HomeNews & PublicationsFeatured StoriesEnhancing the Security of the Nation's Transportation Systems 

August 4, 2010

Enhancing the Security of the Nation's Transportation Systems: Advanced Technology, Systems Engineering, and Testing and Evaluation

Mass transit systems worldwide are a target for terrorist attack because of their high concentration of people and the potential to cause large-scale disruption and fear. Fatal attacks on surface transportation are among the deadliest, ranking just behind attacks on aviation and nearly equaling those on religious and tourist targets.

But unlike post-9/11 aviation systems, mass transit is inherently difficult to secure because of passenger volume, multiple access points with limited inspection and control areas, the need for patron convenience, and the lack of advance purchase and requirement for passenger identification. The 2005 bombings in London are a reminder of the vulnerability of mass transit systems worldwide.

The Department of Homeland Security (DHS) is working to stay one step ahead of terrorist attacks on U.S. transportation systems, and APL is playing a critical role in that effort. Relying on decades of expertise in operational analysis, sensor and materials development, field testing, and systems engineering, the Laboratory provides subject-matter experts to work with DHS to identify and field detection technologies that alert authorities to concealed chemical, biological, radiological, nuclear, and explosive threats.

APL is working to understand the current threat and to anticipate future threats, including smaller quantities of threat material disguised as benign objects. The Laboratory is collaborating with DHS to gather operational scenarios, processes, threats, and threat vectors to establish systems requirements for the next generation of technology.

APL’s team includes physicists who understand the detection phenomenology of the systems, chemists who understand the composition of the threats and how their signatures can be exploited, engineers who understand the operations and how to best employ detection systems, and systems engineers who understand the interdisciplinary relationships and can coherently integrate the parts to identify and support the nation’s future needs. These experts expedite the test and deployment cycle by proactively acquiring potential technology solutions and by reliably characterizing their capabilities to enable optimum employment.

APL is pivotal to DHS’s efforts to evaluate technologies for detecting person-borne improvised explosive devices (PBIEDs) and vehicle-borne improvised explosive devices (VBIEDs). PBIEDs pose a unique challenge because of the many ways a terrorist can disguise these devices. The Laboratory also evaluates cutting-edge technologies capable of screening passengers in both checkpoint and wide-area applications. Several of these devices use millimeter and terahertz waves to detect concealed items under several layers of clothing. One passive millimeter wave system assessed by APL has undergone pilot demonstrations throughout the country in high-profile event venues.

VBIEDs present challenges different from those of vehicles laden with large quantities of explosives to administer spectacular and devastating damage to targets. Recognizing the VBIED threat to transportation facilities, APL is identifying and evaluating new detection technologies to counter it. One of the latest technological advancements in VBIED detection is the use of low-dose X-rays in screening portals to image a vehicle as it drives through a security checkpoint. APL scientists and engineers have tested several vehicle-screening detection technologies to assess threats concealed in passenger cars, trucks, buses, and railcars. Recently, a novel detection concept that synthesizes under-vehicle pictures with X-ray backscatter images was successfully demonstrated for the first time in the United States. The combination of these two technologies enabled DHS to screen the underside and inside of subway cars as they exited the rail yard, with minimal operational impact and delays. APL was integral in the systems engineering, testing and evaluation, and implementation of these systems in the pilot demonstration.

Leveraging core competencies for the benefit of multiple sponsors is an APL hallmark. Knowledge acquired and skills developed on previous efforts are being applied to evaluate nonintrusive inspection technologies for border crossing. The intent is to use X-ray portal capabilities to detect contraband (e.g., currency, drugs, and weapons) and personnel concealed in vehicles. The characteristics of these items create different challenges because of their variation in signatures, desired detection threat quantities, and concealment opportunities. By drawing on the expertise gained through extensive technology testing and coupling it with a detailed understanding of operational needs, APL is providing recommendations for technologies and concepts of operation that will lead to enhanced system performance in the field, thereby increasing the security of the nation’s transportation systems.

RoboCart: Rapid Prototype Robot Delivery Vehicle

Robots have proven useful to first responders, providing situational awareness and helping SWAT teams, bomb squads, HAZMAT units, and other first responders successfully tackle dangerous scenarios. But when the Transportation Security Administration (TSA) tested such a system in the Port Authority Trans-Hudson (PATH) subway tunnel, obstacles posed by track switches, cables, and electrical boxes in the rail bed and by remote communications in a tunnel environment all but stopped the robot in its tracks. TSA needed an unmanned vehicle that could ride the rails and quickly deliver the robot to the incident site.

In 4 months, APL developed basic system requirements, designed solid models, purchased equipment, and integrated parts into a functional prototype. To produce a low-cost prototype in an abbreviated time frame, the team selected radios, antennas, motors, motor controllers, and batteries that are all commercially available, off-the-shelf items. Electric bicycle/scooter motors were adapted to flanged wheel assemblies, providing independent four-wheel drive and braking.

The vehicle is designed to be two-person portable with all components fitting into two wheeled cases. The RoboCart, which can be assembled in less than 15 minutes without tools, can deliver a 500-pound payload at about 11 miles per hour with an estimated endurance of more than 5 hours.

RoboCart has undergone extensive testing to assess its functional and operational performance at the B&O Railroad Museum in Baltimore, MD, the National Trolley Museum in Silver Spring, MD, Baltimore’s Fort McHenry tunnel, the Walkersville (Maryland) Southern Railroad, and the PATH subway tunnel. During the PATH testing, RoboCart, travelling unimpeded by obstructions in the rail bed, successfully rescued a robot that had become immobilized half a mile into the tunnel. RoboCart completed the round trip in roughly 6 minutes—a trip that took the robot over an hour, one way.

In the absence of a robot payload, the system has been upgraded to provide stand-alone sensing capabilities for first responders. RoboCart provides two pan-tilt-zoom cameras for remote navigation and surveillance, a chemical detector for environmental sensing, and an audio system for message broadcasting. Additional testing of the upgraded system at PATH is planned for spring 2010.

Simulant Development

When explosive detection systems are undergoing development and certification testing, real explosives are used to prove their viability. But once a system is operational, explosive “simulants” are used for routine testing and training. These simulants replicate particular physical characteristics such as color, texture, molecular weight, and dielectric constant to ensure that the detection systems under evaluation respond to the simulants in the same manner they would respond to the actual explosives.

In 2008, APL scientists and engineers developed cutting-edge explosive simulants to test passive millimeter wave and active terahertz imaging systems for standoff detection of explosives. They validated the simulants based on a verification, validation, and accreditation model developed at the Laboratory in 2007. In side-by-side testing at the U.S. Army Aberdeen Test Center, APL scientists and engineers proved that the millimeter wave and terahertz simulants developed accurately represented their explosive counterparts and could be used in operational settings as test targets.

DHS uses covert testing that simulates techniques that terrorists may use. This testing identifies vulnerabilities in and measures the performance of airport security systems. During these tests, undercover inspectors attempt to pass threat objects through passenger and baggage screening systems. Laboratory scientists and engineers designed novel explosive simulants for whole-body imagers and provided these test kits to the inspection teams. APL staff accompanied these TSA “Red Teams” on covert testing runs throughout the country in summer 2009, providing simulant subject-matter expertise.