Technology which enables cars to "platoon" in automatic driving mode in a convoy has been successfully tested by Volvo.
The EU-funded project, known as SARTRE, was being shown off at the Volvo Proving Ground near Gothenburg, Sweden.
A professional driver leads the car convoy in which each vehicle calculates the other cars' distance, speed and direction and adjusts itself as required. This may allow for cheaper car insurance in the future if driving becomes safer.
Each car is detached from the other and can remove itself from the convoy at any time.
Once locked into the platoon drivers do not need to control their vehicle as they embark on even long-haul journeys.
Engineer Erik Coelingh said: "We are very pleased to see that the various systems work so well together already the first time."
Platooning can improve several things: road safety because it minimises human error which causes at least 80% of road accidents, and it saves fuel consumption by up to 20%.
It is also convenient for the driver because it frees up time for other matters than driving. And since the vehicles will travel at highway speed with only a few metres' gap, platooning may also relieve traffic congestion.
© Press Association 2011