Pothole prevention: smart roads signal repair needs

 

By Brooke Kansier

If Michigan ever gears up to fix its crumbling roads, engineers might be well-served to consider a new ingredient in the road-making mix.

It’s a sensor developed by Michigan State University, and it could have a big impact on road budgets and repairs nationwide.

The sensor records traffic data and measures impacts and damage to roads. It communicates that information to engineers who could use the data to fix roads before they become seriously damaged — making maintenance significantly easier and cheaper.

“If you’re trying to detect something in the roads, you have to do it at the bottom of the road, you cannot do it only at the surface, because once the damage has reached the surface it’s kind of too late,” said Nizar Lajnef, the Michigan State University assistant professor of civil and environmental engineering who oversees the project. “You need to detect the problem early, before it turns up on the surface.”

The sensors “wake up” whenever a vehicle drives over them and record road stress and damage. When engineers check the sensors wirelessly, they can better understand which parts of the road may need internal repairs, wear faster and need more attention.

And the sensors are entirely sustainable — powering themselves from the vibrations of the same traffic they record. It’s not enough to power traffic lights or other devices, but it is enough to keep the sensors operating.

The pressure and vibrations created by vehicles serves a dual purpose — generating power and providing valuable data for proactive repairs.

That’s important because they can’t be removed for battery changes.

“You just mix it with the concrete, mix it with the asphalt, and then you just lay it down on the road and it starts working,” Lajnef said.

The sensors don’t require maintenance and should power themselves for the life of the road.

“The sensor needs less than a microwatt of power,” said Shantanu Chakrabartty, a professor of computer science and engineering at Washington University, who formerly worked with MSU and in developing the technology.. “To give an idea, one microwatt is about ten times less than the energy it takes to power your wristwatch.”

Chakrabartty said the technology has implications for things like body implants, such as in cases of knee replacements. It can monitor implants after surgery and track bone growth after a break. It could measure and improve the efficiency of windmills, he said.

The project began in 2006, and moved to commercial development in 2010, Chakrabartty said. The U.S. Department of Transportation and the Federal Highway Administration have supported the project with grants totaling $2 million, he said.

The sensors are now being tested at the Turner Fairbanks Research Lab in Washington D.C. where researchers have access to different vehicle weights and road types and can better control the testing.

They could be tested in small sections of actual roads in Virginia and Michigan within the next year, Chakrabartty said. A commercial release is still a few years away.

“Within a couple of years, we will have a better idea of the reliability and also the performance of the sensors under real conditions,” he said. “Right now, we have tested everything within testing facilities, where we simulate the road and we simulate damage. But, in a couple of years, we will have better results.”

The developers hope that the sensor will become a basic part of highways.

“Our goal right now is to reduce the cost to about a dollar per sensor,” Chakrabartty said. “And then, based on that, we have to plan what other features we would need on top of that.”

Those features would mainly be tweaks to make it easier to use.

How many are needed per mile of road depends on the road. However, the number will likely be in the hundreds for the average mile stretch.

In the long run it will still be a cheaper and more effective solution than constant road repairs. The sensors will only need to be replaced when roads are replaced, which can be more than a decade.

User-friendliness and a solid interface are also important aspects the researchers are testing.

“There’s a lot of customer education that needs to go into it,” Chakrabartty said. That includes learning what highway departments want the data displayed.

If the researchers can demonstrate to transportation departments that the technology is effective, improves repairs and reduces costs, Chakrabartty is confident that they’ll use the technology.

“The fact that they generate their own power, we think, is a good selling point,” Lajnef said.

Chakrabartty agrees.

“Sustainability and environmental impact is one of the key aspects of this technology,” he said. “Effectively, it decreases the carbon footprint from that point of view, because you don’t take on the maintenance blindly, only when it’s needed.”