For Daan Roosegaarde, it was the frustration of being stuck in traffic on a major dual carriageway in the Netherlands that first sparked his curiosity about the role roads could play in harnessing energy.
"I was sitting in my car and it hit me," he says of the moment four years ago. "Why do we talk about energy-efficient cars and invest billions into their research and development? Yet roads themselves are rarely ever considered."
The Dutch artist was already known for imaginative projects fusing technology and energy. In 2008, he created a dance floor harnessing energy generated from the impact of dancing clubbers to produce electricity. As he sat in a traffic jam, he wondered whether roads could play a similar role.
The result was his Glowing Lines project: three light-emitting lines painted along a highway in Oss, southern Netherlands. The 500-metre long lines absorbed light by day and glowed at night for up to eight hours - guiding drivers who may otherwise have relied upon overhead lighting.
"Energy is everywhere," says Roosegaarde. "We just need to know how to harvest it."
Roosegaarde is not alone in his observation. Several projects around the world are now exploring whether roads can play a greater role in the production of energy.
The road ahead
US start-up Solar Roadways, for example, is examining if standard asphalt or concrete surfaces can be paved with panels fitted with photovoltaic cells that generate and store electricity.
It has already secured federal government funding and has worked with the Missouri Department of Transportation to install a section of solar panels along a slip road on America's Route 66, which runs from Chicago to Los Angeles.
The trial will explore whether such cells can generate enough electricity to provide power to a nearby building.
In France, road company Colas, in partnership with the National Solar Energy Institute, has installed 2,800 square metres of solar panels along a one kilometre stretch of road in the village of Tourouvre in Normandy.
The company says that these solar panels can generate enough to power the public lighting of a small town.
Siemens, the engineering company, has unveiled its first projects on German motorways with overhead electric cables that allow hybrid diesel electric freight trucks to switch to electric mode when they detect the cables.