From the bridle path to paved and surfaced, to highways offering services in addition, over the centuries our roads have been on the move. And today we have arrived at the so-called 5th generation

 At Ifsttar, the 5th Generation Road (R5G) flagship project (which has close ties with the European Forever Open Road programme) is developing a new type of infrastructure that sets out to be automated, safe, sustainable, and suited to travel needs today, and tomorrow. The objective of R5G is to multiply the functions of ‘captive surfaces, explains Hélène Jacquot-Guimbal, managing director, Ifsttar.

During C0P21, the institute showcased the technical feasibility one of its elements – the positive energy road – which its researchers have been working on for the past five to six years.

Ifsttar developed some of the first formulations of transparent materials made of recycled glass, which gave an inkling of the innovation that now commonly referred to as the ‘solar road/highway’.


In 2015, French construction group Colas unveiled Wattway®, its version of the technology marketed as a photovoltaic road surfacing concept. Solutions from other companies are the SolaRoad® bike path in the Netherlands, and a Solar Roadway® prototype in the States.

It might come as a surprise to learn that Ifsttar is pleased the technology is being bought to market by others. One can’t help but wonder why the state-funded institute didn’t take out a patent it in order to cash in on its efforts. Have they missed out on a golden opportunity? Not so, clarifies Ms Jacquot-Guimbal.  Rather than patenting, our interest lies in French companies taking the innovation further to do business both at home and/or abroad, and consequently pay taxes to the French government. Our system of valorisation is based on public service principles, she adds

In any case the work is far from over for the researchers, who are henceforth focusing on extending the concept to optimise the energy captured, combining electricity and calories; to ensure every aspect of the road is as practicable as its standard equivalent; and also, importantly, establish a final cost will favour uptake.


During COP21 in December 2015, French environment minister Ségolène Royale announced an ambitious plan to install 1,000km of solar panel roads nationwide by 2020. Good news for Colas! We could cover 8 to 10% of the French highway network per year, points out Ms Jacquot-Guimbal, who is keen to see test sites up and running this year, in order to see what does and doesn’t work.

Lesley Brown





Transports passionL’association pour la mobilité durable et l’énergie embarquée