Carmakers have been stuffing intelligence and instrumentation into cars since at least 1980 in an effort to get them to drive themselves, safely.
Autonomous-car designs almost all depend on stuffing enough intelligence into a car to allow it to drive. Volvo is experimenting ways to make the road do some of the work as well.
The Swedish carmaker launched an EU-funded SARTRE Project, whose goal is to get cars to gather into cooperative "road trains" travelling at a consistent speed in a single lane to save gas and reduce lane-change-induced chaos.
It has assembled a long list of self-sensing and driver-assist technologies for its trucks and cars. It is ambitious enough about its vehicular autonomy that it is about to launch a three-year road test of 100 self-driving and driver-heavily-assisting cars that it will turn loose on the streets in and around the city of Gothenburg, Sweden.
Volvo is using magnets to help autonomous cars maneuver through the streets.
The Volvo Car Group just finished a research project designed to make roads do their bit to help drivers stay in-lane as well – by implanting magnets that can mark lane divisions for cars equipped with sensors able to detect them at highway speeds and identify any flat strip with a magnetic field on the left and one on the right as the place it wants to be.
GPS- and camera-based systems have far more potential for general-purpose location-awareness, navigational, parking and collision-avoidance systems, but are severely limited in poor visibility and at very close distances, according to Volvo's announcement March 11.
Magnets are especially good at identifying lane divisions under snow and ice that could confuse vision and radar system. Magnets are also better than reflectors or other surface-mounted vison-assisting road decorations because they can be mounted flush or even underneath a thin layer of asphalt, and let road designers be far more precise in defining lane boundaries.
"The magnets create an invisible ‘railway’ that literally paves the way for a positioning inaccuracy of less than one decimeter," according to Jonas Ekmark, Preventive Safety Leader at Volvo Car Group, who was quoted in the announcement.
To test the magnets, researchers embedded round, 40mmx10mm ferrite magnets 200 mm below the surface of the road and equipped test cars with magnetic sensors.
"We have tested the technology at a variety of speeds and the results so far are promising," Ekmark said. "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."
Volvo plans to install the road magnets in roads around Gothenburg, to test in combination with the other autonomous-driving systems packed into the 100 pioneering Volvo XC90s that will self-decisively be prowling those roads between 2014 and 2017.
Magnets aren't strictly necessary to make any of the autonomous-driving technology work correctly, Ekmark said, but could make lane identification and control easier under some circumstances.
The test results are interesting, as is the potential of magnets to make self-driving cars safer, according to Claes Tingvall, traffic safety director at the Swedish Transport Administration. "A large-scale implementation of road magnets could very well be part of Sweden's aim to pioneer technology that contributes to sustain mobility," he said in the release.
"Our aim is for the car to be able to handle the driving all by itself," Ekmark said. "It is fully possible to implement autonomous vehicles without changes to the present infrastructure. However, this technology adds interesting possibilities."