  and actions for securing passenger rail systems in their role as the lead  federal agency responsible for transportation security. TSA’s strategy for  securing passenger rail is identified in the Mass Transit Modal Annex to  the Transportation Systems- Sector Specific Plan, including its role in  developing and procuring technologies for securing rail systems. To date,  TSA’s primary approach to securing passenger rail, defined in the Modal  Annex, has been to assess the risk facing rail systems, develop security  guidance for rail operators, and to provide funding to operators to make  security improvements to their systems, including the purchase of security  technologies. Specifically, TSA’s stated objectives for using technology in  passenger rail is to bolster the use of technologies to screen passengers  and their bags on a random basis in partnership with rail operators.  According to the Modal Annex, these objectives are to be achieved  through the use of explosives detection technology to screen passengers  during TSA Visible Intermodal Prevention and Response (VIPR)  operations and screening programs introduced by passenger rail operators  themselves. In addition, through its National Explosives Detection  Canine Team Program (NEDCTP), TSA procures, trains, and certifies  explosives detection canine teams and provides training and the canines  to passenger rail operators.
TSA also supports the use of technology by providing funding to rail  operators to purchase screening technologies and train their employees  through TSGP. To date, TSGP has provided funding for various security- related technologies; including handheld explosive trace detection  equipment, closed-circuit television, intrusion detection devices, and  others. In June 2009, we reported that the TSGP faces a number of  challenges, such as lack of clear roles and responsibilities in the program  and delays in approving projects and making funds available to operators,  and as of February 2009, of the $755 million that had been awarded by  TSGP for fiscal years 2006 through 2008, approximately $334 million had  been made available to transit agencies, and transit agencies had spent  about $21 million. We further reported that these delays were caused  largely by TSA’s lengthy cooperative agreement process with transit  agencies, a backlog in required environmental reviews, and delays in  receiving disbursement approvals from FEMA. As such, rail operators  have spent a small percentage of the resources available to fund security  investments. We recommended that DHS establish and communicate to  rail operators time frames for releasing funds after the projects receive  approval from TSA. DHS agreed with this recommendation and indicated  that it would establish and communicate timeframes for releasing funds to  TSGP grantees and try to release funds shortly after they have received all  required documentation from grant recipients.
Additionally, in a March 2010 report, the administration’s Surface  Transportation Security Priority Assessment recommended that TSA  adopt a multi-year, multi-phase approach for grant funding based on a  long-term strategy for transportation security. This approach calls for  segmenting larger projects into smaller components to both complete the  projects quicker and also to provide strategic planning for future grant  funding needs and provide closer alignment of federal and stakeholder  long-term priorities. Moreover, during our expert panel, rail operators  stated that they would prefer the federal government to procure and  provide security technologies to them, instead of providing cash awards to  directly procure the technologies by the operators. These operators  indicated that their local procurement regulations can often make the  process of procuring security technologies slow and cumbersome.
In addition to providing funding for technology, the Modal Annex also  identifies TSA’s role in providing resources for research, development,  testing, and evaluation of technology. TSA, like other DHS components, is  responsible for articulating the technology needs of all transportation  sector stakeholders—including passenger rail operators—to DHS S&T for  development. Although TSA and DHS have worked to develop some  security technologies specific to passenger rail systems, technologies that  it has pursued could work across different transportation modes,  including aviation, maritime, mass transit, and passenger rail. TSA officials  told us that they look for opportunities to take advantage of technologies  in transportation modes other than those for which they were originally  developed. However, the TSA officials indicated that certain  characteristics of passenger rail may not allow the deployment of  technologies developed for other modes such as aviation.
In addition to its work with S&T, TSA has commissioned its own research  efforts, including pilot programs designed to test existing explosives  detection equipment in the rail environment and the use of standoff  technologies in the passenger rail environment. Additionally, the  administration recommended in its March 2010 report that TSA, DHS S&T,  and other agencies directly involve rail operators in setting surface  transportation research and development priorities.
TSA also provides technological information to rail operators through the  Public Transit Portal of the Homeland Security Information Network  (HSIN) and maintains a Qualified Products List (QPL) of technologies  that have been qualified for use in aviation. As we reported in June 2009,  the information on HSIN is in an early state of development and contains  limited information that would be useful to rail operators. For example,  for a given security technology, TSA’s list of technologies provides a  categorical definition (such as video motion analysis), a subcategory (such  as day or night camera), and the names of products within those  categories. We also reported that the list on HSIN neither provides nor  indicates how rail operators can obtain information beyond the product’s  name and function and does not provide information on the product’s  capabilities, maintenance, ease of use, and suitability in a rail  environment. We recommended that TSA explore the feasibility of  expanding the security technology information in HSIN, including adding  information on cost, maintenance, and other information to support  passenger rail agencies’ purchases and deployment of these technologies.  TSA concurred with this recommendation and stated that it would provide  information on HSIN about specifications, performance criteria, and  evaluations of security technologies used in or adaptable to the passenger  rail environment. In January 2010, TSA officials told us that they were still  planning to provide this information on the HSIN some time in 2010, but  had not done so yet.
TSA officials told us that in addition to the QPL for aviation there is  another list that is administered by FEMA called the Authorized  Equipment List, which provides a list of technologies for which TSGP  grant recipients can use grant funding. According to TSA officials, the  Authorized Equipment List is available on HSIN and there is one  explosives detection technology on the list—a handheld explosive trace  detector. Passenger rail operators that attended our expert panel stated  that they would like TSA to pursue research more directly related to rail  and provide additional information on which technologies are best for use  in rail, including a list of “approved” or recommended technologies. TSA  officials told us that they are currently developing minimum standards for  technologies for modes of transportation other than aviation, but did not  provide a time frame for completing this effort. Once these standards are  developed they envision adding categories for other modes of  transportation-—such as rail-—to the QPL. Additionally, the  administration’s Surface Transportation Security Priority Assessment  report from this year recommended that TSA along with DHS S&T  establish a fee-based, centrally managed “clearing house” to validate new  privately developed security technologies that meet federal standards.
In contrast to the federal role, passenger rail operators and local  government stakeholders are responsible for the day-to-day security of rail  systems, including the purchase, installation, and operation of any  explosives detection technologies. As such, operators consider their own  unique security and operational needs when deciding whether and to what  extent to use these technologies. While the operators have responsibility  for securing their systems, the operators that attended our panel  expressed to us that their limited resources often limit their ability to  directly invest in security, including technology, and instead they look to  the federal government to provide financial assistance. For example, rail  operators that we spoke to and that attended our expert panel noted that  they often do not collect sufficient revenue from their fares to cover  operational expenses.
In June 2009, we reported that while the majority of rail operator actions  to secure passenger rail have been taken on a voluntary basis, the pending  9/11 Commission Act regulations outline a new approach that sets forth  mandatory requirements, such as, among others, requirements for  employee training, vulnerability assessments, and security plans, the  implementation of which may create challenges for TSA and industry  stakeholders. In general, TSA has a collaborative approach in  encouraging passenger rail systems to voluntarily participate and address  security gaps. We also reported that with TSA’s pending issuance of  regulations required by the 9/11 Commission Act, TSA will fundamentally  shift this approach, and establish new regulatory requirements for  passenger rail security. TSA officials stated that they do not see the 9/11  Commission Act requirements impacting TSA’s current role as it relates to  technologies in the passenger rail environments. Because of the unique  characteristics of the rail environment and the fact that the 9/11  Commission Act does not impose specific requirements related to  technologies, TSA officials stated that the agency’s role will continue to be  to assist rail operators in conducting random deployments of explosives  detection technologies and inspections, as stated in the Modal Annex.
section_title: Risk Management Could be Used to Effectively Guide the Decision to Fund or Implement Explosives Detection Technologies
paragraphs: As passenger rail operators consider the use of explosives detection  technologies, it is not only important to select technologies capable of  detecting explosives and that can be used in the passenger rail  environment, but it is also important to select technologies that will  address identified risks. We have recommended that a risk management  approach be used to guide the investment of security funding, particularly  for passenger rail systems, where security funding and rail operator  budgets are limited. As such, the decision as to whether or not to deploy  explosives detection technologies should be made consistent with a risk  management framework to ensure that limited security budgets are  expended to address the greatest risks. We reported in June 2009 that  officials from 26 of 30 transit and passenger rail systems we visited stated  that they had conducted their own assessments of their systems, including  risk assessments. Additionally, Amtrak officials stated that they conducted  a risk assessment of all of their systems. As part of the assessment,  Amtrak contracted with a private consulting firm to provide a scientific  basis for identifying critical points at stations that might be vulnerable to  IED attacks or that are structurally weak. We also reported that other  transit agencies indicated that they have received assistance in the form of  either guidance or risk assessments from federal and industry  stakeholders. For example, FTA provided on-site technical assistance to  the nation’s 50 largest transit agencies (i.e., those transit agencies with the  highest ridership) on how to conduct threat and vulnerability assessments,  among other technical assistance needs, through its Security and  Emergency Management Technical Assistance Program (SEMTAP).  According to FTA officials, although FTA continues providing technical  assistance to transit agencies, the on-site SEMTAP program concluded in  July 2006. Furthermore, FTA officials stated that on-site technical  assistance was transferred to TSA when TSA became the lead agency on  security matters for passenger rail.
In addition, multiple federal agencies recommend the use of risk based  principles in assessing risk and making investment decisions. DHS’s  National Infrastructure Protection Plan states that implementing  protective programs based on risk assessment and prioritization enables  DHS, sector-specific agencies, and other security partners to enhance  current critical infrastructure and key resources protection programs and  develop new programs where they will offer the greatest benefit. Further,  TSA’s Modal Annex advocates using risk-based principles to secure  passenger rail systems and we have previously reported that TSA has used  various threat, vulnerability, and consequence assessments to inform its  security strategy for passenger rail. In June 2009, we reported that TSA  had not completed a risk assessment of the entire passenger rail system  and recommended that, by doing so, TSA would be able to better prioritize  risks as well as more confidently assure that its programs are directed  toward the highest priority risks. TSA concurred with this  recommendation and stated that it is developing a Transportation Systems  Security Risk Assessment that aims to provide TSA with a comprehensive  risk assessment for use in passenger rail. To this end, TSA told us that it  has developed a Transportation Systems Sector Risk Assessment report,  which is to evaluate threat, vulnerability, and consequence in more than  200 terrorist attack scenarios on passenger rail. Moreover, TSA also  indicated that they are developing and fielding a risk assessment capability  focused on individual passenger rail agencies. This effort includes, among  other things, a Baseline Assessment for Security Enhancement for rail  operators, a Mass Transit Risk Assessment, and an Under Water Tunnel  Assessment. Rail operators with whom we spoke or who attended our  expert panel noted the importance of using risk management practices to  allocate limited resources.
section_title: Explosives Detection Technologies are One Component of a Layered Approach to Security
paragraphs: TSA’s Modal Annex calls for a flexible, layered, and unpredictable  approach to securing passenger rail, while maintaining an efficient flow of  passengers and encouraging the expanded use of the nations’ rail systems.  Expanding the use of explosives detection technology is one of the layers  of security identified by the Modal Annex. When considering whether to  fund or implement explosives detection technologies, it will be important  for policymakers to consider how explosives detection technology would  complement other layers of security, the impacts on other layers of  security, and the security benefits that would be achieved. For example,  one rail operator who attended our expert panel told us that they used  deployments of explosives detection technologies along with customer  awareness campaigns and CCTV as layers of security in their security  posture. In addition to explosives detection technology, other layers of  security that rail operators have used or are considering using to secure  passenger rail include:    Customer awareness campaigns. Rail operators use signage and  announcements to encourage riders to alert train staff if they observe  suspicious packages, persons, or behavior. We have previously reported  that of the 32 rail operators we interviewed, 30 had implemented a  customer awareness program or made enhancements to an existing  program.  Increased number and visibility of security personnel. Of the 32 rail  operators we previously interviewed, 23 had increased the number of  security personnel they utilized since September 11, 2001, to provide  security throughout their system or had taken steps to increase the  visibility of their security personnel. Further, these operators stated that  increasing the visibility of security is as important as increasing the  number of personnel. For example, several U.S. rail operators we spoke  with had instituted policies such as requiring their security staff, wearing  brightly colored vests, to patrol trains or stations more frequently, so they  are more visible to customers and potential terrorists or criminals. These  policies make it easier for customers to contact security personnel in an  emergency or potential emergency.
Employee training. All 32 of the rail operators we previously interviewed  had provided security training to their staff, which largely consisted of  ways to identify suspicious items and persons and how to respond to  events.
CCTV and video analytics. As we previously reported, 29 of 32 U.S. rail  operators had implemented some form of CCTV to monitor their stations,  yards, or trains. Some rail operators have installed “smart” cameras which  make use of video analytics to alert security personnel when suspicious  activity occurs, such as if a passenger left a bag in a certain location or if a  person entered a restricted area. According to one passenger rail operator  we spoke with, this technology was relatively inexpensive and not difficult  to implement. Several other operators stated they were interested in  exploring this technology.
Rail system design and configuration. In an effort to reduce vulnerabilities  to terrorist attack and increase overall security, passenger rail operators  are incorporating security features into the design of new and existing rail  infrastructure, primarily rail stations. For example, of the 32 rail operators  we previously interviewed, 22 of them had removed their conventional  trash bins entirely, or replaced them with transparent or bomb-resistant  trash bins. Of 32 rail operators we previously interviewed, 22 had stated  they were incorporating security into the design of new or existing rail  infrastructure.
section_title: A Concept of Operations For Explosives Detection Technologies Could Enable Passenger Rail Operators to Better Balance Security with the Movement of Passengers
paragraphs: In deploying explosives detection technologies, it is important to develop a  concept of operations (CONOPS) for both using these technologies to  screen passengers and their belongings and for responding to identified  threats. This CONOPS for passenger rail would include specific plans to  respond to threats without unacceptable impacts on the flow of  passengers through the system. There are multiple components of a  CONOPS. First, operators identify likely threats to rail systems and choose  layers of security to mitigate these threats. Since each rail system in the  United States faces different risks, rail systems perform their own risk  assessment in consultation with federal partners to identify their risks.  Using the results of the risk assessment, each system crafts a strategy to  respond to the threat and to mitigate the risks by acquiring different layers  of security. Rail systems typically make use of multiple security layers— which may or may not include the use of an explosives detection  technology component—based on the risks each system faces.
The CONOPS is a plan to respond to threats identified by one of the layers  of security. Developing a CONOPS for responding to explosives detection  technology is challenging because of the potential for false alarms. For  example, two rail operators with whom we spoke and that were using  explosives detection technologies to screen passengers and their  belongings stated that a CONOPS was critical for ensuring that actions  taken in response to an alarm are appropriate and are followed correctly.  For example, should the person be questioned or searched further or  should the person be moved to another location on the chance that the  threat is real. These are questions that would be answered in developing a  CONOPS and before implementing explosives detection technology in the  passenger rail environment. Two of the rail operators and one of the  experts that attended our panel also expressed concern about the  potential for false alarms when using explosives detection technologies  and the potential impacts on rail operations. For example, operators were  concerned about a false alarm stopping service. As a result, it is important  to carefully consider the CONOPS of using a particular technology, such  as how to respond to false alarms, in addition to the security benefits  before implementation. For instance, one major rail operator’s CONOPS  involves using handheld explosives detection technology to screen  passengers’ baggage randomly by a law enforcement officer. The  frequency in which bags are selected is determined in advance by  someone other than the law enforcement officer—such as a supervisor— based on a number of factors such as the number of passengers entering a  station and resources available for screening. The baggage is then  screened by the officer with the explosives detection equipment; if there is  no alarm, the passenger is free to continue. Should the bag alarm, the  officer then questions the passenger to determine the source of the alarm  and, if necessary, takes action to respond to a threat.
section_title: Costs, Potential Legal Implications, and Policy Concerns, such as Privacy and Health, Are Important Considerations When Making Decisions about Explosives Detection Technologies in the Passenger Rail Environment
paragraphs: Cost is an important consideration for rail system security investments, as  all operators have limited resources to devote to security. For example, all  of the rail operators that we spoke with and that attended our expert panel  expressed the view that obtaining funds for security priorities is  challenging. Nearly all domestic rail systems operate at a deficit in which  their revenues from operations do not cover their total cost of operations.  An official from the industry association representing passenger rail and  mass transit systems that attended our expert panel stated that when it  comes to security investments, security often becomes less of a priority  than operational investments as they often operate with budgets deficits.  In addition, another rail operator that attended our expert panel raised  concern that TSGP often will not provide funding for ongoing maintenance  of capital purchases, additional staff needed to deploy these technologies,  and disposable items required to operate the technology, such as swabs  for explosive trace detection devices. For example, while rail operators  can use TSGP grant funds to purchase explosives detection equipment,  funding for the operation and maintenance of this technology is only  provided for a 36 month period. One major rail operator that attended our  expert panel stated that the cost of deploying a random baggage check  with a handheld explosive trace detector costs between $700 and $1,000  per hour, including the costs of staffs’ salaries and disposable items. Given  the cost of operating and maintaining these security technologies, it would  be important for policymakers to consider all associated costs of these  technologies before implementing new security measures or encouraging  their use.
Legal implications with regard to constitutional and tort law would also be  important for passenger rail operators to consider when determining  whether and how explosives detection technologies are applied in the  passenger rail environment. The Fourth Amendment of the U.S.  Constitution protects individuals against unreasonable governmental  searches, and state constitutional law may provide additional protections  against searches. In recent years, federal courts have heard several  challenges to new passenger inspection programs implemented in  passenger rail environments. In these cases, in order to assess the  constitutionality of the programs, the courts considered factors such as  the intrusiveness of the searches, the government interest in the program,  and the effectiveness of the program. In addition to constitutional  concerns, taking actions to mitigate potential tort liability is another  important consideration for rail operators. For example, state law may  allow individuals to bring tort claims against transit agencies, such as  claims related to invasion of privacy and health hazards posed by scanning  equipment. Also, operators using explosives detection canines should be  conscious of potential claims related to dog bites.
There are also privacy considerations associated with subjecting  passengers to certain types of screening technologies. Because explosives  detection technologies generally do not collect personally identifiable  information, they pose fewer privacy concerns than other screening  techniques may. However, a number of advocacy groups have raised  concerns about the use of AITs which produce an image of a person  without clothing. To protect passengers’ privacy, however, ways have  been introduced to blur the passengers’ images with privacy settings.
Concerns also exist about the impact that certain technologies could have  on the health of passengers. For example, certain types of explosives  detection screening equipment may expose individuals to mild radiation.  Specifically, technologies such as backscatter x-ray AIT expose the  passenger to minute amounts of radiation. While this radiation exposure is  smaller than the radiation a person receives by a normal medical x-ray, the  public may have concerns about being exposed to any radiation or may  misjudge the amount of radiation they receive. For example, according to  TSA, a person would require more than 1,000 backscatter scans in a year  to reach the effective dose equal to one standard chest x-ray. Additionally,  some forms of IMS technology make use of radiation in their operation  and some people may be concerned with having any radiation source in a  rail network.
Finally, some passenger rail systems operate across multiple city, county,  and other jurisdictions and must coordinate with local governments and  law enforcement across these areas. For example, the Washington  Metropolitan Area Transit Authority was established by an interstate  compact between Maryland, Virginia, and the District of Columbia. The  authority has its own police force and must coordinate with not only the  police force of the District of Columbia, but also the surrounding  communities through which its trains pass. This pattern is common across  the country where public transportation systems cross state and local  boundaries. As such, the use of explosives detection equipment  throughout these networks involves coordination across many levels of  government and may potentially invoke the laws of multiple jurisdictions  and come under the scrutiny of different governments.
section_title: Concluding Observations
paragraphs: Securing passenger rail systems is a daunting challenge for several  reasons, including the open nature of these systems and the relative ease  and the number of locations in which these systems can be accessed by  those wishing to cause harm. While there are some explosives detection  technologies available or currently in development that could be used to  help secure passenger rail, there are several technical, operational, and  policy factors that are important to consider when determining the role  that these technologies can play in passenger rail security. There are  various stakeholders responsible for securing passenger rail systems and  all may need to be involved when making decisions to fund, implement,  and operate explosives detection technologies. It is also important that the  need for explosives detection technologies be based on a consideration of  the risks posed by the threat of an explosives attack on passenger rail  systems. Such a risk assessment would help define the detection needs,  including what explosives materials need to be detected and in what  quantities.
Explosives detection technologies are just one of many layers of security  and cannot, by themselves, secure passenger rail systems. While  explosives detection technologies can play a role in securing passenger  rail systems, certain aspects of these technologies will likely limit their  immediate use. All of the technologies face key challenges, including the  ability to screen passengers without undue delays. In some cases, the  ability to detect more conventional explosives is also limited. The ability  of these technologies to effectively detect explosives on people and their  belongings, as well as the expectations of the public for openness and  speed when using rail, will likely be key drivers in decisions about which  technologies should be applied, and in what capacity. Other important  characteristics of the technologies, including the mobility, durability, and  the size of the equipment, may limit deployment options for explosives  detection technologies in passenger rail. The ability of these technologies  to effectively detect explosives often depends on a human operator and  the development of a strong concept of operations that defines the  processes used to screen passengers and their belongings and the roles  that people and technology play in that process will be critical.
When considering the options for securing passenger rail, it is important  that policymakers also take into account the cost and legal implications of  securing systems that are so open and widely used by the public. The lack  of funding from passenger rail operator budgets means that the purchase  and maintenance of explosives detection technologies would likely  originate from or be highly subsidized by the federal government.  Moreover, the wide scale use and reliance on these systems by the public  means that individuals and advocacy groups may raise concerns about any  technology that screens passengers or their belongings. An effective risk  management process that continuously examines the risks posed by  explosives to the passenger rail environment and considers the various  technical, operational, and policy considerations when determining  alternative solutions to address the explosives risk should result in an  effective identification of the role that explosives detection technologies  can play in securing passenger rail.
section_title: Agency Comments and Our Evaluation
paragraphs: We provided draft copies of this report to the Secretaries of Homeland  Security, Defense, Transportation, Justice, and Energy for review and  comment. DHS’s TSA and the Department of Transportation provided  technical comments which we have incorporated as appropriate. The  National Nuclear Security Administration of the Department of Energy  agreed with our report and also provided technical comments which we  incorporated, as appropriate. The Department of Defense provided  technical comments which we have incorporated as appropriate. The  Department of Justice stated they had no comments on the draft report.
We will send copies of this report to the Secretaries of Homeland Security,  Defense, Transportation, Justice, and Energy, and appropriate  congressional committees. The report will also be available at no charge  on the GAO Web site at http://www.gao.gov.
If you or your staff has any questions about this report, please contact  Nabajyoti Barkakati at (202) 512-4499 or barkakatin@gao.gov or David  Maurer at (202) 512-9627 or maurerd@gao.gov. Contact points for our  Offices of Congressional Relations and Public Affairs may be found on the  last page of this report. GAO staff that made major contributions to this  report are listed in appendix II.
section_title: Appendix I: Scope and Methodology
paragraphs: To determine what explosives detection technologies are available and  their ability to help secure the passenger rail environment, we met with  experts and officials on explosives detection research, development, and  testing, and reviewed test, evaluation, and pilot reports and other  documentation from several components within the Department of  Homeland Security including the Science and Technology Directorate, the  Transportation Security Laboratory; the Transportation Security  Administration (TSA); the Office of Bombing Prevention; and the United  States Secret Service; several Department of Defense (DOD) components  including the Naval Explosive Ordnance Disposal Technology Division  (NAVEODTECHDIV), the Technical Support Working Group (TSWG), and  the Joint Improvised Explosive Device Defeat Organization (JIEDDO);  several Department of Energy (DOE) National Laboratories involved in  explosives detection testing, research and development including Los  Alamos National Laboratory (LANL), Sandia National Laboratories (SNL),  Oak Ridge National Laboratory (ORNL), and Idaho National Laboratory  (INL); and the Department of Justice (DOJ) including the Bureau of  Alcohol, Tobacco, Firearms, and Explosives (ATF), because of its  expertise in explosives detection. We also observed explosives detection  canine testing at the ATF’s National Canine Training and Operations  Center in Front Royal, Virginia. We also observed a TSA pilot test of a  standoff explosives detection system at a rail station within the Port  Authority Trans-Hudson passenger rail system (PATH). In addition, we  made site visits to LANL and SNL to observe the research and  development work being done and to interview experts on explosives  detection technologies. We also interviewed several manufacturers of  explosives detection technologies and attended an industry-wide  exhibition and demonstration of explosives detection equipment products.  In addition, we attended a symposium and workshop on explosives  detection organized by DOD’s Combating Terrorism Technical Support  Office, the 2009 DOD Explosive Detection Equipment Program Review at  NAVEODTECHDIV, and an academic workshop on explosive detection at  DHS’s Center of Excellence for Explosives Detection, Mitigation, and  Response at the University of Rhode Island. We also interviewed  government officials involved with securing passenger rail in the United  Kingdom. Finally, we visited six domestic passenger rail locations that  were involved in testing various types of explosives detection technologies  to either observe the testing or discuss the results of these tests with  operators. Table 3 is a listing of the passenger rail locations we visited.
In determining which explosives detection technologies were available  and able to secure the passenger rail environment, we considered tho technologies available today or deployable within 5 years, technolo which could be used to screen either passengers or their carry-on items,  and technologies which were safe to use when deployed in public are determining the capabilities and limitations of explosives detection  technologies we evaluated their detection and screening throughput  performance, reliability, availability, cost, operational specifications, and possible use in passenger rail. We also restricted our evaluation  to those  technologies which have been demonstrated through tests, evaluations and operational pilots, to detect explosives when tested against  performance parameters as established by government and militar of the technologies.
We also obtained the views of various experts and stakeholders during a panel discussion we convened with the assistance of the National  Research Council on August 11-12, 2009. Panel attendees included 23  experts and officials from academia, the federal government, domestic  and  foreign passenger rail industry organizations, technology manufacturers,  national laboratories, and passenger rail industry stakeholders such as  local law enforcement officials and do operators. During this meeti applicability of explosives detecti environment and the operational and  chnologies in th implementing these te expressed during this panel are not generalizable  represented  summary of the current avai detection and industry views on their applicability to passenger rail.  ng, we discussed the availability and  chnologies for the passengon te policy im e rail environm ent. While the views  ce, they did p across all fields  rovide an overall  To determine wha impact in determining the role of explosives detection technologies in the  passenger rail environment, we reviewed documentation related to the  federal strategy for securing passenger rail, including TSA’s Mass Transit  Modal Annex to the Transportation Systems Sector Specific Plan, and  other documentation including DHS reports summarizing explosives  detection technology tests conducted in passenger rail to better  understand the role and impact that these technologies have in the  passenger rail environment. We reviewed relevant laws and regulations  governing the security of the transportation sector as a whole and  passenger rail specifically, including the Implementing Recommendations  of the 9/11 Commission Act. We also reviewed our prior reports on  passenger rail security and studies and reports conducted by outside  organizations related to passenger rail or the use of technology to secure  passenger rail, such as the National Academies, Congressional Research  Service, and others to better understand the existing security measures  used in passenger rail and operational and policy issues. During our  interviews and expert panel mentioned above, we also discussed and  identified officials’ views related to the key operational and policy issues  of using explosives detection technologies to secure passenger rail. While  these views are not generalizeable to all industries represented by these  officials, they provided a snapshot of the key operational and policy views.  t key operational and policy factors could have an  During our visits to six rail operator l detection testing, we interviewed officials regarding operational and polic issues related to technology and observ selected these locations because they had completed or were currently  conducting testing of the use of explosives detection technology in the rail  environment and to provide the views of a cross-section of heavy rail,  commuter rail, and light rail operators. While these locations and offici tire passenger rail industry, they  views are not generalizeable to the en ed passenger rail operations. We  als’  provided us with a general understanding of the operational and policy  issues associated with using such technologies in the rail environment. In  addition, we utilized information obtained and presented in our June 2009  report on passenger rail security. For that work, we conducted site visits,  or interviewed security and management officials from 30 passenger rail agencies across the United States and met with officials from two reg transit authorities and Amtrak. The passenger rail operators we visited or  interviewed for our June 2009 report represented 75 percent of thenation’s total passenger rail ridership based on the information we  obtained from the Federal Transit Administration’s National Transit Database and the American Public Transportation Association.
section_title: Appendix II: GAO Contacts and Staff Acknowledgments
subsections: section_title: GAO Contacts
section_title: Staff Acknowledgments
paragraphs: In addition to the contacts named above, contributors to this report  include Amy Bowser, William Carrigg, Nirmal Chaudhary, Frederick K.  Childers, Christopher Currie, Andrew Curry, Richard Hung, Lara Ka Leyla Kazaz, Tracey King, Robert Lowthian, and Maria Stattel.