It’s a magnetic idea. The Swedish automobile manufacturer Volvo, known the world over as an innovator of automobile technologies, has applied its innovative prowess to developing several unique self-driving car technologies – the latest one using magnets.

Where most self-driving vehicles in development across the industry use onboard radar that receive signals bouncing off objects all around, Volvo’s latest autonomous driving system takes readings from magnetic sensors embedded in the roadway itself.

Will Volvo’s magnet-driven cars attract or repel government sponsorship? As with any technology, it is not enough simply to design a system that works.

It must also be cost feasible.

Volvo’s Self-Driving Cars

Volvo’s driving passion for autonomous vehicles goes back a few years. Its first concept – the SARTRE Road Train, successfully tested in 2011 – was a car designed to follow a lead vehicle driven by a human driver. The trailing driverless vehicle simply mimicked the lead vehicle’s operation, copying its turns and speed. A series of driverless vehicles could be lined up like an endless train behind the lead vehicle with barely a few feet distance bumper to bumper, perfect for keeping busy freeways moving along.

In 2013, Volvo unveiled a second autonomous system for city driving, using onboard radar that emits a 360 degree signal and reads the echoes bouncing back. The still-active Drive Me Program aims to put 100 such self-driving vehicles onto the streets of Sweden’s capital city of Stockholm by 2017 in an attempt to beat rivals Nissan and Google – both of whom are aggressively developing autonomous vehicles of their own.

But Volvo wants to keep all its options open. For its third concept, the company is experimenting with a sensor system that reads magnetic fields generated by magnets implanted in the roadway.

Early testing used neodymium magnets 0.78 inches in diameter by 0.39 inches thick, and ferrite magnets 1.18 inches in diameter by 0.2 inches thick encased in plastic tubes buried vertically into the roadway close to the surface, spaced about 1 yard apart. Onboard computers could calculate the car’s position to within 4 inches when traveling below 45 mph.

Later tests using magnets glued to the surface of the roadway produced even better results while managing to control the vehicle at speeds exceeding 90 mph. Not only is this system more reliable at higher speeds, it is also much less costly to install and maintain.

Its Un-magnetic Price Tag

Unfortunately, even that cheaper on-surface configuration is likely to be too pricey. By the company’s estimates, upgrading an already existing highway with the quantity of magnets required would cost some $39,275 per mile of roadway just two lanes wide.

To put that in perspective, the International City/County Management Association (ICMA) Center for Performance Measurement informs that road rehabilitation expenditures per paved lane mile average $3,867, or $7,734 for two lanes – just for typical roadway maintenance of basic pothole filling and crack sealing.

Volvo is driving up the wrong street if it believes America is going to buy into its magnet system.

The currently deplorable condition of America’s highway infrastructure has long been publicized, with the underfunding of roadway maintenance long criticized. If the government can’t even allocate a mere $7 to $8 thousand per mile to fixing its crumbling highways, it will definitely not be spending 5 times that amount installing magnets.

Even if the system were installed in only the most congested stretches of highway, any scraping of the road surface by debris from falling objects or a previous vehicle crash could damage or remove long sections of sensors, leaving gaps in important data collection along dozens of yards or roadway. Moreover, motorists are highly unlikely to purchase an entirely new onboard navigation system which would only be used on certain sections of roads and highways.