The first time you drive a car with lane-keeping assist, it might seem as if we’re on the verge of self-driving cars.
The steering wheel turns itself and keeps you in between the lines. Even though most systems require you to keep your hands on the wheel, it’s tempting to sit back and let it take over.
But it only works if your car can “see” the lines. If the lines are faded, or you hit a little water on the road, the car could suddenly stop steering itself and leave you unexpectedly on your own.
“Autonomous vehicles and modern safety systems are able to read current road guidance indicators in fair weather,” Jonathan Cliffen, an application development engineer for 3M Canada, said in an e-mail. “Nighttime driving and driving in the rain limit the ability for these advanced systems to perceive their environment.”
Lane-keeping assist systems use a camera to gauge the contrast between lines and the pavement. And when that contrast isn’t clear, the systems don’t work as well.
Winter weather and snowplows can wear away painted lines over just one season, making them difficult to see by cars or drivers.
Automakers are working on technology that could make cars more adept at figuring out where they are and what’s around them. These include connected car technology that lets cars talk to other cars or infrastructure, and GPS-based driver assistance systems that know where the lanes are supposed to be on the road.
But part of the solution might just be making roads that are easier for cars to read. And that doesn’t have to involve futuristic tech.
The company that operates Highway 407, a toll road that runs through the Greater Toronto Area, is testing a reflective pavement marking that is designed to be easier for driver-assistance systems to see.
“A major portion of our road is concrete and it’s grey – we found that regular white [painted lines] didn’t show up well during the day,” says Craig White, vice-president of highway and tolling operations with 407ETR Concession Co. Ltd. “We were discussing this with 3M and they said, ‘We have a product that’s not available yet commercially.’”
The tape, which is installed in recessed lines in the road along 2.5 kilometres of the toll highway west of Toronto, doesn’t use sensors or talk to cars. It’s embedded with reflective ceramic beads that make it up to six times brighter than the reflective paint that’s normally used.
The goal was to make lines that were easier for drivers to see, too, especially at night and in the rain.
The tape was installed last fall and made it through the winter without damage from snowplows, White says, but there hasn’t been much feedback from road users so far.
“I don’t think everybody knew where it was or what it was,” White says.
And, even though White and 3M declined to specify the exact cost, it’s a lot more expensive than painted lines.
“Painted lines are very inexpensive – a fraction of a dollar a metre. This stuff costs multiples of $10 per metre,” White says. “That’s one of the reasons you won’t see this widespread very quickly.”
Paving the future?
Even cheap run-of-the-mill road paint might be easier to see if it’s recessed in a shallow groove on the road. With that in mind, Ontario’s Ministry of Transportation is undertaking a trial study related to the use of recessed markings.
“In addition to providing enhanced contrast and superior durability, this initiative could facilitate better outcomes for machine-reading, autonomous and connected vehicle technology,” the department said in an e-mailed statement.
But right now, cameras in cars still can’t see under snow, no matter how big or bright the lines are.
“No camera I know of will be able to see those markings through snow,” White says. “So there are still problems that have to be solved.”
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