France on the road to a quieter life

A noise barrier for roads developed in France is at least 30 per cent more effective than existing technology, its inventors claim.

Developed jointly by researchers from the French engineering school Ecole Polytechnique and road safety equipment specialist Colas, the innovation recently won the Siemens prize for applied research.

The barrier’s design is based on studies which show that irregularly shaped objects with jagged or ragged geometrical shapes are poor resonators and therefore better at deadening sound than those with smooth surfaces, according to Colas project leader Jean-Claude Roffe.

However, irregularly shaped objects present more of a manufacturing challenge, so the team focused on developing an acoustically absorbent material with a shape that would be appropriate for moulding.

Made of 50cm2 panels, the barrier combines a surface consisting of cone and pyramid frustums with wood-cement concrete. A frustum is the remainder of a pyramid or cone whose upper section has been cut off by a plane parallel to its base.

Roffe said that the panels can be designed in a variety of shapes and colours, enabling the barrier to blend into the surrounding environment. He added that, as well as being suitable for use on motorways, the barrier could also be used along high-speed railway lines.

On-site testing of the barrier, which costs around E190-200 (£130) per square metre, is now complete, and the system will be installed on its first road in France early this year. Roffe added that the company is also pursuing opportunities across the rest of Europe, including the UK.

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