It sounds like science fiction - and scary science fiction at that - but, in truth, the technology is here already. And it works.
Last week British technology company Ricardo and Volvo put a road train consisting of two trucks and three cars on a public road for the first time, near Barcelona in Spain, for a journey of 200km among normal vehicles - but only the lead truck had a driver!
The vehicle-platoon test formed part of the Sartre (safe road trains for the environment) project.
A road train consists of a lead vehicle driven by a professional driver followed by a number of self-driving vehicles. The autonomous vehicles use Volvo's existing safety systems, such as cameras, radar and laser sensors, to monitor the lead vehicle, as well as other vehicles in their immediate vicinity.
FOLLOW MY LEADER
Using wireless communication, the vehicles in the platoon 'mimic' the lead vehicle using Ricardo autonomous control - accelerating, braking and turning in exactly the same way as the leader.
The drivers of the vehicles in the platoon can then spend their time working on their laptops, reading or even sit back and enjoy a relaxed lunch.
The project also aims to improve traffic safety, reduce environmental impact and - thanks to smooth speed control - reduce the risk of traffic tailbacks.
Linda Wahlström, project officer for Sartre at Volvo, said: “We covered 200 kilometres in one day and the test turned out perfectly.
“Driving among other road-users is a great milestone in our project.”
During the drive the five vehicles held formation at 85km/h, just six metres apart.
Wahlström explained: “In our trials on the test circuit we tried out gaps from five to fifteen metres, and settled on six metres as being the most practical.”
Sitting in a car travelling just six metres behind another car at 85km/h and relying totally on the technology might sound a bit scary, she added, but experience indicated that people acclimatised very quickly.
The Sartre project has been under way since 2009 and the driverless vehicles have covered about 10 000km - all on test circuits up to now.
But after the successful test on the public roads in Spain, the project wil now enter a new phase with the focus on analysis of fuel consumption.
Wahlström said: “We've learnt a whole lot during this period. People think that autonomous driving is science fiction, but the fact is that the technology is already here.
“We've focused really hard on changing as little as possible in existing systems,” she added. “Everything should function without any infrastructure changes to the roads or expensive additional components in the cars.
“Apart from the software we've developed as part of the project, it’s really only the wireless network installed between the cars that makes them different from the cars available in showrooms today.”