Noisy e-cars: Do we need more noise protection zones?
New measurements in Switzerland show that e-cars can often be just as loud as combustion engines. Experts recommend noise models for forecasting and targeted introduction of traffic measures.
Greener and cleaner on the road. E-cars are often considered the mobility type of the future because of their environmentally friendly drive. But electric cars can also have problematic aspects that are usually seen in cars with petrol or diesel engines. Measurements conducted in Switzerland show that electric cars are not as quiet as many assume.
On two stretches of road, once in town and once outside of Aarau, noise specialists measured the noise produced by different car models. These included an older vehicle, SUVs, sports cars and various electric cars. The measurements showed that a Tesla X at a speed of 50 kilometres per hour produces a similar noise level to, say, an Audi RS6 with 600 hp. Results that are not too surprising, according to the experts. "The Tesla X is a big, heavy car with wide tyres and these tyres generate rolling noise," explains noise specialist Dejan Milo.
As the tyre industry already knows, road noise is precisely due to rolling noise. For noise, they can even be more important than engine noise, as in the example of the Tesla. "Up to 20 km/h, the engine noise is decisive, above 20 km/h only the rolling noise," Milo explains. Electric cars are therefore significantly quieter than petrol cars in residential areas, but on main roads this difference is no longer audible.
The study, conducted by specialists from the cantons of Aargau, Baselland and the federal government, confirms that the noise problem will remain unsolved in the future despite electric cars. The aim of the measurements was to bring clarity to the phenomenon and in the process collect data that will later be developed into noise models. These should then help in the planning of roads and noise protection measures, such as whispering surfaces or speed reductions.
The Swiss cantons are in fact already considering which solution would be best suited to cushion the effects of noise pollution on the population. The canton of Aargau, a role model for the installation of low-noise pavements, sees whispering pavements as the cheaper and more effective alternative to noise-protection windows and walls. Speed reductions and the possible effects of introducing a 30 km/h speed limit on cantonal roads are also being examined. In the meantime, tyre labels have already been mandatory in Switzerland since 2014. They reveal not only expected energy efficiency and safety, but also noise information.
With regard to the increase in the number of e-cars, especially in Europe in connection with the ban on the registration of combustion cars from 2035, the question of noise pollution from electric cars is also becoming increasingly important in other countries. Developments from Switzerland remain to be observed, as well as the results of the use of whispering pavements and speed restrictions. However, the introduction of new noise zones, both as an extension of the already existing ones, might prove to be the most stringent but also the most effective measure.