With the advent of electric vehicles, one might think that the noise pollution generated by automobiles is on its way out. Yet 80% of a car’s noise is generated by its contact with the road, and poor road conditions exponentially increase noise pollution both inside and outside the vehicle.
It’s with this in mind that Thomas Antoine, Expert Leader Noise & Vibration Technology at Renault Group, developed the Apache program, which maps road conditions to pinpoint areas where repairs would be most beneficial to decrease noise pollution, as well as the economic and public health burdens on local communities. Thomas Antoine and Fadila Hrird, a first-year master’s student in geomatics applied to urban studies and risks at CY Cergy Paris University, explain how this technology works, their methodology and describe the program’s many expected benefits.
For Thomas Antoine, Expert Leader Noise & Vibration Technology at Renault Group since 2018, the facts are clear: noise pollution is a major societal and environmental problem which he’s decided to reduce through his work and expertise. The numbers speak for themselves: according to the World Health Organization, 20 million Europeans complain about noise, and 8 million sleep poorly. While the Ademe, the French Agency for Ecological Transition, points to the social cost of road noise in Europe, estimated at 80 billion euros a year.
To combat on-board noise pollution (especially road and airborne noise), car manufacturers are increasingly relying on technology widely used in audio headphones: noise cancellation, which equips the Scénic E-Tech electric, for example. This noise cancellation is activated by sound sensors placed around the vehicle, which listen to the road and detect variations in road noise. When this increases, the sensors inject a sound wave into the cabin which evens out the sound spectrum in the vehicle, cancelling out the noise heard by passengers and making the journey on board far more pleasant. A manufacturer like Renault Group could leave it at that, but the company’s culture of innovation pushes its engineers to go even further.
“The Apache program is proof of our inventiveness. The problem of noise in the environment isn’t just a question of which car, which tires? It’s about how the car interacts with its environment.”
Thomas Antoine, Expert Leader Noise & Vibration Technology
The Apache program, or how to map road conditions
It was while studying noise cancellation sensors that Thomas Antoine wondered whether it wouldn’t be possible to use the signals they generate in a different way. The idea for the Apache program was born. Apache, an acronym for Appraisal of Pavement Acoustic CHaracteristics and Energy Efficiency, is a casing which analyses the road, like the needle of a record player, to produce maps of the acoustic condition of the road network. This data is then compiled to give a very precise analysis of where a road is in particularly bad condition and therefore noisy.”It’s a technology that not only improves the acoustics inside our vehicles, but also enables local authorities to make more accurate decisions about their road repair budgets. So, in fact, it’s a win-win situation for everyone,” explains Thomas Antoine.
To produce more comprehensive maps, Thomas called on Fadila Hrird, a work-study geomatics student who joined Renault Group as part of her masters program at the University of Cergy in France. Fadila uses a specific program to create maps with various layers of information, such as proximity to sensitive locations (schools, hospitals, retirement homes, etc.) to determine the level of impact a road may have on local residents.
“We get a tremendous amount of data from these sensors, but then it’s a question of transforming it into useful information. For these maps to be correlated with road use, we need to know how often the roads are used, and that’s where our partnership with Bruitparif comes in very handy.”
Fadila Hrird, work-study student specializing in geomatics, Renault Group
Partnership with BruitParif, the key to offering a complete service
Right from the start of the project, Thomas Antoine understood that this detailed analysis of road conditions could be a valuable aid to towns and communities for whom road repair strategy is a major challenge and a significant part of their budget. This will enable them to target very precisely the sections of road to be repaired. But for this analysis to be complete, one essential element was missing: road use. This data is crucial in determining the speed at which a road deteriorates, and the extent to which it generates noise pollution.
So Thomas Antoine contacted Bruitparif, the Noise Observatory for the Île de France region, which happened to be looking for more information on the acoustic condition of roadways. Bruitparif quickly joined the project, providing the necessary data and facilitating a test program in the Saint-Quentin en Yvelines area. It was a success, and the program has now been extended to the whole of the Île de France region, with some thirty vehicles equipped with the Apache casing criss-crossing the region’s roads. The project has now received interest from several cities in France and abroad. The Apache program is an innovation patented by Renault Group and has been awarded a Golden Decibel by the French National Counsel for Noise, the first time this has been awarded to an automaker since… Renault’s Vel Satis in 2001 !
The link between noise and energy consumption – the key data
Thomas and Fadila’s in-depth analyses have confirmed that there is a direct link between noise and CO2 emissions or range for electric vehicles. The Apache program is able to put a precise figure on the costs and environmental savings associated with road repairs, and even in how many days the cost of road repairs is offset by a fall in emissions. They have calculated that 1 euro invested in roads represents 17 to 20 euros saved on the social cost of noise. To give a concrete example, refurbishing the Paris ring road, the busiest road in Europe, would divide noise levels by around four, and after four years, savings would reach 16,000 tonnes of CO2 per year. For Thomas Antoine, this project is both a source of pride and a real change in his profession. By taking an interest in non-traditional areas of the automotive industry, it is possible to create new value chains for Renault Group. As for Fadila Hrird, who represents a new generation of engineers who have understood that technology can concretely solve problems linked to the environment, she is now looking forward to new artificial intelligence applications to process an ever-increasing quantity of data, which will make projects such as Apache even more relevant.
SOURCE: Renault Group
