A petroleum-laden truck has been stopped in its tracks by remote-control signals sent via satellite. The technology is one of a small number of devices being developed to prevent terrorists being able to hijack trucks and use them as weapons.

Engineers at Satellite Security Systems’ headquarters in San Diego, California, took less than 40 seconds to bring a truck in Sacramento, 850 kilometres away, to a standstill. They used Motorola’s satellite data transfer network with its network of base stations to beam instructions to a small transceiver in the truck.

Since 9/11, the US government has worried about terrorists using trucks transporting flammable or hazardous loads to attack buildings or bridges. The State of California has already drafted legislation that would make “stopping devices” a compulsory addition to all hazardous vehicles by 2005.

“A fuel truck could be used for a terrorist bombing since it contains an explosive potential roughly equivalent to that of a commercial jetliner,” says Bill Wattenburg, an engineer at Lawrence Livermore National Laboratory in California.

The Satellite Security Systems (S3) technology involves burying a 13cm-long, square transceiver under the dashboard of the vehicle. This processes the instructions sent by satellite and switches off the engine. “It’s a very gradual, sublime stop,” says Marvin Serhan, vice president of business development at S3.

The S3 demonstration took place at a California Highway Patrol facility three weeks ago but was not announced until recently. Since the test, a 50-strong fleet of trucks that transports petroleum in California and neighbouring Nevada has been fitted with the technology.

S3 has previously used a similar technology to halt the “bait” cars used by some law enforcement authorities to catch automobile thieves.

Wattenburg argues that hijackers could jam the S3 system with a device that emits waves of the same frequency. “They’ll find out the frequency just as quickly as kids figure out how to hack into computers,” says Wattenburg. But Serhan says it is not trivial to jam the S3 system, as the devices can work on a range of different frequencies. “How would a terrorist know which one we were using?” he asks.

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