4 ms·

I challenge this opinion. If you have any ressources to back your claim, please share! My estimates for the velocity where tire noise will be substantially lou

I challenge this opinion. If you have any ressources to back your claim, please share! My estimates for the velocity where tire noise will be substantially louder than the rest of the car are much higher, more like 60km/h.

foepys 10y ago
It is surprisingly difficult to find an English source for this. [1] shows on page 3 a significantly higher tire noise for 50 kph (+8 dbA) but doesn't show lower speeds than 50 kph. [2] is in German and from the Austrian Federal Environment Agency and states that for cars build after 1996 25 kph is the point where the tire noise takes over at a steady speed and at 50 kph when the car is accelerating. 1: http://www.asphaltroads.org/assets/_control/content/files/anintroductiontotire-pavementnoiseofasphaltpavement.pdf http://www.asphaltroads.org/assets/_control/content/files/an... 2: http://www.umweltbundesamt.at/umweltsituation/laerm/laermschutz/massn_strasse/reifenlaerm/ http://www.umweltbundesamt.at/umweltsituation/laerm/laermsch...
- dolguldur 10y ago
  Thanks! The various components of tire noise are interesting. One other thing that came to my mind is that tire noise is usually concetrated in the high frequencies, whereas some cars, especially trucks, emit very low-frequency noises. The latter penetrate walls and windows much more easily. Of course tire noise won't go away with electric cars, but in my opion there's a vast underestimation of how much quieter roads and cities could be without combustion engines.
mschuster91 10y ago
Even if it's 60 km/h that won't help you much, as the average street in a German city has a speed limit of 50 km/h, and driving 70 km/h only gets you a 35€ ticket, so many people drive 60-70 and pay the odd ticket. Also, with truly autonomous vehicles, travel speed would likely be increased in order to maximize capacity - like it's done with trains, where both speed and minimum distance are chosen for maximum capacity.
- the8472 10y ago
  with autonomous vehicles you do not need to increase speed to gain capacity, you can already reduce the safety distance since the vehicles have a much lower reaction time than humans. And energy efficiency decreases with higher speeds due to air resistance, so saving energy (reducing load on the grid from charging) is also a competing concern.

foepys 10y ago

It is surprisingly difficult to find an English source for this. [1] shows on page 3 a significantly higher tire noise for 50 kph (+8 dbA) but doesn't show lower speeds than 50 kph. [2] is in German and from the Austrian Federal Environment Agency and states that for cars build after 1996 25 kph is the point where the tire noise takes over at a steady speed and at 50 kph when the car is accelerating. 1: http://www.asphaltroads.org/assets/_control/content/files/anintroductiontotire-pavementnoiseofasphaltpavement.pdf http://www.asphaltroads.org/assets/_control/content/files/an... 2: http://www.umweltbundesamt.at/umweltsituation/laerm/laermschutz/massn_strasse/reifenlaerm/ http://www.umweltbundesamt.at/umweltsituation/laerm/laermsch...

dolguldur 10y ago
Thanks! The various components of tire noise are interesting. One other thing that came to my mind is that tire noise is usually concetrated in the high frequencies, whereas some cars, especially trucks, emit very low-frequency noises. The latter penetrate walls and windows much more easily. Of course tire noise won't go away with electric cars, but in my opion there's a vast underestimation of how much quieter roads and cities could be without combustion engines.

mschuster91 10y ago

Even if it's 60 km/h that won't help you much, as the average street in a German city has a speed limit of 50 km/h, and driving 70 km/h only gets you a 35€ ticket, so many people drive 60-70 and pay the odd ticket. Also, with truly autonomous vehicles, travel speed would likely be increased in order to maximize capacity - like it's done with trains, where both speed and minimum distance are chosen for maximum capacity.

the8472 10y ago
with autonomous vehicles you do not need to increase speed to gain capacity, you can already reduce the safety distance since the vehicles have a much lower reaction time than humans. And energy efficiency decreases with higher speeds due to air resistance, so saving energy (reducing load on the grid from charging) is also a competing concern.