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Science Technology

Making Quieter Highways 137

Posted by michael from the drive-less dept.
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 More

Making Quieter Highways

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  • Side effects. (Score:3, Interesting)

    by Unknown Poltroon ( 31628 ) * <unknown_poltroon1sp@myahoo.com> 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.

    • Re:Side effects. (Score:3, Informative)

      by Cy Guy ( 56083 ) *
      Yeah, the article sites the cost of repaving at "$325,000 per lane mile." whic makes me wonder a couple of things, how long will that last until repaving, what is the per year cost of maintenance (pot-hole repair, re-striping, etc.), and WHY THE HELL DOES THE CONGRESS THINK AMTRAK SHOULDN'T BE SUBSIDIZED?

      Sorry about yelling, but seriously, If AMTRAK needs a $3B/year subsidy that is 1500 miles of 6 lane highway - or about the cost to repave I-95 North to south.

      • Where do you think we are? (Score:4, Insightful)

        by BoomerSooner ( 308737 ) on Wednesday August 13, 2003 @01:21PM (#6687567) Homepage Journal
        Europe?

        Seriously though I agree completely with your statement. However, common sense has long since left our government.
      • Comment removed based on user account deletion
      • 1. If you repaved I-95 from end to end, it would last a lot longer than the subsidy Amtrak is requesting.

        2. For a real eye-opener, try scheduling trips on Amtrak between the various cities served by I-95. A friend of mine recently bought into the concept of the "romance" of trains, and subsequently tried to schedule a trip by rail from the West Palm Beach area to Atlanta. By car, this would be a single long day's drive. By plane, it would be a two hour flight. By train, the fastest route available require

        • P.S. Yes, I know Atlanta isn't on I-95. Which probably brings up another good point, 4. Amtrak doesn't (and can't) serve remotely as many locations as I-95 does today.

    • Coefficient of friction (Score:5, Informative)

      by n1ywb ( 555767 ) on Wednesday August 13, 2003 @01:03PM (#6687353) Homepage Journal
      From http://www.hronline.com/forums/ohs/0109/msg00073.h tml

      The coefficient of kinetic friction of rubber on rubber is listed in this

      source as Natural rubber, vulcanised at 100m/min on rubber flooring or
      rubber tread vulcanisate, clean, - 1.16. That's pretty high!
      That IS pretty DAMN high! The coefficient of friction of rubber on dry asphalt is around 0.6 or 0.7, which is already considered to be pretty high. So logically, adding rubber to asphalt would probably improve the coefficient of friction between the tires and the road, hence decreasing stopping distance and improving cornering.

      Physics is the study of everything.
      • Any ideas about fuel efficiency? It seems to me if the road is causing more friction, there must be more power used to move the vehicle.

        • This is stopping friction. Your Tires are Rolling across the pavement when you're driving, and thus not really subject to that. The friction during driving comes from your bearings in the engine, air friction, etc, it's all internal to the car. This increase in stopping friction will really only effect stopping and cornering, to their improvement.
          • "Your Tires are Rolling across the pavement when you're driving, and thus not really subject to that. The friction during driving comes from your bearings i"

            There is plenty of friction involved from the normal tires rolling on the road too. This is what heats up the tires, and causes wear and loss of material over time.
        • Not necessarily. One thing that we overlooked was the difference between static and dynamic friction. Static friction tends to be much greater than dynamic friction. When two bodies are stationary against each other, you've got static friction, EG a tire rolling down the road. Dynamic friction is when two bodies slide against each other, EG a tire skidding on the road. So since the friction between the tire and the road is usually static, it shouldn't really effect efficiency much since at the contact patch

          • the contact patch the tire is actually stationary relative to the road.

            I wonder if it really is.

            Just as you mention, the tire does flex and deform as it comes into contact with the road and as it leaves contact with the road (warm tires after a high speed drive confirm the viscous dissipation during such flexing).

            I'd be inclined to believe that smooth roads with very low dynamic friction coefficients would enable better gas mileage because then all expansion and contraction of the contact patch could b

          • Rolling friction would be drastically increased, which would improve braking as the parent stated, but would KILL fuel efficiency.

            Consider trains: Steel on steel to minimize rolling friction; dump sand on the tracks when you need to stop, and increase the friction. Trains are optimized for operating conditions, not the end conditions.

            The upshot however is that you could have the same net friction by reducing the width of the tires. Of course, you could only stop per specs on the special pavement, but
      • I live in phoenix, they've done this to a part of the I-17 (near 19th ave).. The road is so nice to drive on, so quiet and the handling on it is prime for going 100 at 3AM (though there's probably 6 or 7 fatal crashes at any given moment, just because the drivers here are totally retarded).

        they're doing the SR-51 next, but they're taking their sweet time doing it, at this rate I'll have graduated from ASU before they finish it and make my commute more bareable.
      • So logically, adding rubber to asphalt would probably improve the coefficient of friction between the tires and the road, hence decreasing stopping distance and improving cornering.

        I belive this phenomenon is the reason why new brake pads need a "break in" phase--to embed the pad material into the nooks and crannies of the metal disc surface. The rationale, I suppose, is that pad-on-pad is better than pad-on metal.
      • That's for clean rubber-on-rubber. Add some dust, sand, or dirt in there, and I'm sure it goes down a whole lot. It's also for generally flat rubber (flooring or tread) - change that for asphalt-like texture and you'll have crannies for the dust to flee to (so it stays out of the contact area), but you'll also change the whole surface interaction.

        cool info, thanks.
      • The major counter to this argument depends upon the increased elasticity of the "collision" between a portion of tire tread and a portion of the road.

        If the elasticity is increased such that a mild rebound effect is produced, this will decrease the effective friction. However, I would not expect this to be a major issue.

        In addition, I would expect the initial friction to be of higher importance than kinetic friction for standard (i.e. not emergency braking with wheel lock) driving conditions.

        Q.

      • Improve cornering...great...now, anytime a SUV changes lanes too fast, it'll flip.

        Seriously though, this will be bad for a lot of tall cars. Cars are designed to slide instead of flip. If you nearly double the grip, your gunna have a lot of cars that can potentially flip now.
    • Actually you should be more worried about rain...how 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 dut
      • I wish these people would just combine their efforts instead of staying in that NIH (Not Invented Here) mode.

        Americans can be stubborn. I guess that's why men in South Carolina still have sex with pigs and goats, because new ideas about women came from North Carolina. Please don't ask me where babies come from in South Carolina, because I just don't know...nor do I want to know.

  • I hope to god they succeed (Score:3, Insightful)

    by PeteyG ( 203921 ) on Wednesday August 13, 2003 @12:44PM (#6687100) Homepage Journal
    I lived next to Interstate number 5 last year, and it was like a constant dull roar coming in through the windows. After living for years in the quiet peace of Alaska, it was quite a shock.

    If all the noise is from the rubber hitting the road. We need magnetic cars!
  • They tear up the roads and lay down new pavement every nine months or so anyway, right? Might as well make it quieter when they aren't working on it.

    Alex.
    • 9 months, maybe where you live in, most places its closer to 5 years.
      • I spent four consecutive years in one neighbour hood while attending uni.

        Each year I moved house one street further away from the uni, and each year at final exam time they would scrape the top of the road for resurfacing.

        It would take a good month for them to do one street, and the noise was truly horrendous.

        If a solution is found to this noise then I will be impressed. :)

        Q.

  • They've only just figured this out? (Score:5, Insightful)

    by gazbo ( 517111 ) on Wednesday August 13, 2003 @12:45PM (#6687121)
    On the A31 near where I used to live there is a stretch that is done in a noticeably darker (and smoother) tarmac. I think it was done specifically for noise reduction, and when driving over it you can really tell - it's a tremendous difference. Like you know if you're in a room with a washing machine and it finishes, and suddenly you're aware of how quiet everything is? Same sort of effect.

    Now I'm not saying it's the same stuff, but is it really a new finding that it is the tire/road contact that's noisy when this was done at least 6 years ago?

    • 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.

    • Re:They've only just figured this out? (Score:5, Interesting)

      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.
      • The stuff the poster is talking about is called actually a kind of asphalt mixed with stones to make it very open. Another nice property is that it allows water to go through. This means that the roads do not get wet when it is raining, and there is no water being slashed by big trucks. The only problem is that the top layer freezes quicker when temperatures are low. And that it is more easily damaged by flat tires from trucks. Appearantly, most drives do not notice the flat tires, as sometimes the tracks r
    • Like you know if you're in a room with a washing machine and it finishes, and suddenly you're aware of how quiet everything is?

      Or in a datacenter when the power goes out!

      Joe
    • Having just completed a 4200-mile roadtrip, I can attest to the dramatic differences in road surfaces. There's a particular stretch of I-70 that drops to, I believe, 35MPH for a few miles. The pavement also changes, and becomes unbelievably noisy. I wonder if the intent was to emphasize your speed, and increase the "reward" for slowing down?

      Going from state to state, or county to county, you can tell that different contractors use different mixtures and surface preparations. It's utter bliss to experience

      • Going from state to state, or county to county, you can tell that different contractors use different mixtures and surface preparations.

        Down here, where I live in North Carolina, we have an area called the Sandhills. The whole area is little more than one big sandbar. Asphalt in this area is much more abrasive than in most other areas, and can increase tire wear. This is most noticeable to NASCAR fans. Rockingham Motor Speedway is paved with this high-sand-concentration asphalt, and that track is kn

  • 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 [s-t.com] with galvanic reactions from the ground-up radial belts.

    Does anybody know if they've solved that problem?

    • Re:Tires _in_ the roads (Score:3, Informative)

      by pmz ( 462998 )
      last I heard they had some major problems with galvanic reactions from the ground-up radial belts.

      I would imagine that it wouldn't be terribly difficult to build a process that removes ferrous materials from rubber. Melting all the rubber and sticking a big magnet into the goo is one thing that comes to mind. I believe one other metal used in tires is brass, but that shouldn't be as prone to corrosion.
      • Melting all the rubber and sticking a big magnet into the goo is one thing that comes to mind.

        Vulcanization of the rubber cross-links the polymers which means that it will not melt anymore. If you raise the temperature enough it will only burn.

    • That link refered to tires used a fill under the roadway:

      From this article [uswaternews.com]: ...the recycled rubber is piled to a maximum depth of 27 feet on a 4-foot gravel bed, topped with 3 feet to 5 feet of soil.

      What's being proposed is a modification to the asphalt - more of a surface treatment.
  • This should make construction companies happy, as they find a new reason to tear up streets just to lay down new asphault. Of course, knowing how New York City works, someone will notice 2 mos after the 4 year project is complete (of course over budget), that the 'new' asphault is actually the old asphault... Such is life.
    • I live in the Chicagoland area where the two seasons are winter and construction. Our roads are regularly ground down to their component elements and reconstituted in a shoddy manner that necessitates their annual replacement.

      I can only assume that this pattern will continue indefinitely rubber in the roads or not. It should be business as usual for the shovel-leaners around here.

  • liars and thieves (Score:3, Informative)

    by passthecrackpipe ( 598773 ) * <passthecrackpipe@@@hotmail...com> on Wednesday August 13, 2003 @12:48PM (#6687160)
    A similar compound was invented in the Netherlands ages ago, using concrete (cheaper and easier to handle then rubber). It is called ZOAB ("Zeer Open Asfalt Beton", meaning "Very Open Asphalt Concrete") This highly porous material has several beneficial properties, such as being more quiet, and more efficient in draining water, thus preventing aquaplaning. It is a safer road, alltogether. Now some university is passing this off as a "Great American Invention"?!?!

    Same thing happend with airport groundradar. A Norwegian Company invented a groundradar system for airports, allowing safer manouvering of aircraft in dense fog and other low viz situations. This delivered tremendous safety to airports. The FAA wanted it, but it had to be american - can't buy of those eurotrash companies and all that. 8 years down the line, and it still was not working. In the meantime, you have had about 33 near misses at o'hare alone.......

    Obviously I shall now be modded down -50 "unpatriotic eurotrash bastard" whatever.
    • liars and thieves

      That's a pretty strong statement. But you can't support it with facts.

      A similar compound was invented in the Netherlands ages ago,

      That's nice. How does the compound developed in the Netherlands differ from the one developed at Perdue? If you don't know, I humbly suggest you put your flamethrower away. For all you know, Perdue's compound is better, cheaper, or works in a wider range of environmental conditions. At any rate, none of this constitutes lying or stealing.

      Now some uni
      • I'm not flaming, not at all. And yes, you are right. "Liars and Thieves" is a strong statement I cannot directly support. However, if you read the article, specifically the bit at the bottom (in the yellow block) then you would note that the bit at the bottom states:

        "Even though European countries and some U.S. experts have suspected that different pavements can lower ever-increasing highway noise levels, researchers are the closest they've ever been to a viable, and more cost-effective solution. While en
        • Call me paraniod, but it seems to imply "researchers have been breaking their heads over this, both in Europe as well as the US, but they are not yet sure. In US (hence, "Great American Invention") we are already way ahead

          I don't call you paranoid. But I think that any reasonable reader will see that you are way hypersensitive. In my opinion, the article didn't imply anything negative about any other country. In my opinion, your interpretation of the section you quoted is incorrect.

          I don't know where
          • "Your sig is irrelevant to the context of our discussion, but I'll just mention in passing that the quote you have there is in reference to allowing doctors to smoke in hospitals. Yeah, sorry, we don't allow Iraqi doctors to smoke in our hospitals."

            We don't allow Iraqi doctors to smoke in *our* hospitals? Yarmuk Central Hospital in Baghdad? That's not your hospital, unless the US now owns Iraq. Guess that makes it clear where you are coming from.... And while we are contextualising my sig [guardian.co.uk], you may read t
            • You may brand me an "anti-american eurotrash fool, full of hatred" and all that,

              You're definitely full of hatred, and it has obviously colored your perception of the highway-noise article and our discussion of it. I have *not* called you eurotrash or a fool however. You have used those labels several times yourself though and it's interesting to me that you evidently have deluded yourself into believing that I am calling you eurotrash. It's symptomatic in my opinion of a persecution complex. You think
    • it had to be American - can't buy of those eurotrash companies and all that

      Well, they are the country that invented the NIH (Not Invented Here) syndrome...

    • Maybe if you got the giant chip off your shoulder you could be a little more objective. Where in the article (did you even read it?) did it have the words "Great American Invention"? (hint: nowhere). Let's be honest: the article is a fluff piece. It gives few details on why tires on existing roads make noise and the research being done at Purdue to solve it (no claim that the reserach was exclusive to Purdue). Are you actually claiming that the Dutch system is noiseless? Great! We can just license it

  • duh (Score:2, Informative)

    by greentree ( 682982 )
    of course it's the rubber hitting the road. here in michigan the road commission made a serious mistake in implementing a "new" type of cement that was supposed to last longer. however, it turned out it didn't last long(er), in fact it did the opposite. and worst of all it had rivets perpendicular to the tires moving over it creating an obnoxious howling noise. i've seen more the one local news coverages on pissed off people living nearby highways that have to put up with terrible noise pollution.
    • What stretch are you talking about? I remember MDOT talking about I-375 using an experimental type of cement, and it appears to be holding. More recently, I-275 was "grooved", resulting in a reasonable reduction in noise.

      I just wish they'd fix M-14 WB west of Plymouth.

  • 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.
    • the sound wall will last for decades, or until the highway gets widened again. how much more or less long will the highway last when paved with asphalt mixed with rubber? repeated repavings is a cost that needs to be considered too.
      • A valid point. The article I read was many years ago and if I recall correctly it was something like: the rubberized asphalt would cost twice as much but last 5 times as long. This article lamented that there are laws which force the contractors to take the lowest bid which meets the minimum spec so it was not possible to even experiment with the new materials here in the US. Howver it mentioned that the materials were being tried in several places in Europe with good results.

  • I just saw this on TV (Score:3, Informative)

    by KurdtX ( 207196 ) on Wednesday August 13, 2003 @01:06PM (#6687385)
    I don't quite remember the night, but I saw it on tv recently, and it kind of got me thinking.

    Now I've got a sports car with some noise dampering, but generally I can hear everything. The nice thing is it's shaped really smoothly, so I hardly get any wind noise, so just about all the noise coming in from outside my car is from the road. The thing I notice is that even with current roads (I live in San Diego), the biggest difference is on the ones that are concrete - since they don't buckle like asphalt-covered ones do. Sure, I've noticed that some of them have grooves, which is where I suppose the air is going (and to help with skidding in the rare event of rain) - those ones seem to be the most quiet. But even those get loud if they're not graded right.

    Hey, think about it, most of the time a car is fairly quiet, but when you go over a bump, your car is usually louder after you land and reach the minimum point. The other thing I'd say is that maybe it's due to the weight of the vehicles, as there's a huge difference between cars and SUVs/Trucks - and motorcycles are silent except for their engines. So maybe the solution is to stop selling SUVs... yeah, I'll keep dreaming.

    • Silent motorcycles (Score:4, Funny)

      by AtariAmarok ( 451306 ) on Wednesday August 13, 2003 @01:46PM (#6687870)
      "and motorcycles are silent except for their engines"

      Yes. Just like dead fish has a pleasant odor, except for the smell.
    • Yeah, I noticed that on my new motorcycle. With stock pipes and a windshield I could hear the clutch engage when I stopped, even at highway speeds the noise from the cars around me was much louder than the wind or the bike.

      Of course I realized this was a safety hazard (to me) so I put on loud ass pipes so that even the most insulated SUV can tell I'm coming. Loud Pipes Save Lives man.

      • You must ride a cruiser...

        Loud Pipe Piss Off Man Who Is Neighbor. Hope none of your neighbors involved in local/national government policy making.
      • ... so I put on loud ass pipes so that even the most insulated SUV can tell I'm coming.

        No, they can't hear you coming, but they can hear you leave. Loud pipes are only loud beside and behind you, not in front. "Saftey" is a lame excuse for some macho show-off BS.

  • Whoosh! (Score:5, Interesting)

    by tickticker ( 549972 ) <tickticker@gm[ ].com ['ail' 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

    • Or you could just build the roads like they did up north... Squaw Peak is nice and recessed, with the nifty looking patterned concrete walls that deaden sound. I know that when Tucson redid I-10 they tried to use the same technique wherever possible. Also helps to keep a nice seperation between "surface streets" and the freeway system.

  • Still recyclable? (Score:4, Insightful)

    by Xunker ( 6905 ) on Wednesday August 13, 2003 @01:21PM (#6687570) Homepage Journal
    One thing the article doesn't touch on is reusability. One thing that the paving industry likes to pride itself on is that asphalt is almost totally recyclable. However, to my understanding, dense rubbers (such as car tires) aren't reuasable in that way, they can't be melted down and reused with reliability. Would the addition of the rubber have a problem with the recasting of the asphalt? With the amount of repaving that happens every year, what sort of effect will this have on the waste output of a repaving operation?
    • I think it might be re-usable, I took a look at what the guys in my village were doing when they recovered a road nearby, and asked, as the road had a very crimsony look to it (which faded to light grey). They said that it is some kind of mixer added to recycled materials (the old road i guess).

      To me as a layman, it looked a lot like the 'soft' they put on top of kids playground's in school (like a bouncy layer of rubberised tarmac), a covering over an existing base, it is much quieter to both drive over a

  • in canada... (Score:3, Informative)

    by xilmaril ( 573709 ) on Wednesday August 13, 2003 @01:40PM (#6687776)
    I guess it's different in the states, and possibly elsewhere, but in canada (or at least the handful of cities I've lived in), they've been using rubber in pavement on busy streets for years.
    • in Canada... (Score:3, Informative)
      by xilmaril [slashdot.org] (573709) O [slashdot.org] on 01:40 PM -- Wednesday August 13 2003 (#6687776) [slashdot.org]
      (Last Journal: 04:42 AM -- Wednesday August 13 2003 [slashdot.org])
      I guess it's different in the states, and possibly elsewhere, but in Canada (or at least the handful of cities I've lived in), they've been using rubber in pavement on busy streets for years.

      Capitalize that 'C' man, show some national pride! :-)
  • The pavement is simply asphalt with some mixed in rubber.

    Well, then won't there be more rubber touching the road??

    • Technically, the road will be more.. rubbery. The sound is rubber hitting the current mix of asphalt. They are shifting the asphalt a bit towards more rubber to make it less noisy.

  • Rubber Roads? Nice! (Score:4, Funny)

    by Hell O'World ( 88678 ) on Wednesday August 13, 2003 @02:02PM (#6688019)
    Its one more step towards mankind's ultimate dream , bouncy world! Car crash? No problem, you're in bouncy world! Airplane fly into a building? Boing! Ha, Ha, Ha, everybody OK!

    • Its one more step towards mankind's ultimate dream , bouncy world! Car crash? No problem, you're in bouncy world! Airplane fly into a building? Boing! Ha, Ha, Ha, everybody OK!

      I don't know how or why, but the parent post inspired me to babelfish-recycle it through various languages just for fun. I have some karma to burn, so enjoy at my expense =)

      Chinese:
      It is more step toward humanity's final dream, has the elastic world! Traffic accident? Without the question, you are in have in the elastic world

    • Its one more step towards mankind's ultimate dream , bouncy world! Car crash? No problem, you're in bouncy world! Airplane fly into a building? Boing! Ha, Ha, Ha, everybody OK!

      It's even funnier if you imagine this being read by the Zombo.com [zombo.com] guy.

    • Remind me: why don't they make cars out of rubber?
    • Reminds me of the rubber bumper bar debacle.

      Engineers looking at the problems of car crashes decided it would be advantageous to have rubber bumpers so that cars don't smash into each other, but instead bounce "harmlessly" off each other.

      Unfortunately, this converted the energy that had previously been lost as deformation, noise, etc. into spring recoil energy...

      Consider two cars colliding head on, both moving at the modest speed of 10Km/h. Instead of each driver deccelerating from 10Km/h to 0Km/h in

    • You seem to be living in a dream world.

  • Noisiest highway in the country (Score:3, Interesting)

    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.
  • I swear, I-95 / 93 around Boston has the worst drainage and road surface of any major highway I've seen (but no, I've not driven around LA. :). When it rains, the water just mists above the surface rather than draining away, drastically reducing visibility in otherwise OK conditions. Plus, the lack of clear road markings on I-95/rte 128 make it a case of 'spot the lanes', especially at night in bad weather.

    Haven't they heard of reflective paint and cat's eyes? I pity non-local drivers exposed to those road
  • Rubber + water + rubber = Slip.

    Granted, in the dry it will have good grip.

  • The real problem is the fact that idiots continue to build and buy homes next to busy highways; airports too. If you don't like the noise, don't live there!

    • That certainly is a problem and I don't have a lot of sympathy for people who expect the state to install noise barriers because they decide to build a home next to a highway.

      But part of the problem (especially here in NJ where everything is becoming more congested) is that new highway construction or expanding local roads into larger highways is bringer traffic nearer to more homes. In this case I don't have a problem with putting a little extra expense into reducing the noise.

  • Fairly obvious if you ride bike (Score:3, Insightful)

    by sporty ( 27564 ) on Wednesday August 13, 2003 @03:15PM (#6688598) Homepage
    I don't mean a motorcycle either. Try riding a mountain bike at some decent speed. Eventually, at the right speed, it hums quite nicely.

  • Old News (Score:1, Interesting)

    by Anonymous Coward
    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.
  • Didn't some country have the bright idea to mix rubber with asphalt before as a way to recycle old tires? and didn't a car bursting into flames after an accident literally cause the road to catch fire?
  • Here in Rio Grande do Sul, Brazil, the Government is performing tests with this kind of pavement, made with recycled tires. Its only half a mile, and the diference is brutal...

  • 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 .

    Q.

  • I drive on a mile stretch of it that was put down in a test on my way to work here in Phoenix, and there is a 12 mile stretch on another highway here. Its quiet, safe, and no problems with braking or anything else. Its quite a pleasure to drive on
  • If you've ever driven to the Mall at Short Hills in northern New Jersey, you might have driven on a 1 mile stretch of this kind of pavement.

    A couple of years ago, Essex County paved the short stretch of highway that ran from Route 78 to the Mall at Short Hills with a "quiet" pavement. The difference is very noticeable. Much like the difference between driving on regular asphalt, and then hitting a patch of recently paved road, the "SHHHHH!!" sound you usually hear suddenly dims down to a low "wooohhh".

    O

    • Your title says rt 24, which runs by the Mall at Short Hills, but in your comment it says rt 78. I'm guessing you meant to say rt 24? Which side of the highway? East bound, west bound?
  • Look here http://www.silentroads.nl/index.php?section=produc ts for what is being used in the Netherlands. I read a 'discussion' about ZOAB, which was more like a flame war, that's why I don't post it as a reply. ZOAB is commonly used in the Netherlands, also because rain is removed from the surface quite fast, hence safer roads.
  • There's a stretch of highway in Buffalo that's been repaved in the past few years and that is so quiet and smooth, it feels like floating on air (almost). It's the northbound section of I-190 between a point somewhat north of Rt. 198 (the Scajaquada) and the Tonawanda GM Plant. I drive a sport-sedan with very sensitive struts and a set of rather quiet Michelin tires, frequently travel with the windows down, and I just love that ~1 mile stretch of road. You can actually listen to the radio while crusing at ~
    • Wait another 40-50 years...

      My hometown is Bakersfield, CA (stop laughing) - I-5 bypasses most of Bako, but you can go through it via highway 99. Now, highway 99 is interesting unto itself. It used to run a different route, on what is now called Union Ave (I think that is right) - or also known as "old 99". There is a turnoff off of 99 as you head north, I think just past the turnoff to I-5. Anyhow, old 99 is one of those things you have to see.

      It's a 4 to 6 lane highway, with huge eucalyptus trees flanking

  • Car horns blown by intra-city drivers. Is it really necessary to: - Blast your horn when you drive past someone you know? - Honk the very instant the light turns green to get people moving? - Honk again and again when pulling up to pick someone up, when all you have to do is get out and knock or call someone using your cell phone? - Or honk in front of a shopping mall or office building to pick someone up - surely you know that they either don't hear it, or can't distinguish it from regular "background h
  • 1. Jake brakes.

    2. Truck tailgates banging.

    Is anyone trying to develop quiet trucks? I sure hope so.

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