Volvo Car Group Tests Road Magnets for Accurate Positioning of Self-Driving Cars

Volvo has just carried out a research project investigating how magnets in the road could help to ensure that self-driving cars stay in the right lane.

Currently, the reliability and accuracy of car positioning is one of the crucial issues in the development of self-driving cars, as established technologies such as GPS and cameras are plagued with limitations in certain conditions, such as in poor weather. However, the magnets effectively create an 'invisible railway' and enables positioning inaccuracy of less than one decimetre.

Financed by the Swedish Transport Administration and working in collaboration with Volvo, Volvo trialled the magnets using a 100 metre long test-track at their testing facilities in Hällered outside Gothenburg.

A series of round ferrite magnets measuring 4cm by 1.5cm in size were fitted 20cm below the road surface, and the car was fitted with several magnetic field sensors. Trialing self-driving cars on this test road at a variety of speed levels, Volvo successfully proved that these magnets can create pinpoint accuracy of positioning. They now intend to move to an on-the-road trial of self-driving cars.

“Our aim is for the car to be able to handle the driving all by itself. Accurate, reliable positioning is a necessary prerequisite for a self-driving car," explains Jonas Ekmark, Preventative Safety Leader at Volvo Car Group. “It is fully possible to implement autonomous vehicles without changes to the present infrastructure. However, this technology adds interesting possibilities, such as complementing road markings with magnets."

These road-integrated magnets open up many other possibilities. They could be incorporated into preventative safety systems to help prevent run-off road accidents, improving the accuracy of winter road maintenance, and the possibility of more efficient utilisation of road space allowing road lanes to be narrower.