Volvo Car Group has completed a research project using magnets in the roadway to help an automated car determine its position, the automaker has announced.

Road-integrated magnets remain unaffected by physical obstacles or poor weather conditions unlike GPS or cameras and remain the most reliable and accurate in the positioning of self-driving cars, according to Volvo.

"The magnets create an invisible railway that literally paves the way for a positioning inaccuracy of less than one decimetre. We have tested the technology at a variety of speeds and the results so far are promising," said Jonas Ekmark, Volvo's preventive safety leader.

During the test, Volvo created a 100-meter (328-foot) track at the company's testing facility in Sweden. The company used ferrite magnets located 200 mm (7.87 inches) below the road's surface.