How much does it increase friction and would this be feasible on other vehicles as well? Once electric cars are eventually here, their wheels will be the primary noise emitters.
When we are talking noise terrorists with car mods added specifically to pollute the audiosphere, that is different ofc.
Our joint use of the public streets is based on a certain trust that drivers will not try to plow into people. That doesn't mean you have to recklessly abandon all precaution, but it does mean that there are always going to be edge cases that are unmitigated. I think the vehicle based terror attacks have sadly illustrated that point.
Walking the streets in a defensive mode that assumes low speed sneaking up by a driver intent to kill, or being completely oblivious to the surrounding, while at the same time driving a vehicle with defects in its core functions feels like an edge-case. The near ubiquity of people walking or cycling with headphones, or fully being fully engaged with their mobile phones seems to support that.
Cars are dangerous and operated without proper care for sure, but there are very, very few injuries from ultra low speed collisions with cars.
On the other hand there is enormous evidence of serious stress caused by traffic noise having an impact on health.
The whole 'car noise' thing was lobbied by car-makers hoping to cash in on a 'custom ringtones for cars', modeled after the mobile phone market of the 90's. Do you believe that these random noises will avoid more deads and injuries than those created by the resulting stress and 'postal' incidents by those having to involuntarily suffer this?
There are better options. Have slow moving cars emit a low powered radio or radar signal instead. Very compact and extremely low cost detectors and emitters already exist for those. Those that wish get a proximity warning without harming innocents, and as a added bonus this also works for people with reduced hearing, either because the have a hearing problem, or because they are wearing headphones.
The only ones that would suffer a tiny bit are the car makers missing out on selling sounds. Can't say I'm very sympathetic to that crowd as they have amply shown a lack of responsibility and care for people's health and well-being . As usual, the benefits they want to pocket are once more blatantly oblivious to the societal downsides as they have been fully externalized for them.
This is singularly the worst idea I have ever heard in my life
I was talking with a blind guy a while back about the beeping crosswalk things and he was saying he had to quit walking to the corner store because the intersection didn't beep and he almost got run over too many times since he had a hard time figuring out which direction he was able to walk by listening to the car noises alone which near silent cars would only exacerbate. Probably be easier to make all the crosswalks beep instead of forcing cars to make unnecessary noise pollution but until that time...
What's changing is the internal structure and suspension.
I'm not an expert on this stuff, but I would be surprised if it were as efficient as a normal wheel when on flat ground. The vibration study page states they will publish numbers on the rolling efficiency of the wheel 'soon'.