How Highway Noise Barriers Can Make Traffic Louder - Cheddar Explains

Highway noise barriers are intended to reduce traffic sounds for nearby residents and businesses. And there are over 3,000 miles of these walls lining U.S. highways. However, recent studies show they might not work as well as intended. And could actually be amplifying noise in some locations.
Further reading:
Undark
undark.org/201...
Federal Highway Administration www.fhwa.dot.g...
Jalopnik
jalopnik.com/h...
Wisconsin Department of Transportation wisconsindot.g...
Smithsonian Mag
www.smithsonia...
Sound Walls
soundwalls.com...
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[@_ikako_]

As any City Skylines player will tell you, trees are the best solution to noise pollution. Not only do they have far more surface area to absorb sound over, they also have the added benefit of absorbing some of the pollution from the cars on the road.

[@welcomb]

That's what is done in my city. Trees and tall hedges line the highways. Even pedestrian pathways along major roads have vines too block the dust and noise.

[@_ikako_]

@@bingosunnoon9341 well the trees that line 90% of England's motorways seem to be doing just fine

[@mkviis]

Bro I just delete their homes if they nag about everything

[@vashishtshaurya]

@@mkviis I want you to be the mayor of my state

[@enterpriset]

Better leave it to the actual engineers then because in the real world it doesn't work. Studies (notably: Leonard, Raymond E., and Sally B. Parr. "Trees as a sound barrier." Journal of Forestry 68.5 (1970): 282-3) have found that even 30 meters of dense foliage will only drop sound levels by ~6db. Having to buy an additional 60m of right of way for a highway to plant trees, only for such a small impact is not as effective as other types of sound mitigation.

[@tbthegr81]

In Sweden, all noice barriers I see is made out of wood, and shaped in a way to try to catch and trap sound. Where each piece of wall is an S-shape, where I assume they aim to trap sound in the "boxes"

[@potto1488]

Here in Britain too

[@davidrubio.24]

I haven't seen many noise barriesrs here in Spain. But the only one that I can remember has the S shape too.

[@ARCGrayist]

The S shape is because Sweden starts with an S

[@davidrubio.24]

@@ARCGrayist That's why we also have them in Spain...

[@lourencovieira5424]

In portugal they are made of plastic and are usually transparent with bird designs on it

[@bgovetas]

Diffusion and absorption are the way. Reflections literally create an echo chamber. Physics are cool

[@FoxDren]

Definitely, a "green wall" of trees works wonders and is used in many countries. Also looks nicer

[@Mariet31]

Heck... even planting trees would have helped to absorb noise.

[@DonnaChamberson]

@@FoxDren how dare you

[@DMTHOTH]

this is why every other first world country has patterned thin wood/metal sound barriers, instead of concrete wall.

[@descoiatorul]

@@bingosunnoon9341 that's stupid and if you did any research on it, you'd know it too. Tree curtains are THE BEST way to cancel noise. If they are planted at the proper width and density, going from bushes to small trees and then taller trees to cover any vertical gap and they can cancel almost 90% of the noise. Also, a proper tree barrier protects not just from the sound, but will also protect the road from harmful weather, by trapping winds and snow. Furthermore, tree curtains were shown have another benefit: they reduce the severity of roadside accidents. When a car leaves the road and slams into a concrete barrier, it will most likely result in deaths. When a green barrier is installed, the car is slowed down by the vegetation before reaching the tallest and most solid trees in the back, thus reducing damages to the car and the severity of the impact. Last but not least, trees protect nearby residences from pollution. In addition to trapping cross winds, they also trap dust emanating from the highway. This is all common sense in Europe and has been used successfully for decades. The US is doing almost everything wrong because of corporate interests. After the initial planting, trees grow by themselves and maintenance cost in minimal. Maybe you will have to replant some bushes or trees after accidents, but that's it. Meanwhile concrete walls make a lot of money for the politically-connected contractor, while having all sorts of negative environmental impacts: they amplify noise through sound deflection and reverberation (sound waves trapped between two barriers are amplified), they not only stop dust but create more, they are an eyesore, etc...

[@sabikikasuko6636]

So basically, concrete is so convenient that even after it's been proven that it not only doesn't work, but it makes the traffic noise *worse* and more deafening, the state won't do anything because doing so is a pain in the ass. Yeah, sounds about right.

[@nietur]

As politician, explain to everyone why you won't do anything against the sound pollution.

[@bcubed72]

Even if it is louder when installed (And TBH I don't find "online journalists" UnDark reliable)...let the vegetation grow over it, and it will prevent this phenomenon. The Kudzu will quiet it down in a year or so.

[@TheKitMurkit]

Should have made cones on the barrier

[@TheAvsouto]

New infrastructure is mostly subsidized by federal money, but reparing/maintaining/removing old infrastructure is paid almost enterily by the city and a bit by county/state. Most cities are not flooding with money so they opt to not do nothing to not go bankrupt

[@jackgerberuae]

@@TheKitMurkit please explain more?

[@NotJustBikes]

Huh. I was just researching a video about urban noise. This is good timing!

[@Flagen579]

Hey, if it isn't my favourite (not just) bike infrastructure channel!

[@sanchises]

Have you seen the noise barriers on the A2/N2 Eindhoven ring road? They're made of perforated tubes that are supposed to dissipate the noise energy. And they're very pretty

[@gus4198]

It’s the algorithm. You should watch “the social dilemma” on Netflix

[@paschadoudou]

Just bikes

[@intensivecareunitpee5838]

it's called data harvesting and tracking

[@c182SkylaneRG]

Sooo.... what about trees? Plant a good 20-30 ft thick row of trees, make sure they're a fast-growing, dense-foliage species of evergreen. They take care of themselves, they're soft so they absorb the noise, and the dense foliage and 20-30 ft thick row makes sure that there aren't large holes for sound to pass through. Drivers get something green to look at, instead of grey, residents get something green to look at, instead of grey. Road noise isn't refracted over the barrier, it isn't reflected back on cars, and we get a 1st stage filter on all the C02 being produced.

[@Nilsy1975]

Plus trees would filter out particulate matter and other pollutants.

[@StLouis-yu9iz]

I like your idea but I think there should be some broad leaved trees mixed in with the evergreens. Even though they wouldn’t look as good in the winter they are still better at absorbing greenhouse gases.This would be even prettier too.

[@DSQueenie]

They’re expensive to maintain. You’d need gardeners to trim them every day in summer.

[@Nilsy1975]

@@DSQueenie we use trees as sound barriers here in the UK.

[@henrydavis4236]

@@DSQueenie What trees grow so fast they need to be trimmed daily?

[@nixboox]

This is exactly what happened by my house. The side closest to the road needs to be made to look like recording studios with sharp pointed angles to break up the soundwaves instead of just flat surfaces for the sound to bounce off of and spread out.

[@jim-7965]

yesss

[@nadeemnajimdeen5717]

I think many of them are. Just that not all counties and state govs have used them.

[@florichi]

Cones would diffuse the sound, but not trap/absorb it. Most sound barriers in Austria are either made out of long strains of wood waste glued together to have cavities in it (like the porous asphalt they were talking about in the video) or sheet metal cases with tiny holes in them and some sort of absorption material in it. Only a minority of the barriers are glas or flat concrete walls.

[@TMS5100]

this is exactly what they are doing with newer barriers.

[@additionad]

Trees work better.

[@AustinMeltonADM]

Agreed. I live a few hundred feet from the interstate. Thankfully there are plenty of large mature trees that make the sound all but disappear. It’s a bit more noticeable in the winter though.

[@bryntownshend6528]

They look nicer and are less susceptible to vandalism than a concrete wall too

[@bryntownshend6528]

As are mounds of earth which can look more natural as well

[@TheAvsouto]

It's also a lot nicer to have trees around rather then having concrete walls to stare at

[@vicgamesvt9682]

The issue with this is you have to layer trees and with how little space their is between the highway and house there probaly isnt enough space to get enough layers of trees.

[@danielantoniozd26]

I grew up near a major hwy, even at 200 feet I could still hear it. Now I need it as whitenoise to sleep. I don’t like a quiet house at night.

[@jgroenveld1268]

@Evil Pimp I wish I could do that. I used to struggle with any noise or light source. Now what I have managed to do is that I learnt to sleep with white noise in this case my fan to drown out others noises especially voices that prevent me from sleeping. Light is still an issue for me so anything with as small as standby lights on tvs for example I would apply a little dab of electrical tape to block the light.

[@jeffreyanderson1851]

Sounds like the ocean

[@solidsnaker1992]

kids provided me immunity to sound while asleep lol

[@brandonaynesmay352]

Geez some people need quality sleep. No offense :D

[@jwhite26]

Thanks for sharing

[@mcmurdo75]

Trees and bushes combined make for the best sound barrier and they have environmental benefits like cleaner air

[@TomUniverse]

Good idea.

[@Gnefitisis]

Very bad idea. You don't want trees near fast moving cars. Because you don't tend to bounce off of them during accidents.

[@jasperschlief]

@@Gnefitisis don't you have a normal steel barrier, and then in the background for the noise cancellation some nature

[@maggiejetson7904]

@ They absorb like a sponge, but as @Gnefitisis said you will die if you hit it rather than bounce off.

[@captainspongeboy]

Acoustic Engineer here. Trees and bushes don't work. Sound is like water, it finds its' way through any gaps. Trees and bushes have huge gaps and so do almost nothing to reduce sound. There is an ISO standard that says that the attenuation through a wooded area is only (on average) 0.02 dB/m! Although, trees can provide masking by rustling in the wind.

[@Lunavii_Cellest]

in the netherlands we build hills out of earth next to highways to have reduced noise whilst it looking better and also working better

[@CT-vm4gf]

That’s great, if there’s room.

[@CapnCody1622]

In the US we don’t care what’s better. Only about what’s cheaper. Not saying that’s how it should be. It’s just how it is…

[@DSQueenie]

Unfortunately that takes up a lot of space.

[@babo2303]

Also the road surface is very different in the Netherlands. Almost all highways have this porous asphalt (what the guy was talking about) which reduces noise 🤗

[@_ikako_]

there's also that park that was built to counteract the frequencies of sound from a nearby airport that the residents were complaining about

[@murdelabop]

Not building interstate highways through residential areas would probably also be a good idea.

[@jarynn8156]

Those residents need to be able to get around though. Ultimately, you are going to need major roads near residential areas because those residential areas are what creates all the traffic.

[@VanganPL]

@@jarynn8156 That traffic doesn't need to be on a single road, and doesn't need to be at fast speeds. Leave the highways outside of the city and most of the problem will be solved - people will drive through multiple smaller roads to get to their homes, rather than having their homes cut off from the rest of the city by a highway...

[@JaneDoe-dg1gv]

How about using higher density residential zones to make public transport cheap enough to switch to, even with automobile and oil subsidies keeping car prices artificially low.

[@PAYTONLB999]

@@VanganPL you understand that doesn't work. Right? Phoenix didn't have a ring road until very recently, and it had some of the worst traffic ever. It had exactly what you said and had far worse traffic than cities much much larger than it

[@_ikako_]

@@PAYTONLB999 more, and more efficient, public transport infrastructure would do way more to curb traffic than more and bigger roads can.

[@minion2702]

typing from nottingham uk. trees and hedges they do exactly what you need them to do, look pretty and reduces noise

[@The_-_-]

More cost effective too

[@maggiejetson7904]

@@The_-_- Not really if you factor in the landscaping cost.

[@BossInvader1]

@@maggiejetson7904 But not $2,000,000.00 ( 0:19 ) per mile to maintain unless its all Bonzai trees or something I can't think of that would cost that much to maintain.

[@Vale-nh6ey]

@@BossInvader1 that isn’t to maintain, it’s to build

[@nicolaim4275]

I think natural sound barriers are easier to use in Europe because we generally have climate more suited for life. A lot America is too hot and too arid.

[@philplasma]

Highway, then train tracks, then thin row of trees. That's what I have to deal with; no concrete noise barrier and apart from when the engine part of the train passes the noise I get from the highway and the train tracks are well within my comfort zone.

[@trainsandmore2319]

@@c182SkylaneRG That's what you always see in Singapore's East Coast Parkway

[@morfgo]

haha where do you live

[@cmontes7961]

Move!

[@ToryFromDC]

Sounds like near Washington DC

[@trainsandmore2319]

@@ToryFromDC for me probably near LIRR

[@far574]

I used to own a house a couple homes next to the freeway. Since we were on a hill you could not see it. Pretty everyone that came to my house would ask where is the river ? It sounded like a running river. I am happy I no longer live near the freeway.

[@dragorocky]

Ours sounded like ocean waves. Interstate-15 North County San Diego.

[@insectbite1714]

@@dragorocky California cars make extreme amounts of pollution so your health is at risk too.

[@AtomicSource11]

Ahh, you would have just been getting the low.frequency sounds that have wavelengths longer than the wall was high. They can pass over the wall as if it's not there

[@55oblivion55]

The different types of asphalt/"pavement" make a HUGE difference. We have two types here in Germany. If a highway (Autobahn) section needs to be replaced, they use the "new" less noisy type. You will notice the severe change in noise when driving from the old road onto the new one. Its less than half the noise at least, as far as I can tell.

[@santiagoescobar6239]

Maybe the ussage of trees will do the same intended purpose but also improving air quality... don't know why it is not used already

[@itsnotmily]

because you're assuming trees will do a good job of reducing noise based on nothing?

[@jarynn8156]

@@itsnotmily Sound is vibrations. Absorb the vibrations, absorb the sound. As the video explains, the problem with sound barriers isn't the wall itself, its the material its made of. A hard concrete wall bounces sound. Soft materials absorb it. So a tree line would absorb the sounds.

[@eliscanfield3913]

@@itsnotmily Well, which is noisier, a bare room full of hard surfaces or a room with carpets, furniture, and drop ceilings?

[@santiagoescobar6239]

@@itsnotmily based on that trees does have a lot of surface and moving structures and does serves as buffer barriers due to dampening the movement because the are flexibles contrary to what happends with concrete. Check it up, there are cool and interesting proyects around the globe like what is happening in South Essex www.forestresearch.gov.uk/tools-and-resources/fthr/urban-regeneration-and-greenspace-partnership/greenspace-in-practice/benefits-of-greenspace/noise-abatement/

[@yvrelna]

Trees does have the disadvantage that it requires much more maintenance then a simple concrete wall. Cleaning fallen leaves, trimming branches that obstructs the road, replanting trees uprooted by tornadoes, tree diseases, culling to prevent unwanted reproduction, etc. Often, there's even perverse incentives to use less effective solutions because highway constructions are often federally funded, but maintained by local governments, so the local government would very often opt for the low maintenance solutions even when it's not cost effective solution overall if you include the construction cost.

[@thomaswalsh4552]

“Depending on distance, noise can reach 70-80 db at 50 feet” nice contradiction on the opening line

[@nicolaim4275]

It was probably an edit. "depending on the distance, noise can reach very high levels. It can reach 70-80 db at 50 feet".

[@jb6712]

For almost 3 1/2 years (Oct. 2017 - Feb. 2021), I lived in a dump of an apartment that was only 400 feet from one of the busiest freeways in the US. No barriers of any sort---not even a skinny hedge---to block the sounds, and the noise level was constant, loud, and hard to bear. My sleep suffered hugely for it. Moved to my current apartment In Feb. of this year; now the same freeway is about half a mile away, and there are numerous business buildings, as well as a small apartment complex of two-story buildings, between it and my place, and these buildings run perpendicular to the freeway, so any sound from there is mostly deflected back to it by those buildings. The only time I really hear it now is when the wind blows from the north---from the direction of the freeway---and it blows the sounds of the freeway between our buildings. It's so rare, it's not a problem, though. Then, only about 1/4 mile behind the apartments, we have a train track on which about six freight trains a day travel; again, though, not much of an issue---none, really---partly because they go through so quickly, and partly because there are a lot of trees and low, one-story buildings between the tracks and this complex. The engineers also don't get crazy with sounding the train's horns, using them appropriately for the 3 or 4 crossings near here, so again, not offensive. It's amazing, though, how moving back off the freeway by half a mile, and having those buildings (and some mature trees, though not more than a dozen) makes such a huge difference in sound. Now it's peaceful, and often downright quiet here, which I'm so very thankful for! My sleep quality has improved so much, I can't even compare it to the other place.

[@krisP16]

I noticed this in the small town I grew up in. There was a railroad track going through town in a deep trench. When the train would sound it's horn it would be extremely loud and annoying. I always wondered why they didn't just put the train tracks on level ground. Also, the house I live in now has the highway noise problem. We are 150m or 492ft from the highway barrier and the sound is deafening at times. Honks, sirens and street racers can be heard as if they're right outside our house. I hate being outside in the afternoon especially when trying to have a conversation.

[@CharlV]

In the Netherlands, there are glass barriers at some locations in the city. It's also angled and not 90 degrees. Don't know much about it but it seems very effective. They also use a lot of greenery and it seems to help as well.

[@julesjames593]

I've live directly across the street from a freeway exit noise wall. I was there before the wall was built. Its installation has been a game-changer. We can now have a sidewalk conversation. Of high significance is the message a noise wall sends: "This is an area to protect, please respect neighbors with lower speeds, quieter music and less litter." I-5 at Roanoke Street in Seattle -- the busiest stretch of highway in the Pacific Northwest. From experience: I support noise walls.

[@stevemc01]

"You have become the very thing you swore to destroy."

[@DougGrinbergs]

Noise control: reflection diffusion, diffraction absorption

[@lourencovieira5424]

In portugal they are made of plastic and are usually transparent with bird designs on it

[@Malusdarkblades11]

Where i live they use Earth walls they work well and get nice and green over time :)

[@tcsnowdream9975]

Yea, I lived near the chuo expressway in Tokyo and they used green barriers - lots of plants and trees in addition to the sound barrier. It looked nice and I barely heard anything.

[@guardianoffire8814]

Ba Sing Se has earth walls made by earth bending....

[@MilwaukeeWoman]

I'm not sure if there's a version of that useful where we have cold and snowy winters. Snow that has salt mixed in with it gets plowed right up to the wall, that would kill plants. There are houses right on the other side of the wall. I think concrete is the best we can do. I'm a block away and the sound might be louder for me because of the wall, but I knew that when buying the house and I find the white noise comforting. I can also hear trains. Lots of life around here, it's nice if it's your thing.

[@emmamemma4162]

@@MilwaukeeWoman We have those earth walls in Finland, snow and salt is not a problem.

[@TdaKraakGaming]

The A7 highway in The Netherlands has a wall of dirt retained by steel skeletons with plants growing by side of it as a sound barrier. It truly works as it’s being reflected Bach to the road because of its shape and absorbed by the plants and dirt.

[@judithp8552]

Walls of dirt or mounds that are higher than the highest truck seem to work okay. A mound of dirt running the length of the house and as high as the roof of the house on the highway side. Netherlands and Germany are advanced in noise reduction for the health of people living in nearby highway residences...

[@Lorryslorryss]

I mean, the whole building huge highways everywhere is an initially attractive, but ultimately terrible and unsustainable idea that the American have been continuing on with regardless. So it seems noise barriers fit quite well with the rest of what you're doing tbh.

[@PAYTONLB999]

Ring roads and highways reduce traffic for large American cities

[@rachelle2227]

As opposed to what? Public transport? Railroads, the best long distance public transport, is not realistic to be built to work for most US residents. The country is enormous, with so much open space. The money that would have to be laid down to even connect Chicago to LA, for instance, would be staggering.

[@kazimir8086]

@@rachelle2227 wtf? Everyone else has already done it.

[@JoCE2305]

@@kazimir8086 "Everyone else" (Europe) lives in a country the size of Texas with higher density. You underestimate the size of America.

[@davidrubio.24]

​@@rachelle2227 Highways are okay for traveling between cities. The problem is when they are used to move around the city (instead of having a more dense city with public transport). That's when you have highways next to residential areas.

[@doe_maar365]

In the Netherlands the sound barriers are placed at an angel, so the reflections are directed to the sky. this method is way more expensive since the foundations of the barrier has to be complex, but it's effective

[@drink15]

The barriers are already there and unlikely to be removed but they can be improved by adding bushes and veiny plants to grow up the wall. This should soften he wall and absorb some of the noise.

[@cookieridergirl]

I’ve seen wood barriers around where I’m from. Not sure if they are any better than concrete. Imagine maybe they absorb more sound. But still. Maybe put some trees there. I get perhaps it’s because the trees will take years to get to a good size. But if they had started back in the 70s it’s would have been effective by now. Probably last longer than a concrete wall. Looks better too for everyone involved.

[@szeptacz5342]

Trees would only work during warm months. No leaves - sound

[@marklaw5116]

@@szeptacz5342 plant evergreen trees. Problem solved.

[@MilwaukeeWoman]

@@marklaw5116 evergreen trees drop a lot of branches and many of them also pinecones. This would cause road hazards and also great expense cleaning up after them. Source: live a block from the freeway and have evergreen trees on my property.

[@marklaw5116]

@@MilwaukeeWoman all conifers drop cones, but not all evergreen trees are conifers. There’s a huge number of evergreen tree species that don’t drop cones, especially in warmer climates (California and Texas would find it very easy to grow evergreens along their highways). But even in higher Katy it uses there are non-conifer options, such as live oak.

[@TheFantasyReason]

Cheddar always answering the questions in the back of my mind.

[@stephenpowstinger733]

I studied road noise years ago. What I found was low-frequency sound waves are tall and need a tall wall to stop them. It also helps to have texture on the wall or strategic grooves. The permeable road surface sounds like a good idea as it may help drainage as well.

[@thefigg88]

The highway by my parents got a noise barrier installed... for a cemetery and long stretch of wooded area.

[@ernestbywater411]

The most effective noise barriers ever provided are earth and trees. Not only do they properly break up the sound they absorb a lot of it, and they last a hell of a lot longer than concrete while also being much more environmentally friendly. Even if all they do is plant native shrubs along the verges of the highways they'll find they'll have a decent reduction in road noise.

[@catcameron2495]

Cheddar always interesting. What about growing ivy, or something, up the walls? Or, idk, hedge rows. to help absorb sound.?

[@ScoutyDave]

In Sydney they put a lot of plants, trees, and vines on the walls to absorb sound. Also it helps with air pollution.

[@РусланШкуренко-ц6у]

What's with audio?

[@varsityathlete9927]

interesting, i always thought it was the engine noise, and as electric cars become more common the noise level will just drop.

[@infidellic]

I think that's what I thought when I was younger, then I've had to replace tyres/tires at the side of a motorway/freeway twice since and rapidly learned that the sound is completely wrong and it's clearly mostly tyres.

[@CleverAccountName303]

It will make it quieter because instead of having engine noise and tire noise, electric cars have only tire noise. Low speed areas such a city centers and intersections will be much quieter, but the difference on the highways will not be noticeable because tires are so loud.

[@Squaretable22]

i think about 40MPH/70KPH is where it crosses over, before that its mostly engine, after its mostly tire/tyre. Freeways are all tyre, while City Streets are mostly car engines.

[@varsityathlete9927]

@@Squaretable22 that makes sense, electric cars are quiet when they drive past, but its always at slower in city speeds.

[@brianleeper5737]

Where I live it's usually exhaust noise because the first thing a nephson does when he gets a truck or motorcycle is to straight-pipe it.

[@nik_evdokimov]

I live in Finland, and here often I see mounds of ground - looks nicer, more eco-friendly and is a soft material

[@Edhilues]

In Korea, some of those walls are 5~8m tall and are covered with vines, it will clearly have more efficiency to reduce noise and look better.

[@buddy1155]

@Lee Corin Maybe in South Korea, in the north Korea, no vines but barbwire.

[@daelbows5783]

We should build industrial areas around highways instead of residential. Industrial areas can deal with the highway noises, plus it will benefit the trucks that need to get places.

[@robertkent4929]

Physics pretty much disproves their use. My acoustics I professor in college suggested planting trees and installing a fountain in your back yard. Your ears acclimate to the sound and if your eyes see something else that makes constant noise (like said fountain) you can trick your ears into believing the sound is coming from that

[@frankhusel5033]

I doubt that this really helps. I remember working and living places that had such fountains. It wasn't relaxing at all, but downright nerve-racking. Much too loud when the sound is trapped between the walls. Believe me, it won't work.

[@mkviis]

Tunnels and tall walls are amazing, when I go through one with my four cylinder car, it sounds like a screaming v6 😂

[@gerardcurtis3911]

in the UK I've seen lots of wood fencing, I imagine its a lot cheaper and more absorbing, but also they're not a flat line, so then the sound gets reflected randomly, being quieter

[@watermeloninsideawatermelon]

okay but you could also just reduce the amount of vehicles by massively improving public transport especially in large and medium-sized cities, that would already make a big impact, be environmentally friendly and also give people social mobility.

[@cityplanner3063]

Noise barriers are effective if the materials use absorb the sound. Build it just out of concrete will reflect the sound. We learn this in first year city planning.

[@hughfergusson9544]

We just need to start reducing our highway needs.

[@Boxhead42]

What a very simple solution to an incredibly complex problem. 🙄 Lol. If it was only that easy......

[@Tadfafty]

United States of America, doing that?

[@samwalko]

I live near the end of a cul-de-sac, and then there's a wall then the 8-lane interstate. However, the interstate is also in a bit of a valley, which seems to help direct the sound up rather than just over the wall. Inside with windows closed, it's quieter than a desk fan, honestly. Outside or with windows open, it's still much quieter than a conversation.

[@wownewstome6123]

Yeah, sunken freeways sound like the way to go! I lived and shopped near one and it was fairly quiet, despite having a lot of fast, thick traffic, including many otherwise loud trucks/semis.

[@Chantillian]

3:10 - 50 ft, 100 ft, 200 ft, then 200 ft again...? I blame the viewers for not supporting Cheddar enough to hire a better editor. ;)

[@doctordothraki4378]

I was looking for someone else who noticed that exact goof

[@somitomi]

I have never in my life seen a sound barrier made of bare concrete. Sound barriers here are usually covered with cement-bonded wood chippings creating a porous surface. They're usually pressed into a corrugated shape to further diffuse and absorb sound. Sound absorbing panels made of wood and glass wool are also common along motorways.

[@FinancialShinanigan]

This is why we need underground tunnels and more open space for people and nature

[@dave_407]

“A wall MIGHT make traffic louder” “One man in Florida claimed his house was quiet before a wall was built “ That’s some hard hitting investigative journalism there

[@jarynn8156]

Awful audio quality, not very informative... Feels like the channel has been letting its quality control slip lately. Still some good stuff, but quite a few wastes of time too.

[@TriAngles3D]

Many North Western Europe highways do not have barriers that are perpendicular to the road but instead set at an angle. Also, many are made of more absorbent materials. I would assume that concrete is highly reflective and that the height of the barrier should not be a multiple of the dominant low frequency sound wavelength that tires produce. In particular, these low frequency signals can bend around corners. While they are self-canceling in certain regions they also become amplified in other regions when they collide such as described in the video.

[@brokengoose]

As with most Cheddar videos, bumping the speed to 1.25 helps with. The. Slow. Narration. Speed.

[@lachlansmart2373]

I live in Brisbane, QLD, Australia. I have driven extensively around the eastern mainland between Bundaberg and Melbourne. The vast majority of all noise barriers that I have seen are metal uprights (Stainless steel I might guess) with treated timber slats horizontally between them. Often, there will also be a row of trees on either or both side/s of the barrier as well.

[@Andrewhedgehogs]

Soil walls seem pretty effective to lower noise pollution from motorway 🛣.

[@boriss.861]

If you are going to put up a concrete wall, a wall that is shaped like an egg box and tilted towards the roadway should reduce the noise as the shaped zones will reflect and cancel noise and the tilted wall will direct the residual sound back to the source

[@doujinflip]

I noticed in Japan their noise walls are curve into the road at the top, which might help lengthen the deep sound shadow behind the wall

[@yutgoyun]

I just sold my condo where I’m right next to a freeway. So glad to be moving. I can verify many of the effects described in this video.

[@leszz]

I thought it was so cars wouldn’t go crashing into houses, stores, etc when there were to be a accident or something

[@jeremyandhannah2235]

Makes sense. I grew up in SOCAL next to a major freeway, there was always that constant white noise, but when I visited a friends house who’s backyard was up against the 20’ tall freeway wall, It was noticeably more quiet than my house which was about 6-7 houses away from the freeway.

[@mbogucki1]

Always appreciate the metric conversions. Cheers from Canada.

[@jamesalias595]

Noise pollution is a serious problem that the government ignores. They might do an initial study but then have other projects that greatly increase traffic and they don't take this into account of all the traffic changes over a larger area. Sound walls are not sufficient. They should pay for sound proofing existing homes.

[@darkless60]

5 mins video in 4 words: concrete hard reflect sound

[@schnutzudri918]

...if they are built the wrong way. As they do in the US. Not sursurprising at all.

[@katel3962]

We live 1.2 miles away from I-64 in St Louis County, Missouri. There are NO barrier walls and we easily hear the highway traffic all night, despite multiple subdivisions and a park between us and the highway.

[@joshuagabsart]

I’ve always thought they were there to annoy the passengers views of the scenery, but I later learned it was for lessening noise pollution.

[@joostglas5631]

Lol what😂

[@tondriasanders6306]

I live in a rural suburb, in a small track of homes, surrounded by grassy dairy land. I am within 1 mile of a four lane state highway, with out a sound wall and I can not hear the highway. However I used to live on one of the dairies. It was three miles away from the highway, without a sound wall, and I could hear the freeway every night.

[@alexanderosullivan9764]

Wait until you hear that these barriers can bend over the road like in Asia! Then they might work better

[@coastaku1954]

My middle school was about 1km south of the QEW, a highway that has a noise barrier at that section, yet I could still hear the loud drone from it, clear as day

[@finn2828]

Or maybe we could just use less cars in general

[@iniciusv1]

tons of money to buy cars, to build infrastructure for them, to fix the problems they generate and it still doesn't work well

[@N911GT2]

In the Netherlands we have very silent asfalt on our highways. It’s called ZOAB and ik really makes a difference. Also we typically grow plants on our barriers that helps a lot too.

[@ex0stasis72]

That’s so interesting! Now I want to see a video about that from Not Just Bikes. That sounds like it’s right up his alley for what his channel is about.

[@lucasmatson]

please buy a better microphone, your videos are so well edited but the audio really makes them a lot worse

[@FGH9G]

Agreed, combined with the sub-par sound mixing at times, the narration can often times be unintelligible.

[@frostburnspirit9065]

There's something wrong with the audio in this specific video and I don't know what it is, but it's so bad I can't watch it. All other videos are fine, what are you talking about?

[@lucasmatson]

@@frostburnspirit9065 i think its just bad mixing but ive noticed the quality isnt really good in some videos. id imagine shes recording from home and doesnt have access to cheddar's recording equipment

[@SCIFIguy64]

I lived about a mile from the interstate. 8/12 months, you couldn't hear anything because the wood was so dense. But in the winter, when the leaves fell, you could hear vehicles far away. It wasn't loud, but it was noticeable late at night. It's kind of odd, being almost on farmland, and hearing a truck engine brake before an exit on a snowy night.

[@blusterlumino890]

when you live in a condo and your condo is the noise barrier for the housing area behind

[@funnyfarm5555]

Our house was built in the 1930's (About 25 feet from the road) and at the time the road was dirt/gravel and little traffic, had 90% corners so slowed traffic. (We have been here 28 years) The road (Springhill DR/'Springhill Raceway', Albany Oregon, 7.5 miles long and wanders cross country) now has increasingly over the years become a shortcut for commuter traffic, Farm equipment, trucks, log trucks and Semi's because there is a stoplight at the south end end in town and they cannot get on the other east-west highway 20 further west because of increased traffic. Now with the road being pavement and having being built on a poor base it has needed to be torn up and redone for several years. The county's solution was to chip seal (tar and gravel) it multiple times. Well chip sealing a road makes it much louder. Talking to the county, we were told that it would be repaved in 2018. Well here we are in 2021 and all we have gotten is grinding out strips where the road has breached through the pavement and putting in new asphalt (by the county crew, not well trained pavement workers) while they have repaved from milepost 5 into town twice. They also come out after every rain storm and fill in the blowouts on the last 2.5 miles with temp patch. So we can definitely attest to the noise created by different pavement types, potholes, improperly patched roadway, loud muffler cars, certain motorcycles, mud tires on pickups, trucks, log trucks, semi's, farm equipment Etc.

[@LFTRnow]

Car tire noise from roads and (and freeway) noise is not much of an issue. It comes out as a hiss sound. However, the #$!@! that insist on making their vehicles' engines as loud as possible and then relish in making that noise - THOSE are a pain, and there are way too many of them. On-ramps are bad, as are intersections for this. Used to be thumping stereos, now it's roaring engines.

[@emmamemma4162]

In Europe this is illegal (at least in some places). Best law ever!

[@nagranoth_]

In the Netherlands it's common to use earthworks as sound barriers. These are bound to be softer than concrete and thus absorb more of the noise, I also don't see how anything can be more durable than landscape. Keep it covered in grass so it don't erodes and it'll never have to be replaced.

[@seasong7655]

The solution is to completely enclose the highway or build it underground

[@London755]

Or, hear me out here, not build the highway. Most new highways serve little purpose other than to facilitate more suburban sprawl.

[@seasong7655]

@@London755 true but the ones, that are already built need to be removed as well

[@JaneDoe-dg1gv]

Solution. Switch to railroads.

[@PAYTONLB999]

@@London755 suburban sprawl exists because suburbs are safer and more desirable than cities... and because people keep wanting to move further from the city

[@muzzthegreat]

The choice of concrete is surprising - it's much more expensive than pressure-treated plywood, or pine boards - hmmm, maybe the concern is vandals burning it? Here in Queensland the wood is often in panels that are separated by steel - usually a universal-column - a fire wouldn't propagate very fast. The wood is often green [copper napthanate] so the wall 'disappears' behind a few shrubs - and the Main-Roads-department is obsessed about planting shrubs - every shrub you plant eliminates another bit of grass to mow - and if someone crashes off the road shrubs will slow them down before they hit something hard.

[@trivmtran]

It's maintenance cost. Concrete doesn't need to be replaced as often as plywood.

[@Snuzzled]

I thought those walls were for safety, to help reduce cars from careening off highways accidentally, as well as preventing pedestrians from wandering onto highways.

[@TheArtstuff]

I live near a main road without a noise barrier. This video focused on tire road noise, however that is rarely the problem where I am except for heavy trucks. Overly loud exhaust from cars and trucks and motorcycles are the real problems we face.

[@DaxxterDreams]

Plant plants on them. It is cheap, looks good and reduces sound a lot

[@MilwaukeeWoman]

The plants make the very expensive walls deteriorate faster. Concrete construction is polluting. This is a very bad idea.

[@vikingstrong5772]

This doesn't work.

[@frostnotm5282]

Most countries: Let's plant trees, shrubbery and soft barriers Americans: LETS BUILD A WALL

[@Fernando-ek8jp]

Depending on the distance you can have x decibels at 15 ft. Nobody else see a problem here 😂?

[@bcubed72]

No, I don't. For purposes of standardization you measure "how noisy a thing is" at a fixed distance. Otherwise, you can play games with how far away you are to hide data: measure a rocket launch at 500mi, and it's pretty quiet.

[@ronnieam33]

In Phoenix we use rubberized asphalt that is asphalt that has used car tires ground up in it and it makes the road so much quieter for everyone and helps will water drainage when it rains.

[@nunya___]

@5:08 "Concrete walls have to be replaced every 30 years or so." Really, you seriously think that? LMAO

[@cubiusblockus3973]

The buried pillars that hold up the wall degrade due to moisture and concrete cancer, if they are not replaced, the wall has a risk of collapse.

[@Salattrainer]

In Germany a women died because a concrete wall fell on her car.

[@nunya___]

@@cubiusblockus3973 Being that I'm well versed in building construction but not this construction in particular, I say that _that's_ only due to poor construction standards/materials. Concrete rot and metal degradation are due to poor maintenance and material selection. Properly protected steel such as galvanized steels of adequate gauge would not fail in 60 years or more. Concrete walls, with regularly applied sealant (5 to 10 years per application), would last indefinitely given that all concrete will soften with age but very capable of hundreds of years of service. I'm very much in favor of natural berms and trees but in tight urban areas it can't be _the_ solution. Concrete can be protected by natural oils and with thin wood (that's vegetation bearing) if preferred. Also, angling the roadside surface by 30 degrees or more can deflect and disrupt(mute) sound upward and away from people.

[@nunya___]

@@Salattrainer That's bad engineering Germany. There is a great example of a wall that didn't fall without great effort...trying to remember where that was....

[@gheebuttersnaps2011]

Imagine if every highway was made into a tunnel with little cut outs for the exits. No outside noise, no weather, lights could make it day time 24 7, no deer, no plowing/salting. I know I'm gonna have everyone telling how stupid I am and how it would never work but I just think it's a cool idea.

[@Ascertivus]

I think it’s a cool idea, too! It would be expensive, labor-intensive, and put the occupants of the tunnel at greater risk of fire, but the benefits for those on and above the ground would be great! Valuable land could be used for things other than large, noisy roads, neighborhoods and communities wouldn’t have to be split up, and the arguable eyesore of highways would be gone!

[@andyc9902]

Just add Stryofoam on the walls

[@allissaho9261]

In Hong Kong, the government put a tube over the highway... blocks rain and it stops the noise.

[@overlisted]

just don't build houses around big roads lolololol

[@mohammedsarker5756]

or build less highways and more mass transit

[@adambennett805]

Problem is those houses were built before the roads or traffic

[@overlisted]

@@mohammedsarker5756 that won't happen in america

[@zoanth4]

Most houses around major roads and highways were there long before. Immenent domain and all that

[@zoanth4]

@@mohammedsarker5756 we don't want that in america. Only the rich snobby urban liberals want it because living in stuffy metro areas without a car is their choice.. We prefer our freedom of movement in our vast nation as a collective. You'll be hard pressed to find any middle class people in america that prefer the restrictions of public transportation over cars. We also prefer lower tax rates. We hate even our best public transportation systems. The mta here in NYC is corrupt, expensive, dangerous, and always late. -nyc guy who's lived all over the country

[@kevinorghidan4384]

I always saw those when driving on the highway, but I was thinking that this is for the light from the car to not reach at people houses at night. I learn a new thing today thanks to YT

[@strawberryjam3670]

In germany, we either have them in a special diffused shape, or we use dirt mounds overgrown with grass and local plants.

[@richinoregon]

The atmospheric condition which defeats sound barriers is called an inversion, where the temperature rises with height-cool clear nights are ideal for inversions. I live about a mile from the freeway and generally can't hear the noise, but when there is an inversion I can hear the highway noise very clearly. In fact, I can hear trains five miles away easily.

[@VinceTheCreatorr]

Engineers of these sound barriers finessed the city to build shitty concrete walls instead of just using trees.

[@GarretGrayCamera]

We live in such a noisy world that it's no wonder people go crazy. There's a story out of Australia where they built a pedestrian bridge over a highway. Not only do the neighbors deal with the highway sound but the way the pedestrian bridge is constructed, it resonates and produces a high pitched hum when it's windy out. And the same thing is happening with the Golden Gate Bridge after a renovation.

[@jabber1990]

imagine living next to a highway and then complaining about the noise

[@brandonaynesmay352]

Well you live where you live. I ask why anyone would live right next to the road or on a corner turn. Just so you get lights flashed at your house or possibly get hit by a car.

[@paulsehstedt6275]

The barriers must be curved on the upper quarter or lean in the direction of the noise source to reflect the road noise back to the traffic. Wooden crash barriers are also helpful for noise reduction.

[@aidanpeairs1967]

My town has no interstates in it and it’s a blessing even with dealing with traffic lights