Making Quieter Highways 137
An anonymous reader writes "Researchers at Purdue are investigating ways to make life for those who live near major highways more quiet. They have found that most of the noise is literally where the rubber hits the road, not engine noise or even passing winds. The team has come up with a new form of pavement that is in testing in Arizona and will soon be installed in California. The pavement is simply asphalt with some mixed in rubber."
Side effects. (Score:3, Interesting)
Tires _in_ the roads (Score:4, Interesting)
Disposing of tires by making them into roads has been a dream for recyclers and probably the tire industry, but last I heard they had some major problems [s-t.com] with galvanic reactions from the ground-up radial belts.
Does anybody know if they've solved that problem?
Rubberized Asphalt (Score:3, Interesting)
Re:They've only just figured this out? (Score:3, Interesting)
Whoosh! (Score:5, Interesting)
I look forward to hitting the stuff, and they are supposed to be repaving a 21 mile portion of a highway thats not even 3 years old yet. (The highway system in Phoenix is still pretty new and growing)
I don't need a sig
Re:They've only just figured this out? (Score:5, Interesting)
A combination of sound deflecting shields in populated areas and better road surfaces is pretty much standard for roads nowadays here. My parents live about 1km from a very busy highway and while you can hear some noise in the background if it is really quiet (like at night) it can barely be heard.
Noisiest highway in the country (Score:3, Interesting)
Allready been done... (Score:3, Interesting)
Anyway, new tarmack has allready been invented ( to be quiet, yes). It's called ZOAB (Zeer Open Asfalt Beton, which means Realy Open Asfalt Concreet). It's nice airy mix of asfalt & concreet which reduces the time for rain to soak in, making it a lot safer to ride on in heavy rain & is quite a bit quieter..
There are also newer versions that are even quieter, but so far only ZOAB is use on almost all the dutch high-ways.
I wish these people would just combine their efforts instead of staying in that NIH (Not Invented Here) mode.
Old News (Score:1, Interesting)
Harmonics (Score:3, Interesting)
If a wheel has 50 distinct nodules/strips of tread pattern, and is rotating at 264rpm, then it will produce a tone at around 220Hz (or concert pitch A).
If tires were constructed in a less repetitious tread design - perhaps a log periodic or goedel sequence - then it would help eliminate these stray harmonics .
Q.