Nothing vexes prison guards like a jailbreak.
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Now, corrections officials around the country are preventing escapes with technology sold by two companies. Their answer is not higher walls and shorter bedsheets.
Ensco Inc. of Springfield, Va., and Geovox Security Inc. of Houston have devised ways of finding would-be escapees at the prison gate by listening for their heartbeats.
Adapting the same techniques that geologists use to detect earthquakes and oil fields, Ensco’s MicroSearch system and Geovox’s Avian system place sensors on a car or truck body to listen for the heartbeats of anyone hiding in the vehicle.
“Unless they’re a lawyer or a salesman, they have to have a heart,” quipped Paul Lockhart, MicroSearch program manager at Ensco.
Prisons, which routinely search vehicles at the “sally port,” or gate, can cut vehicle search times to as little as 15 seconds. A manual search of a loaded tractor-trailer can take two hours or more, officials said.
Stopping an attempt to escape by vehicle is crucial simply because a prisoner on wheels can get farther faster, said Mark White, a former Texas governor who now is president of Geovox.
“When someone climbs the fence, they’re on foot,” White said. “But through the sally port, they’re escaping at 50 miles an hour.”
Both companies say they are making inroads with prisons, military bases and other secure facilities around the country that make vehicle searches a requirement.
Geovox’s Avian was credited with foiling the escape of a convicted murderer who was found in a truckload of basketballs on the way out of a Tennessee penitentiary two years ago.
Six of the 25 state prisons in Pennsylvania began using the Geovox system in a pilot program about a year ago. In New Jersey, the state prison at Trenton installed Ensco’s system in February.
The Pennsylvania facilities in the pilot program include Graterford Prison in Montgomery County–scene of a 1983 jailbreak by two men who climbed into a cabinet that was trucked through the prison gates.
Since the $50,000 machines were installed, “there haven’t been any instances where we’ve found anybody trying to escape,” said Mike Lukens, Pennsylvania corrections spokesman. But the department has been routinely testing the system, and “it’s worked pretty well,” he said. Lukens also said no decision has been made about using the technology in other state prisons.
In one test, a security guard hid among mattresses piled inside a large truck, and the heartbeat monitor detected him, Lukens said.
Both companies’ heartbeat finders use geophones, devices in use for decades by mining companies and seismologists to detect ground movement. Most geophones use magnets and tiny weights to sense minute vibrations.
Lockhart said the fist-size geophones, and software running complex algorithms on a rugged laptop computer, “listen” for vibrations consistent with a steady heartbeat–a frequency of 4 to 8 hertz–while canceling out vibrations caused by other noises and movements in the vehicle or near it.
“All of this stuff is off the shelf,” Lockhart said.
“People are fallible,” Ensco spokeswoman Michele Pennington said. “But we see through walls.”