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Science Technology

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."
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Making Quieter Highways

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  • Side effects. (Score:3, Interesting)

    by Unknown Poltroon ( 31628 ) * <> on Wednesday August 13, 2003 @12:37PM (#6686994)
    How will this affect stopping distance? Probably better. But ill bet it dosent last nearly as long as regular pavement.
  • Tires _in_ the roads (Score:4, Interesting)

    by bill_mcgonigle ( 4333 ) on Wednesday August 13, 2003 @12:47PM (#6687138) Homepage Journal
    the pavement is simply asphalt with some mixed in rubber

    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 [] with galvanic reactions from the ground-up radial belts.

    Does anybody know if they've solved that problem?
  • Rubberized Asphalt (Score:3, Interesting)

    by Radical Rad ( 138892 ) on Wednesday August 13, 2003 @01:03PM (#6687341) Homepage
    I read about rubber chunks in asphalt before. Supposedly it lasts longer because when water gets in the nooks and freezes it would normally bust up the surface but with rubber there it gives so pot holes don't form as easily. Another benefit is that using these types of asphalt gives us something to do with old tires that normally sit in a landfill somewhere collecting stagnant water and giving mosquitoes a place to breed. If we can lay a mile of this stuff for $325k instead of concrete or cheaper asphalt but save $2M per mile on sound barriers then that seems like a pretty hot ticket.
  • by n1ywb ( 555767 ) on Wednesday August 13, 2003 @01:09PM (#6687423) Homepage Journal
    The color of asphalt is pretty interesting. It's always nice and black when they lay it down, because of the tar. But after 8 years or so, a lot of the asphalt they use in Vermont turns to a sort of dusty reddish brown color. It doesn't look so pronounced from the road, but from the top of the mountains looking down it strikes you as odd that it's such a light color. Must be the tar wears away and reveals the color of the gravel used to make it.
  • Whoosh! (Score:5, Interesting)

    by tickticker ( 549972 ) <tickticker@[ ] ['gma' in gap]> on Wednesday August 13, 2003 @01:10PM (#6687442) Journal
    I live near the sections of highway where they have laid this stuff, and it's like pulling a nail out of your head when you hit it. The constant hum of the road is much more intrusive then you can imagine. It's alot like turning off the range hood fan after it's been on for a couple hours and the hum has invaded your bones. All you hear is the wind around the vehicle.

    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

  • by jilles ( 20976 ) on Wednesday August 13, 2003 @01:13PM (#6687477) Homepage
    Yep, in the Netherlands this kind of thing is long past the testing stage. My country is pretty densely populated and has quite a few highly congested highways. We have standards for sound levels which have to be met. This has created a financial incentive for road constructioners to research solutions to reducing the noise and meeting those standards.

    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.
  • by drivers ( 45076 ) on Wednesday August 13, 2003 @02:20PM (#6688186)
    I'd be willing to bet that the noisiest highway surface in the country is I-5 in Seattle. I'm not talking about the expansion joints (much of the surface is elevated) but the fact that the concrete has been eroded into visible ruts so you are driving on large chunks of rock. It's deafening inside the car. I recently drove 1200 miles and back (each way) on I-90 and found no section as noisy as that in Seattle. Apparently the problem is studded tires during the winter. It's funny how you see all these old people in the giant cars driving around with studded tires in the winter months even though there's no snow here.
  • by The J Kid ( 266953 ) on Wednesday August 13, 2003 @02:24PM (#6688214) Homepage Journal
    Actually you should be more worried about it takes to soak into the new asfalt...

    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)

    by Anonymous Coward on Wednesday August 13, 2003 @03:34PM (#6688745)
    I've been driving on a Caltrans rubberized asphalt road nose trial section of I-280 (Woodside CA) for about a year now. It's been great for dropping noise levels, but I want to see what the noise level of this section of road is at the end of its life span.
  • Harmonics (Score:3, Interesting)

    by quinkin ( 601839 ) on Wednesday August 13, 2003 @08:54PM (#6691075)
    An issue I have never seen addressed by the tire manufacturers is the issue of harmonics.

    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 .


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