While it might sound deafening, traffic noise is actually a feeble source of energy. The 100db roar of a passing lorry generates barely a hundredth of a watt of power per square metre. By way of comparison, sunlight is tens of thousands of times more concentrated, producing about 680 watts per square metre.

So it’s better, then, to harness the kinetic energy produced by traffic as it moves over the road surface, and supplement this with solar panels in the road – together these energy sources could feed into the grid, or even charge electric vehicles as they drive along.

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