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Last Updated: Wednesday, 14 July, 2004, 10:41 GMT 11:41 UK
Police, camera, zapper
A futuristic gadget which disables suspect vehicles with radio waves could soon be used by police in car chases. It's their latest weapon in safely ending pursuits.

The invention of a device which is effectively a stun gun for cars has roused the interest of senior officers.

They believe it could offer a safe alternative to high speed chases, which all too often result in deaths.

The number of people killed by crashes involving police cars in the UK is "far too high", the Police Complaints Authority warned last year.

With cop-show style chases off-limits, the potential for inventive ways to halt a runaway car has never been greater.


At the flick of a switch, the zapper directs a beam of intensely concentrated radio waves at the target car and makes it stall, safely bringing it to a halt.

The system works, according to its inventor Dr David Giri, because it turns the very technology which has revolutionised motoring over the past decade against the driver.

Computer chips are now used in most cars to control the fuel injection and engine firing systems. By knocking these out the car cannot be driven.

The system relies on a battery and a series of capacitors stored in the police car's boot. The radio waves are produced by sending a short burst of electricity into a roof-mounted antenna, which has a target range of about 50m.

Tests on the device are being conducted by Home Office scientists and police also appear to be keen on it.

"It seems to have potential, there's no doubt about it," said Mick Barker of the Police Federation.

But officers still want to know more about the effect of the device on non-suspect cars in the area. And, of course, it does not work on vehicles built before on-board computers were standard.


A super-strong spiked net which wraps itself around a car's wheels and punctures its tyres is another device attracting a good deal of attention.

The X-Net
The X-Net is already being used by the military

Developed by UK defence research firm Qinetiq, the X-Net is made from Dyneema, a fibre which is said to be eight times stronger than steel and is also used to make bullet-proof jackets.

The 8m by 2.5m X-Net is portable and can be laid across a road in the path of an oncoming vehicle to bring it to a complete standstill, typically within 75m.

Because the net becomes entangled around the wheel axle it is impossible to continue driving.

The X-Net has already been used by US Marines in Haiti and could also become part of troops' equipment in Iraq, where Qinetiq believes it could halt vehicles being used by terrorists.

Back in the UK the firm hopes it could be used to stop joy-riders, as the net causes minimal damage and, despite its strength, can be cut away with a knife.

Similar devices are being developed in the US, where there is particular interest in their potential to stop cars at border crossings.


The onward march of the mobile phone continues, with the ubiquitous device finding a potential new use as a weapon in the fight against vehicle crime.

Systems allowing a car to be immobilised and tracked are being developed primarily for the owners' benefit, but the technology could also help police.

One such idea allows a stolen car to be safely stopped by cutting off its fuel supply via mobile phone. It can also limit the number of engine revolutions, thereby restricting the vehicle's speed.

Steering is not affected and police can be directed to wherever the car was left via satellite tracking systems, says Cheshire firm Mobilizer Ltd, which is working on the idea with the help of a 20,000 government grant.


The reality of the gadgets currently available to officers is far more humdrum than the hi-tech options they could soon have.

Most forces rely on stingers, a portable bed of nails which will be familiar to viewers of shows like Police, Camera, Action, where rogue drivers are often shown being thwarted by the devices

Road block
UK police consider road blocks a last resort

The 15ft-long stingers are thrown across a road, into the path of a vehicle, with spikes puncturing its tyres.

Because the stainless steel spikes are hollow and break off in the tyres, they are deflated fairly slowly - in 20 to 30 seconds - without the risk of a dangerous blow-out.

Many forces are particularly keen on stingers as they are reluctant to get involved in a potentially dangerous high-speed chase for what might be a minor crime.


When left without the chance to use a stinger, let alone a radio waves zapper, X-Net or mobile phone immobiliser, police have few options open to them.

Hollywood movies may show officers ramming a car, or positioning their vehicles to make a roadblock, but in the UK such tactics are considered dangerous and a last resort.

"In this country one has to weigh up what may be a simple motoring offence against the possible death of driver or another person who has nothing to do with the incident."

One popular technique is Tpac, where police position themselves around a suspect car and force it to slow down by reducing their own speed.

Apart from that, there's always following along at a safe distance, or in a helicopter, and waiting for the driver to stop and make a break for it on foot, or run out of petrol.


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