Communications of the ACM
The Road to Progress
The advanced infrastructure implicit in smart roads could redefine driving.
Credit: NMANewsDirect
Over the last few years, semi-autonomous and automated vehicles have evolved from concept to reality. Automakers, as well as tech companies like Google, have continued to push research and development into new territory. Yet despite advances in automobiles, changes in the highways and byways on which they travel have mostly lagged. Painted lanes are static, markings are often difficult to see, and it is generally up to motorists to judge conditions and react accordingly.
"There is a need for roadways to become more technologically advanced," says Christopher Poe, assistant agency director for the Texas A&M Transportation Institute. Among the new concepts taking shape for roads: magnetic and visual lane guidance systems; temperature-sensitive paints that display weather and road conditions; sensors that relay information to next-generation signs and vehicles; improved lighting, and magnetized surfaces that could charge electric vehicles through induction.
Paving the Way
Existing roadways deliver little more than a surface on which to drive. Design and engineering methods—along with materials—have not changed a great deal over the years. While some sensors and network technologies have appeared in roads—induction loops that allow traffic lights to work on variable timing or to monitor traffic, for example—it is clear the road to progress has hit more than a few speedbumps and barriers.
One area of focus revolves around systems that guide both humans and automated vehicles. Netherlands-based design firm Studio Roosegaarde, for example, has developed a smart highway project that aims to rethink and reinvent surfaces and infrastructure. This includes lane markers that absorb light during the day and glow at night or during inclement weather, dynamic paint materials that depict current road conditions with images of rain or snowflakes, and LED road lighting systems that switch on only when vehicles pass by—even providing cues for a current, safe speed limit. The end goal, says principal Daan Roosegaarde, is to introduce "truly interactive and sustainable environments."
At 3M, researchers have developed highly reflective all-weather lane markings that are more visible to both humans and forward-facing vehicle cameras under wet and dry conditions. The company has also introduced magnetic pavement markings and sensors that help automated cars stay in lanes, even during snowy conditions. "There are opportunities to imbed additional information in our materials, and place these in and around roadways, to improve automated vehicle confidence for lane guidance and other systems," says Tammy Meehan Russell, Global Portfolio Manager for Intelligent Transportation at 3M. Another area of research, she notes, revolves around shifting an analog infrastructure into a digital infrastructure, including digital signage that relies barcodes or other symbols to identify construction zones or high-risk areas.
Sensors and more advanced infrastructure would redefine driving, says Zachary Doerzaph, director of the Center for Advanced Automotive Research at the Virginia Tech Transportation Institute. This might include the use of variable speed limits based on conditions, different speed limits in different lanes (a concept already in use on Virginia’s Interstate 77), and the ability to reverse lanes based on rush hour traffic. Although some freeways and highways already have reverse lanes—often used with high-occupancy vehicle lanes (HOVs)—more advanced roadways would provide more than a single lane or two to reverse. "The major obstacle is capital costs," he says.
A Road Well Travelled
Designers, engineers, and researchers are introducing an array of technologies, including smarter pavements that allow water to seep through or provide greater resilience from potholes and cracks—in some cases relying on bio-asphalt constructed from plant materials and recycled items. In fact, several U.S. states have begun to use "permeable" asphalt. There's also the idea of charging road-adjacent lights and signs from solar cells or heat-conducting materials in the road, including inductive systems that would also recharge electric vehicles.
One solar roadway project has already come to Route 66 in Missouri. Specially engineered solar panels essentially create a roadway made from tempered glass (which can be driven and walked on) and can light up like LED signage and create lines/lane markers in the road without the use of paint. The system also emits enough heat to inhibit snow and ice accumulation. In France, meanwhile, solar technology is in 620 miles (about 100 kilometers) of pavement. The government estimates that one kilometer (about 0.6 miles) of solar roadway could deliver electricity for about 5,000 households.
In the future, Poe says, roads may also have RF technologies built into them so they can communicate data to vehicles and motorists, including guiding them through construction zones or variable lanes. Other wireless technologies are being developed to deliver an alert if a vehicle, cyclist, or pedestrian is approaching from around a blind corner. Also, electric vehicles may charge as they pass over magnetic induction coils in the pavement.
Says Poe, "A great deal of research is taking place that's focused on smart roads and connected infrastructure. The end goal is to introduce technology and systems that create greater flexibility, improve safety, and allow more vehicles to use existing infrastructure."
Samuel Greengard is an author and journalist based in West Linn, OR.
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