The European Parliament has just voted a text which will mandate all road vehicles to make less noise. Obviously, this sounds like a good idea. Millions of Europeans are living close to an highway or a busy street, and they suffer everyday from road noise. Even if Europe is already leading in that area (to the best of my knowledge, there isn’t a federal limit on exhaust noise in the U.S.). Actual requirement is that passenger vehicles must not be noisier than 74 decibels. The Parliament said this limit must be lowered to 68 dB. OK, fine. All the technologies to achieve this goal are already widely available. A Mercedes S-class or a Lexus LS are incredibly quiet cars, because they have a lot sound-deadening materials and large low-revving engines. The real issue is how to make a quiet car cheap and light.
Carmakers have recently invested a lot of money in small downsized engines, which is fine for efficiency, but a four-cylinder will always be noisier than a V8. This must be said clearly, lowering the noise limit will be the most difficult for the cheapest cars on the market.
Ironically, the Parliament added that if too much noise is no good, no noise is dangerous. So it calls for the introduction of an acoustic warning system on electric vehicles. And this could come quick. The new limit for lowering the noise should not be mandatory on new cars before 2020 at best, but it might take only 3 years for the noise-making device to be legally required on EVs.