Police behaving predictably: The other enemy

     At 3 p.m. on a Saturday in June 2007, an SUV loaded with propane canisters was deliberately driven into the glass entrance doors of the main airport terminal at Scotland's Glasgow International Airport and set ablaze. The canisters did not...

     The security game is repeated every day, or even every shift, giving both sides ample chance to learn and adjust. In game theory, interactions between police and adversaries are called "Bayesian Stackelberg" games.

     What that means in the case of LAX is, users input the locations of routine, random vehicle checkpoints, canine search routes, any security breaches or suspicious activity, as well as data on possible terrorist targets and their relative importance. All of these are subject to change from day to day or hour to hour.

     ARMOR then processes the data and plots random decisions based on calculated probabilities of a terrorist attack at those locations, using advanced mathematical algorithms. In the LAX system, this typically takes less than 90 seconds. Airport police then receive a randomized model of where to go, and when. Tambe believes the system provides security with airtight unpredictability. "My research group created the fastest algorithms available today to solve such games," he says. "Without these algorithms, we would find it impractical to solve such games."

     Before the airport began using ARMOR, LAX dispatchers attempted to shuffle schedules and vary checkpoint sites and deployment times. But Tambe says what LAX was doing was not statistically random, it was merely mixing things up.

     LAX police now have systematized, true randomization.

     "It is now extremely difficult for anyone to predict LAX police operations," Tambe says.

     What would happen if terrorists were to get a copy of the software? Couldn't they solve the predictability puzzle to their own advantage? Tambe doubts it.

     "Even if they got the software and all the inputs, it would be like rolling 50 different dice and expecting to correctly roll the same combination on all 50 pairs," he says.

Six-month trial

     ARMOR was first deployed at LAX as a six-month pilot program in August 2007. The first exercise was to use ARMOR to randomize vehicle checkpoints on Century Boulevard, the airport's primary access road. In February 2008, officials judged the checkpoint trial period a success and put ARMOR in the hands of LAX police for routine operational use.

     James Butts Jr., deputy executive director of Los Angeles World Airports (LAWA), the LAX parent organization, says while ARMOR is presently being used in the deployment of officers at vehicle checkpoint locations, it will soon be employed to randomly schedule LAX's 32 explosive detection canine teams.

     Butts says the ARMOR system has made deployment decisions more efficient and focused, but not necessarily easier. He adds the artificial intelligence program allows users to construct tables of assumptions, which are factored into deployment decisions, allowing intelligent randomization of deployments.

     However, the program is only as good as the assumptions built into its logic engine, he adds.

     "The system has application in any area where there is sufficient information on past threats and plots, whether completed or attempted, that can be analyzed to develop patterns of behavior," Butts explains.

     After the pending canine deployment, LAX police anticipate leveraging the program to determine deployment of patrol, bicycle officers and other airport police resources.

     Meanwhile, ARMOR is attracting attention from coast to coast. Other airports, law enforcement agencies and even commercial businesses are showing interest. LAX has received inquiries from a host of federal agencies, and from countries as far away as India. Recently, LAX officials briefed the Transportation Security Administration in anticipation of using the program to randomize federal air marshal deployment on flights.

     Although ARMOR requires customization for each new customer, these changes are not prohibitive.

     "To deploy at a new location, which has completely new types of requirements, potentially requires creating new algorithms," Tambe says.


     ARMOR grew out of an LAX-USC nexus. CREATE's associate director, Erroll Southers, also happens to be LAWA's chief of Homeland Security and Intelligence. Southers is a former FBI special agent assigned to counterterrorism, foreign counter intelligence and SWAT.

  • Enhance your experience.

    Thank you for your regular readership of and visits to Officer.com. To continue viewing content on this site, please take a few moments to fill out the form below and register on this website.

    Registration is required to help ensure your access to featured content, and to maintain control of access to content that may be sensitive in nature to law enforcement.