Trials to be held for 'road trains' on motorways

You are speeding along the motorway at 70mph and the driver of your car is reading a newspaper while keeping half an eye on a television and making a phone call. But fear not: you can just sit back and relax because you're in a "roadtrain".

Within a decade, this could be a common experience for passengers travelling along Britain's motorways, if trials of a hi-tech car-pooling system prove successful. The technology would enable convoys of up to eight cars to "drive themselves" while linked up by electronic shackles to a lead vehicle.

The driver in the vehicle at the front would do all the steering, braking, gear changes and accelerating and his or her decisions would be electronically transmitted to the cars behind. The effect is designed create a train of cars on the road. The system's designers say it would reduce each vehicle's fuel consumption by as much as a fifth thanks to the aerodynamic efficiency of being tucked in just a few feet behind the vehicle in front.

Safe Road Trains for the Environment (Sartre) is a European Union initiative funded by its Framework 7 research plan and it should be ready to be tried out on test tracks in Britain, Spain and Sweden by next year. Tests are expected to last for at least three years but once the co-ordinators are satisfied it is working well, they intend to try out the system on public roads in Spain.

One of the scheme's major advantages is that most of the required technology already exists and the project team is working out how to make it work together while ensuring drivers and passengers are at least as safe as if they were driving the car independently. Erik Coelingh, technical director of active safety functions at Volvo Cars, which is involved in the project, said: "This type of autonomous driving actually doesn't require any hocus-pocus technology, and no investment in infrastructure. Instead, the emphasis is on development and on adapting technology that is already in existence."

The lead vehicle in a roadtrain is expected to be driven by a professional driver, such as a taxi or lorry driver, who is familiar with the route. Cars wanting to join the moving convoy would be able to link up with the rear vehicle while those drivers wanting to leave would signal their intention before taking back control of the wheel. Once they had pulled out, the remaining cars would close up the gap.

Tom Robinson, of the Sussex-based engineering company Ricardo UK, which is also a partner in the Sartre project, said the scheme had the potential to deliver "very significant safety and environmental benefits".

In order to join the roadtrains, vehicles would be required to have the necessary navigation and communication technology already built in to them. The scheme is aimed primarily at car drivers who have to travel long distances but the project team will also investigate the practicalities of allowing lorries to join the trains.