Road Magnets Tested By Volvo For Autonomous Driving

Volvo is counting on magnets embedded in the road to make autonomous driving feasible on a large scale.

Volvo Car Group said it has completed a research project using magnets in the roadway to help the car determine its position. The research, which has been financed in strategic co-operation with the Swedish Transport Administration (Trafikverket), is said to be a potential key to the implementation of self-driving vehicles.

Volvo stated reliable and highly accurate positioning is one of the crucial issues in the development of self-driving cars.

The benefit of road-integrated magnets is they remain unaffected by physical obstacles and poor weather conditions; established positioning technologies such as GPS and cameras have limitations in certain conditions.

“The magnets create an invisible ‘railway’ that literally paves the way for a positioning inaccuracy of less than one decimeter. We have tested the technology at a variety of speeds and the results so far are promising,” said Jonas Ekmark, preventive safety leader at Volvo Car Group.

Volvo Cars currently plays a leading role in an autonomous driving pilot project in which 100 self-driving Volvo cars will use public roads in everyday driving conditions around the Swedish city of Gothenburg.

“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,” added Ekmark. “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.”

The road magnets could have other benefits. In parallel with the potential in the field of autonomous driving, Volvo said road-integrated magnets open up a number of other possibilities:

  • Incorporating magnet-based positioning in preventive safety systems could help prevent run-off road accidents.
  • Magnets could facilitate accuracy of winter road maintenance, which in turn could prevent damage to snow-covered objects, such as barriers and signs, near the road edge.
  • There is also a possibility of more efficient utilization of road space since accurate positioning could allow lanes to be narrower.

To test the magnets, Volvo Cars’ research team created a 100-meter long test track at the company’s testing facilities in Hällered outside Gothenburg, Sweden. A pattern of round ferrite magnets (40×15 mm) was located 200 mm below the road surface and the test car was equipped with several magnetic field sensors.

Volvo explained the research program was designed to evaluate crucial issues, such as detection range, reliability, durability, cost and the impact on road maintenance.

“Our experience so far is that ferrite magnets are an efficient, reliable and relatively cheap solution, both when it comes to the infrastructure and on-board sensor technology. The next step is to conduct tests in real-life traffic,” said Ekmark.