So if GPS is as capable as we are lead to believe, then surely it can be used to provide crash avoidance capability to every person's car in the street. This would of course lead to the demise of the car insurance business and to the reduction in the supply of safety devices for cars that are rarely used, such as air bags.

GPS systems and the satellite network that supports it are making advances in leaps and bounds, reducing the margin of error on the ground to less than 1 metre. This is certainly sufficient to enable developers to construct virtual concept images of standard transport vehicles e.g. trucks, buses, cars, etc. and use them to compile a crash avoidance algorithm for a supervisory controlling system.

Car hire companies and other interested parties categorise and subdivide the size of vehicles into executive, luxury, family saloon, mid range, small, compact, etc. It would be possible to construct a GPS system view of your vehicle from a standard description. The image would reflect the approximate size and shape of your vehicle, erring on the side of larger rather than smaller.

All vehicles would have a GPS image, linked to an idenifier e,g, number plates. It would broadcast to or provide acknowledgment from, a supervisory road traffic control system that is devised along the lines of the air and rail traffic control systems, currently in use.

The need for car insurance would be reduced greatly, if not removed completely and the GPS controlling system would be funded by an increase in, so called Road Tax or Transportation tax. The vehicles are mapped and logged continuously as well as being stopped from colliding with each other. This would mean non-avoidance of the road tax, rapid recovery of stolen and other offending vehicles. Illegal manoevres and parking would also be prevented by close mapping of the road rules to traffic flows.

The next consideration would be how to safely bring a stolen or offender's car to a halt without endangering the offender, the general public and the empowered authorities. Unfortunately, it is commonplace to see car chases between police and perpetrators. These are very dangerous for all concerned. They excite and feed the competitive instincts on both sides. This can reach an hysterical peak that greatly reduces the sense of responsibility and self preservation, thus increasing the aggressive, risk-taking behaviour. It all too often ends in disaster and damage for all concerned.

We come from a hunter gatherers' background and the hunter's chase instinct is still with us. It is exhilarating. The thrill of the chase, the screeching of tyres, the adrenaline rush, the need to be the hero or the villain, is strengthened at these times. The beast is out of the bag and it is too late for rational behaviour and calm negotiations to re-capture it. It will end in tears.

It is far better to disable a perpetrator's vehicle electronically and bring it to a controlled and safe stop, before the adrenaline starts pumping. The use of helicopters recently has lead to an increase in the detection and resolution of car based incidents. The helicopters would tap into the GPS supervisory controlling system and electronically tag a suspect's vehicle. Ground support could then track this vehicle safely from a distance and intercept it at an appropriate time and place. The car would be imobilised electronically, thus minimising the risk to all concerned.

Additional benefits would also be realised. Firstly, without the need for dangerous car chases, the authorities would not need expensive supercars in their fleet and would fall back on more reliable, more economical and less needy models. Thus greatly reducing the fuel costs, the specific training and maintenance overheads involved. It may also reduce the number of macho men that join the authorities simply to race cars legitimately.

Food for thought from the larder.