COMPUTER-controlled cars straight from science fiction are a step closer thanks to a system being developed in Manchester.

A team of scientists believe they have overcome a major safety hurdle - preventing remotely-driven vehicles from crashing as they travel inches apart at high speed.

Centrally-controlled networks have long been the stuff of science fiction, but researchers promise they will eventually cut journey times, improve road safety and allow thousands of extra vehicles on the roads.

Fears of disastrous system failures have held up progress.

But now engineering experts at Manchester University believe extendible bumpers which reach out and `touch' the car in front are the key.

They predict these would allow a constant distance between vehicles in the event of a computer breakdown.

Because of the distance ordinary cars need to keep between them, it is estimated that only five per cent of motorway space is ever occupied by vehicles.

Camera technology

Researcher Dr Aurelio Gonzalez-Villasenor explained: "At present, there is no camera technology sophisticated enough to help a car understand what is going on, so we believe the best method is a physical probe that would touch the car in front and let your car know what speed it should be travelling at."

"A vast amount of further research is needed, but we hope that by tackling the issue of safety and presenting our ideas, intelligent transport systems may arrive just a little bit quicker."

The bumper, or `damper', would touch the car in front and allow the vehicle to regulate its speed in case of a system fault.

Computer simulations have shown groups of up to 20 cars could be `buffered' together.

But the researcher added: "It would require a huge leap in people's trust to allow cars to drive themselves on a motorway at 70mph - not many people would like it.

"And there would also be a huge number of legal issues involved."