The massive Fatigue Carousel helps keep roads safe

The "accelerated pavement testing facility" in Nantes can simulate decades of road traffic in a few months. Here's how. ■ More information: lames.univ-gustave-eiffel.fr/...
Editor: Dave Stevenson davestevenson.co.uk
Camera: Guillaume Juin www.guillaumejuin.fr
Producer: Axel Zeiliger at Block8 block8production.com
Thanks to Jérémie Chabot for the suggestion
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[@TomScottGo]

I really hope the scale of this comes across on camera. Drone shots would have been wonderful, but unfortunately the Carousel is just a couple of kilometres away from an airport!

[@dankweedo]

I was feeling a little uneasy for you just watching the video so the scale of it definitely came across

[@quad7685]

One day you're literally just going to go to the I.S.S.

[@ThePrikoki]

imagine how people in the planes must look at this having no clue what it is :)

[@Taxxi88]

How do you always come up with these original video topics?

[@shawnhartmann4581]

I am conflicted. It is a good rule to maintain a distance between drone use and airports. On the other hand, I am emotionally and philosophically pre-disposed to believe that nothing should stand in the way of knowledge and dissemination of information.

[@Voltaic_Fire]

"A fatigue carousel" is a great way of describing a really exhausting week and that's exactly what I'm going to start calling it.

[@kellyalvarado6533]

I think that's just called "a job" by most people. 😄😁

[@RFC-3514]

As opposed to carousel fatigue, which is what carnies get.

[@nayhem]

The Weary-Go-Round

[@NoVIcE_Source]

@@kellyalvarado6533 well that's discouraging

[@WhoThisMonkey]

A carnival of fuckery. ^ employment.

[@zukaro]

The fatigue carousel is what I'm calling my internship from now on.

[@IstasPumaNevada]

This is funny and painful all at once.

[@maxsnts]

Chances are you will be calling that to the future job to. Liking a job is not as common as people think and even the ones we do tend to wear-off after a while.

[@csn583]

Massive fatigue carousel that spins terrifyingly fast: a memoir.

[@csn583]

Or just a subtitle for Planet Earth.

[@ToriKo_]

LMAO

[@synjdcrispy7843]

This covers something I deal with at work ALL the time. Management is always looking to do things more cost effectively, which makes complete sense, but they are convinced that everything can be analyzed on computers, eliminating the need to expensive real world tests. They actually asked the engineers "what additional modeling and simulation tools/packages do you need to eliminate testing?" It's mind melting trying to explain things to them when they have tunnel-vision on eliminating a large budget item. No matter how sophisticated and detailed your models are, there are always assumptions that need to be made in building them. You need that physical data to actually show the models are giving the correct results, and if not, make fixes/corrections/adjustments to the models to have them line up. You do this up front, the models can save tons of money and time down the line.

[@isekaijoucho4812]

they just want to make money, we (engineer, dev) wanna make it works well and long lasting

[@JD-ub5ic]

Wait until they have some expensive real world rework that occurs because they didn't build a prototype, then for the next 5 years or so it'll be all "test everything simulations aren't enough" until the memory of that fades and they go back to "simulate everything we don't need prototypes" repeat ad infimum. Where I work we call these revolving management/corporate pushes the "flavor of the month" 😅

[@moteroargentino7944]

Yes, models were never meant to eliminate real testing, just reduce it.

[@glenthemann]

That didn't matter through the pandemic at all. It's the way it is. Trust the models, trust the science bro.

[@0783155]

I always say to my boss in this situation: Who is testing the automated tests? Who validates their results are what it is in real life use cases?

[@drb0mb]

I'm glad you addressed the fact that weather and temperature cycles are absent from this testing, because it's a glaringly significant contributor to road wear. People who don't live in a place that experiences all four seasons don't know the misery of potholes in spring followed by repair in summer.

[@george5156]

Sure they do if they have Chinese pavement

[@joansparky4439]

North Queensland (all of North AUS) only has got two seasons (wet and dry) but we also get lots of potholes.. they appear in the wet, when the underground gets soaked and imperfections in the road-base (little bit softer than elsewhere) leads to deformation, cracks, water ingress and lo and behold.. when it's raining for a couple days you easily get potholes that will kill a cars suspension in one go.

[@Ali-mv3jc]

@@george5156 what is Chinese pavement?

[@jfruser]

@@Ali-mv3jc A mix of ground-up hopes, dreams, and bones of falun gong practitioners.

[@carlsaganlives5112]

@@Ali-mv3jc Brick.

[@pup64hcp]

Tom Scott: always pointing out things I didn't know existed but now that I think of them they make perfect sense

[@MawDaws]

the j

[@riley6034]

True

[@ArchaeopteryxStudios]

You are right. I never thought that there was a Frenchman who really spoke English.

[@tycarne7850]

@@ArchaeopteryxStudios Many Frenchmen can speak excellent English. They just don't want to speak to the English.

[@itskdog]

That's why it's called "Things you might not know" :P

[@GrahamRead101]

One of the mysteries in life - how does Tom Scott find all these niche things that you never knew about - but sort of make sense when you hear about them!

[@ariovistus1491]

They just show up in his inbox

[@soundscape26]

Great research and a big number of handy suggestions and invitations.

[@418_im_a_teapot]

depths of wikipedia may I suggest

[@thoatran2718]

ok

[@DenkyManner]

@@James_489 A shame some guy with a chip on his shoulder can come along and make baseless claims.

[@cansabanci]

4:37 - as an aerospace engineer I totally agree with that. there are aerodynamics analysis tools called CFD - computational fluid dynamics. but my professors used to call them colorful fluid dynamics (bc they give you nice colorful contour images as results :D). because the chaos theory applies to fluid dynamics, minor changes in the initial conditions can cause massive differences. therefore you can only trust them *a little* after you validate its results with real test data by changing some parameters in the tool.

[@tatraurbex]

An aerospace engineer who worked at Boeing and brought himself in Enumclaw Washington state and got himself f*cked to death by a stallion? (Mr Hands) I'm sorry, but when I saw aerospace engineer I thought of this

[@halogeek6]

This dude talking about his machine in a succinct way with pride is just wholesome and informative.

[@spoopypoods7485]

1:21 “Suspension compression” and “Thermoplongeurs” are exactly the kind of buttons I expect to find in a fatigue carousel

[@AdamJRichardson]

"Oui" @1:23

[@namename8004]

Lubrification

[@Dood_]

It's not compression, it's compressor. You can see the axles on the machine have a regular air bag suspension from a truck and these need compressed air.

[@BossCoins2]

Also “lubrification” and “marche”

[@namename8004]

@Dood Uhm ackchually it's "compresseurs suspensions".

[@AnimeFan-wd5pq]

I love stress tests that actually use these cool practical tests instead of some math along with tiny test samples. There’s a reason for both, but seeing the test in action is just a lot more fun.

[@Kat21]

Yes very interesting

[@jackmclane1826]

Watching fatique tests can be the most mind numbingly boring thing on this planet. I had to do a bit of it..

[@SimonZerafa]

Could they test tyre wear using this rig as well as road construction? 🙂

[@CoconutMigrating]

@@SimonZerafa tire wear is already tested. That’s one of the ratings on your sidewall.

[@darrennew8211]

Sort of like watching the machine that tests the buttons or hinges on an old flip-phone, opening and closing the thing 20,000 times with something that looks creepily like a human hand.

[@Nalehw]

I hope Tom remembers to gets his cameras back when the testing finishes in a few months.

[@baryonyxwalkeri3957]

I do wonder, how many wheels / tires does this facility go through during a testing cycle?

[@rauknrolf]

This was exactly what crossed my mind too. The wear and tear of those tires must mean that they need to be changed very often?

[@Fromatic]

Would be interesting to know, I would guess 1 as even though its constantly turning slightly theres no load applied through the turn like a real vehicle where the turn is caused by the friction of the tires physically changing the direction of the vehicle, and acceleration and braking which would also increase wear are again not being applied through the wheels, all they're really doing is simulating the weight of a vehicle but the tyres arent really having the same forces put through them as they would on an actual vehicle

[@railnut8453]

I wonder if the tire manufacturers use this to test their tires too!!??

[@HappyBeezerStudios]

@@railnut8453 Maybe they can cut a deal. modified road surface with standard tyres and modified tyres with standard road surfaces.

[@thomasbennett3349]

Bet they'll last longer than ours, so we change whilst there's still tread, could run these to slicks few k more miles there

[@lightermicrobe8521]

That carousel is ablsoulty terrifying, I'm going to have vaguely infrastructure-themed dreams for weeks, Thanks Tom! 10/10 would show to friends and family :)

[@bontrom8]

This is the stuff of video games! Reminiscent of the ridiculously huge machinery of Unreal or Halo.

[@endroo93]

While Rammstein's Benzin is playing in an endless loop.

[@taylorh.3484]

I want to ride this thing while I listen to Rammstein on my phone!

[@Sukadia]

*nightmares, for sure

[@bamb8s436]

@@taylorh.3484 Du. Du hast. Du hast mich. Du hast mich gefragt

[@Magmafrost13]

I want not prepared for how utterly terrifying this machine is, even through a video. I think the scale really does come across on camera here (I imagine that shot of how much it squashed the wheel at the start of the video really helped sell the weight of it), its scary just to watch, I cant imagine standing next to it

[@railgap]

13 RPM. O_O I mean... YIKES. If the tires can run up to 100km/hr, no wonder the ends of the arms need aerocovers!

[@SeanBZA]

Yes, consider that to get those wheels to compress that much you need 130 tons plus of load on them, more than double the normal mass of a fully loaded truck tractor and trailer combination, that will be spread out over 5 axles as well, and 18 tyres.

[@kennorcott7074]

As someone who works on and operates large theme park rides, it’s exactly as terrifying as you think. The scariest ride I’ve ever worked on is similar to this, but with people on the ends of the arms, and us operators have to stand within 5 feet of where it spins. It’s terrifying

[@Undy1]

I would love to see this recorded for VR - that's certainly a sure way to make the size translate perfectly to the viewer.

[@KevinSantifort]

Actually anxiety inducing

[@specterx2135]

This guy can make testing pavement interesting. That’s how you know he’s done a good job at this

[@pacificostudios]

When I worked for Minnesota Dept. of Transportation, the Research Dept. was proud of establishing a test site on a real piece of freeway with real traffic. This machine gets data a lot faster than that.

[@FurnitureFan]

Right, the fatigue carousel must save a great deal of public money by identifying the most durable materials beforehand.

[@KappaKiller108]

@@FurnitureFan in the long term for a large area maybe, but I imagine this machine cost millions of dollars to design build and operate

[@user-tr2dh4xx6u]

@@KappaKiller108 hardly a million... its a simple machine that rotates and it has a few sensors only... operation is just the price of electricity which is cheaper than gas and the staff plus a bit of maintenance. do you have any idea how much money goes into just the raw materials of a road without even counting the labor, planning and cost of the land rights?

[@Sam-tb9xu]

Except the Minnesota machine actually tests freeze thaw cycles and this machine does not.

[@Cookiedible]

@@KappaKiller108 as he said, this specific one is 40 years old already. It's had time to make billions of return on investment.

[@oscargill423]

Two fascinating things I learned from this video: 1. There are things called fatigue carousels responsible for testing roads 2. There are windproof mics

[@zionm.]

They have a dead cat on them

[@shahan484]

@@zionm. Mink fur

[@kimngo1629]

ok

[@gauravjha8938]

Alice in Wonderland..

[@lilkurd2000]

Also you can see how much something weights by simply looking at a tire(even with out knowing how much air it is in it)

[@keystone5750]

Wipeout in shambles rn

[@windowsxpmemesandstufflol]

Ok I don’t think that’s good idea to put in wipeout though.

[@ashiwashi]

lmao

[@caratomlinson3552]

@@windowsxpmemesandstufflol oh shut up u ming

[@caratomlinson3552]

@@windowsxpmemesandstufflol Shush u mong

[@3ekaust]

Now that would litterally wipe out the contestants

[@magicalcapi9148]

"this spins terrifyingly fast" *says while posing with a smile and a thumbs up in front of the deadly machine* yup, that's our Tom

[@fido_7]

I actually live in Nantes and didn't know this carousel existed. It's great to learn something new !

[@BrooksMoses]

For those wondering about tire life: At the typical speed of 70km/h, that's about 1700km in a day, or 50,000km in a month. Commercial truck tires are apparently expected to last somewhere between that long and twice that long, spending on which hastily-found online source one reads.

[@EdwardMillen]

I was just wondering exactly that, thanks. The other thing I was wondering is what those speeds etc are in mph, so I'll add some conversions here for anyone else: 70km/h: 43.5mph 100km/h: 62.1mph 1700km: 1056 miles 50,000km: 31,068 miles

[@ehcanadiankid1]

also the biggest ware and tear on tires is accelerating and decelerating maintaining a consistent speed will add much life

[@sharx892]

I wonder how many blowouts they had over the years. This could be a test on tires for lunatics in roundabouts. xD

[@ke6gwf]

@@ehcanadiankid1 actually the biggest wear and tear on truck tires is curves, because it is scrubbing the inner and outer edges at different speeds, and I noticed some cupping on these, probably because it's constantly going around a curve.

[@tissuepaper9962]

@@ke6gwf the tires aren't being subjected to lateral gs. The centripetal force is provided by the arms of the centrifuge, not the tires. These tires are being loaded as if they were going mostly straight.

[@marcianoacuerda]

The limitations Mr Hornych talks at the end are just as important as the benefits. I really enjoy listening to researchers because they try to look at every angle possible.

[@pattheplanter]

I wonder if there are materials that are fine on curves but fail rapidly on the straight.

[@AugmentedSmurf]

@@pattheplanter I imagine that ruts and grooves appear more in straights than on curves. I can't imagine that a lot of people will take the same exact route through a curve, but when it comes to straights, people will generally just follow the middle of the lane.

[@MonkeyJedi99]

@@pattheplanter Hmm... Something with good shear profile, but bad compression response?

[@Glaggle]

@@pattheplanter In this case I don't think it matters. The road surface should not experience any transverse force from the wheels because the centripetal force is on the rotor.

[@ringandpinion3064]

Hats off to the engineer, his presentation was very informative.

[@mattflamand3734]

This was a really cool video. You always do such a good job putting these together. Cheers

[@hallamhal]

I got three on my Tom Scott bingo today: "It's unnerving to be standing this close" "X doesn't just mean X, it can take months..." "I hope the size and scale is coming across on camera"

[@kingseekerbackup3085]

Bingo!

[@scp-049]

Where do I get a copy of the bingo card?

[@kelaarin]

Now make it a drinking game.

[@risingstar1309]

Don’t forget the “ah! I got x’d, ow”

[@bazza945]

Technical commentary on a porn video???!

[@theslowmoguys]

Utterly terrifying

[@cameronduff9820]

Hi Gav and/or Dan!

[@automanic595]

Only 10 likes as of right now 👀 Also, salutations Dan or Gav!

[@badasstank2969]

27 likes...

[@djmrhill]

I don't think this would be very interesting in Slow Mo

[@javidmirza4584]

Floopin

[@louiemcewan4911]

Thanks again Tom Scott! Again something I never new existed, and yet is quite fascinating. I really appreciate these videos

[@MuhChicken]

Absolutely fascinating! I really loved how knowledgeable that engineer was about the subject. That kind of professionalism makes me happy.

[@macsandsquid528]

Yet another job nobody told me about during the high school job fair, along with flinging chickens at airplanes. Thanks Tom.

[@56Gumball]

Not sure what, or if they fire anything at aeroplanes, but in the U.K. ducks (specially bred and humanely euthanised) of various weights and sizes are used for testing jet engines. 👍🏼

[@ol_smokey9370]

@@56Gumball They use chickens here in the states to test a variety of aircraft structures, including engines.

[@krashd]

@@56Gumball If they are humanely euthanised does that mean they survive their trip through the turbine?

[@jonnyblade3234]

Gentleman, thaw your chickens

[@MonkeyJedi99]

@@56Gumball I now have in my head the phrase, "A standard spherical duck."

[@man_on_wheelz]

I actually was just wondering about how civil engineers/scientists know what kind of abuse a road can take and how to measure lifespan of a road. Tom... always answering questions I never thought I'd get an answer to.

[@termitreter6545]

A lot of it is also just decades or centuries of experience. As the guy said, you cant speed up things like the asphalt deteriorating over time.

[@psychotropnilachtan8869]

Psychotropni Lachtan před 1 sekundou They take a wild guess. Most of these companies get liquidated after a while just so nobody can hold them accountable when it starts falling apart. And politicians are more than happy to secure new contracts for their buddies in construction bussiness so its not a big deal. Everyone wins, except the tax payers ofcourse.

[@MCshadr217]

Haven't figured that out in New Zealand yet, we use trucks going half the speed limit that will be set instead which does absolutely nothing (though our new road lasted about 2-3 months longer then expected recently, large step!)

[@mikeymasi]

california bearing ratios, relative densities, ESAs, drainage

[@thedeepesthat4029]

Mostly, there are set designs and specifications for road construction. There are many factors however that will effect the lifespan including the substrate that the road is built on etc. However the apparatus shown in this video will mostly be used for novel designs of road surface construction, for future development.

[@ulalaFrugilega]

"That’s a good sound."… of course Tom Scott is one to notice things like that. Love and Respect from Amsterdam!

[@alext1277]

I’m grateful I found one of your videos on my recommendation. It was the roller coaster one due to the fact that I went to an amusement park. Now I just watch all these interesting videos because I love learning all these things that I never know existed. The world is really fascinating. 🙏🏽

[@ashley_neal]

Driving is my profession and I didn't have a clue about these machines. Mind blown as normal Tom 👊

[@froggiee104]

Wasnt expecting to see you here! :)

[@horsesinmycar7179]

Your videos are amazing. I passed my driving test last Thursday 😃

[@austinbevis4266]

You seriously didn’t know?

[@davidandrew7314]

@@austinbevis4266 Are you acting like you did?

[@ozhinz]

@@davidandrew7314 💀💀💀

[@barnabas4608]

THE SHOT WHERE TOM HAS HIS BACK TO THE BEAST IS INSANE

[@TheRealBozz]

Never even imagined this. Never even entered my mind in any fashion. Unreal.

[@joshuawatson1902]

This is what I would call a perfect Tom Scott video. A really unique thing that does one job, and does it very well, that I didn’t know I wanted to learn about. Thank you!

[@clray123]

It's not a perfect Tom Scott video without Tom Scott strapping himself to the carousel and passing out due to G forces.

[@Zyo117]

Nah, that's Tom Scott Plus

[@iabervon]

This is such a Tom Scott subject that I thought I'd already seen a Tom Scott video about it until I realized that wherever I'd seen it previously didn't have in-person video with the person explaining it.

[@balaclava351]

Can we take a moment to appreciate how well this guy was able to communicate this in a second language. Amazing.

[@soundscape26]

Heavy accent but perfect grammar on a technical subject.

[@dereknalley]

That's because a TON of European people are fluent in at least two languages. Accented, yes, but functionally fluent. USA is the outlier.

[@gnarthdarkanen7464]

@@dereknalley Worth pointing out (regardless of what you might read) that the USA is easily the size of Europe, and ONE SINGLE NATION... While technically speaking, English isn't the National Language, things have simply provided that 90% or more of everyone in the U.S. speaks it best. Most of us have been through some training regarding at least one other language, and while it might help my getting around to brush up and keep fluency in my French, Spanish, Italian, German, and Latin... It's really not necessary. It makes it damnhably difficult to justify the expense... AND like any other skills, if you don't bother keeping it up, it deteriorates over time... I haven't actually found use in a single one of them in more than 20 years, so... I'm going to be rusty, and it's just not worth the travel over a couple THOUSAND MILES of ocean to find a territory where it would be worth the effort... NOT trying to argue or beat you down. Just pointing out the "technical details" as to WHY the USA is the "outlier". ;o)

[@joris914]

I've noticed this pattern of near perfect grammar and technical vocabulary, despite a strong native accent, often with academics. Particularly the older ones. Makes sense if you think about it, even in France a lot of the scientific community is international to the point where the main language is English.

[@australiananarchist480]

@@joris914 thanks to a little known group of people called The British Empire, and upon its downfall, the American Empire, English has become the lingua franca of the world. If you need to speak to a Syrian, a German, a Russian, a Spaniard and a Japanese person, why would you all learn eachothers language or bring translators for all of them, when you can just each learn english (which some of them probably know anyway) and youre good

[@petebeatminister]

A amazing machine, I never heard of that before. Thanks for showing.

[@snowfelon]

Wow this is incredible... I've never given much thought as to how materials are tested for durability. Fascinating! And that thing is really intimidating 😂

[@ToyKeeper]

That is seriously unnerving. I've had nightmares about being stuck to the outer wall of a machine like this, with incomprehensibly massive arms passing at astronomical speeds just inches from my face. I didn't know such a thing actually existed!

[@MonkeyJedi99]

You have a very scary and very specific nightmare.

[@hendrikdependrik1891]

Why are you so scared of an oversized helicopter rotor?

[@ToyKeeper]

@@MonkeyJedi99 It's not really a nightmare... that was just the easiest way to explain it in a single sentence. It's more like sort of a hallucination which happens while half-asleep or sometimes kinda while working. Like, have you ever felt like the bed was tilting or spinning? It's kind of like that, except it feels like laying on the inside of a ringworld looking toward the center, while planet-sized masses zoom by so close that they'd hit me if I tried to lay on my side. It's one of several weird hallucination-like things I get sometimes. It's not scary, but it is at least disorienting, and if it happens while awake I make sure not to do anything which requires a sense of balance.

[@BeeJay120]

I believe they have a machine like this at NASA to simulate g-force on astronauts

[@patheddles4004]

@@hendrikdependrik1891 Are you not scared of a regular-sized helicopter rotor? You should be.

[@NorthernPyro]

It looks like a giant terrifying fairground ride. I almost expect the arms to start bouncing up and down

[@leociresi4292]

It’s like they took the blades of a wind turbine and turned it into a thrill ride!

[@jonlawrence6338]

Thrill rides alone are quite the engineering marvel

[@PYROWORKSTV]

Just add some speed bumps to the test road!

[@Mimikkyudayo]

Imagine standing in the middle piece "Weee this is kind of fun, wait it's getting faster, uhh its not stopping, TURN IT OFF PLEASE I CAN'T HOLD ON MUCH LONGER"

[@bobhilbig7704]

Makes me so happy to see tom travelling the world again. Means the world is getting slowly back to normal.

[@RogerOThornhill]

You finally broke me! A video so dry even I couldn't get through it. Cudos:)

[@RestoreIt]

How do you find these places, Tom? Great video, cheers!

[@Toykio]

Suggestions of viewers, PR invites from companies or research by his production team at Block8. This time it was a suggestion which is mentioned in the video description.

[@rafaelskt4ever]

These places find Tom

[@ilyapopov823]

"I've got an email..."

[@ayisdec716]

legit

[@xxclusive8380]

@@rafaelskt4ever yep

[@cynnicysm]

Much respect to the small inner ring of apparently indestructible material, quietly holding up without being part of the test.

[@patheddles4004]

Solid thick concrete will do that, if you put practically no load on it.

[@tissuepaper9962]

Most of the load is on the outer wheels, mind.

[@ironfront9573]

Is it driven from the centre or each arm?

[@patheddles4004]

@@ironfront9573 it's driven from the centre - that's where the 1000HP electric motor is

[@benhobby17]

@@patheddles4004 hydraulic motor according to the video

[@HakarDoski]

large machines have always been frightening for me, and seeing them move at drastic speeds is absolutely terrifying.

[@thecursed01]

then since it's still close to halloween, look up pictures of ppl standing in front of/next to an aircraft carrier...then read how fast they can go translated to mph/kmh

[@barefootalien]

Neat! I had no idea this existed! Thanks for sharing it!

[@CreedBrattonTheOffice]

As an FWD (Falling Weight Deflectometer) operator I never knew these existed. My job is to do the same as this but on a smaller scale (using an FWD) on already built or under construction roads as part of QA checks but never thought about what they might use when coming up with new road designs to test. Thanks Tom for the cool video.

[@j.wa.1061]

now I'm really curious what that looks like. How do you do QA tests on already built roads? When do you do QA checks on roads?

[@CreedBrattonTheOffice]

@@j.wa.1061 You can lookup FWD's on google to see what they look like. There are different types but generally a trailer with lead weights in the middle (like those stacked weights with the pin you see at the gym but much heavier). Usually 9 or 10 geophones positioned along some sort of boom. The machine lowers to the ground where you position it and the weights hit the part on the ground (the foot) and you get a deflection into the pavement that the geophone sensors pick up. Based on what values you get from those you can determine quality of the road structure and even how long you expect it to last, especially if you have info like layer type/materials and traffic counts. Usually you just plop along the road doing a test every x distance with some sort of traffic management behind. That's the basic of it.

[@j.wa.1061]

@@CreedBrattonTheOffice cool! I don't think I've ever seen one in my neck of the woods, but now I'll know what it is if I do. :)

[@vigilantcosmicpenguin8721]

A falling weight deflectometer operator? I thought you were in quabity assuance.

[@saurabhponkshe]

I thought you worked at a dog food company in quabity assuming

[@bootsowen]

Hi Tom, I am so glad that you have shown this because pavement engineering is one of those niche areas that only a few people know about. In the UK we had a similar machine, the Pavement Test Facility at the Transport Research Laboratory (TRL) at Crowthorne in Berkshire, But it was retired due to lack of work a few years ago.

[@blueredbrick]

Surely the one in the UK spun the other way? 😎

[@PatrickBergersen]

@@blueredbrick hahaha

[@omardude39]

But why? Most of the pavements I've walked on over the boarder in Buckinghamshire are dire, if anyone should be testing new surfaces it's us English

[@fgaze72]

@@omardude39 You should come up to Scotland mate, it's even worse

[@tim_1_]

@@fgaze72 so true. although rather than the materials of the roads, I think it is more that the roads are cut to shreds by utility companies that repair them terribly (at least in Edinburgh it seems this way)

[@oxstorm644]

appreciate the short video format. interesting and to the point

[@George11lee]

How do you find these amazing things. Its truly awesome and makes you wonder how much goes on behind the scenes of every day life. Thanks for the great video.

[@davidgannon5388]

At the Federal Aviation Administration's William J. Hughes Technical Center in New Jersey, there is a hangar where runway materials are tested. The most stress on a runway does not occur at landing. At landing, most of the fuel is gone, and the wings are still providing some lift. The real load happens during taxiing to the takeoff spot, when the plane is traveling too slowly for the wings to help at all. At that point, every ounce of the plane's weight, passengers, crew, baggage, and fuel are bearing down on the macadam. So, in that hangar, there is a gigantic gantry that rides along two rails on opposing sides, running the length of the building. Between the rails is the runway material being tested. It is built atop dirt, and exactly as a real runway. From the gantry is a large machine with hydraulics and wheels configured as those of a jetliner. Depending on the test, they can set the tires and the setup for literally any passenger or cargo aircraft in the world, at any weight level. The test consists of the gantry slowly moving (at taxi speed) along the length of the hangar to the runway's end, then stops and reverses to the other end. Back and forth for weeks or months until the runway fails. Then they analyze where and how it failed, rip up the runway, and lay a new one down. It takes a long time, but the data is wholly worth it!

[@andyandreou]

Wow, you'd think runway paving techniques were a done deal, but they keep being improved. New materials?

[@halfgecko3202]

@@andyandreou or new aircraft

[@MonkeyJedi99]

@@halfgecko3202 Good point. As engines and aerodynamics improve, they combine with economic pressures to result in bigger and bigger planes, both passenger and the cargo monsters.

[@cjmillsnun]

Have to disagree here, taxiways last compared to the runways. Surely the point of rotation would be where the worst loads are. the front comes up and for a second or so, the main gear is pushed into the ground until the wings are at the right angle to generate lift.

[@patheddles4004]

@@cjmillsnun Nah, rotation happens when the wings are already generating enough lift to counteract the gross weight of the plane. At that point the load on the runway surface is tiny.

[@QualityDoggo]

the fact the wheels each have what looks like a wing over it really shows how fast it's designed to go if the air resistance is so significant

[@mike140298]

I'd guess it isn't as much to allow it to go to high speeds. But more to prevent the air to go around it in such a way that makes it vibrate. Vibrations can cause a lot of wear and tear, and this machine needs a lot of up time, and little down time.

[@DidierLoiseau]

Isn't it used to properly control the simulated weight, by slightly inclining them?

[@krashd]

@@DidierLoiseau That would make sense, if you alter the angle of attack you could create more up or down force on the fly without having to physically add or remove weight. Fantastic design choice.

[@JeffreyJakucyk]

I wish Tom explained what they were for.

[@wincentwaxin1432]

On 4:37 i love how Tom moves his hands with the machine

[@naniruja3407]

I read about this for my bachelor's degree thesis on dynamic analysis of pavement... at the time I really needed some real life data from the test for FEA modeling of pavement cross sections. Am glad I came across this video... brings back memories. Btw I'm from India and it was all far from reach then, and still is from what I believe.

[@shinyagumon7015]

Imagine what the process of coming up with this must have been like. Like someone says: "We need to test new road pavement for long term fatigue, how can we do that without inventing a time machine? Any ideas?" And then a group of engineers did a brainstorming session and their answer was *Giant circular vehicle that can run so fast that it simulates years of damage in a few months.* Ingenious

[@madmanwithaplan1826]

I don't think it's simulating years of wear just months from which they can extrapolate how damaged it likely be over the years.

[@tsm688]

@@madmanwithaplan1826 the thing is they can run it very hard and continuously. Fully loaded, bumper-to-bumper weight like a traffic jam, but screaming along at 70km/h. That's conditions harder than the real world

[@philipphermann9454]

@@madmanwithaplan1826 I'm not so sure about that. Usually road surfaces are layed out for a certain number of 10-t-equivalent axle transitions in 30 years - and this machine can test the number very precisely - just take the number of rotations and multiply by 4. At least for surfaces that don't face that much heavy traffic (lets say 3.000.000 10-t-equivalent transitions, which is your usual road that connects two villages) this machine has to run only for less than two months. With the numbers given in the video (120 m length, 70 kph speed, 4 arms) the result is the following: N = 3.000.000 (10-t-eq. transitions) / 4 (arms) = 750.000 (rotations) T = l/v = 0,12 km / 70 km/h = 0,001714 h t = N * T = 1.285 h = 54 d = 7,65 weeks

[@monhi64]

I think it just simulates a lot of cars at once nonstop, they said it typically runs at 70 kph which is not particularly fast.

[@wojciechbieniek4029]

Another brilliant piece of engineering was a Michelin Citroen DS PLR, designed to test tyres!

[@aschoenecke]

Kansas State University has one of these in the Civil Engineering Department! It goes back and forth on the same track, and also includes the “wander” feature for real traffic. That one also has climate control because it’s indoors. It’s cool to see this French version which is bigger and smoother.

[@DonOblivious]

In Minnesota we test it with real use on a real freeway. We've got a stretch of freeway that they lay down the test material and have actual, varied, traffic drive over it through multiple seasons to see how the pavement blend holds up in real world conditions. The people doing the studies can divert traffic onto or off of the test track so they can repave the test track without interrupting traffic when they resurface the test track. That lets them see how the pavement handles through our legendarily bad freeze-thaw cycles.

[@aschoenecke]

@@DonOblivious That’s cool! Nice!

[@lasivianleandros3558]

Always so damned interesting Tom. Love it. :)

[@clemencethezebra9901]

Thanks! I live in France, I gotta go check that out for my next vacation

[@jacob_90s]

For anyone curious, the centripetal acceleration is right around 4.9g's with it moving at 100km/h

[@HuBrFe]

holy

[@emilysmith6897]

@@HuBrFe this is nothing for an industrial machine.

[@JNCressey]

5 grams aint so bad ... 🙃

[@skoniramont]

and now imagine some nutjobs who wanted to build that vertically, and fling objects into orbit,... in a vacuum,... where the seal brakes at launch,... with a sudden release of the weight on one side,... with the controlcenter right next to it,...

[@shirou9790]

Hmm for a ring length of 120 m (=circumference) and a speed of 100 km/h I found the acceleration to be 40.4 m/s², or around 4.1 g's (and at 70 km/h it drops to 2 g, which makes sense if centripetal acceleration is proportional to the speed squared, so that 70% of the speed means 49% of the acceleration)

[@EMAngel2718]

I really appreciate the way you can make a 5 minute video that feels like more than a lot of 10+ minute ones

[@ratkebab9536]

@Deto Qcney I bet $$$ is the only problem

[@newt2010]

Very cool. Had no idea this was done or even a thing. Thanks for the video

[@matoflynn]

The kind of journalism I love

[@Goat-on-a-Stick]

You have a knack for finding the most interesting stuff!

[@theom.605]

How tf u get verified as a goat on a stick

[@sangvoba4340]

ok

[@mikefowler6623]

I think Tom's special skill is taking otherwise mundane things and making them very interesting.

[@werttawertta]

500th like

[@clarkecorvo2692]

@@werttawertta pff.. 520. get on my level, kid.

[@davidwilliams5497]

Worst amusement park ride ever. They wouldn’t even let Tom sit on it. 0/10 would not ride again. J/K. I love seeing practical testing like this. Thanks for the insightful video.

[@Job.Well.Done_01]

🤣🤪

[@OntarioTrafficMan]

Accelerated Pavement Testing Rig 1 looks too intense for me

[@krissp8712]

You should see the rusty old one that injured Tom!

[@davidwilliams5497]

@@krissp8712 the self-powered one. classic. 10/10 would get stitches again.

[@DomenBremecXCVI]

Imagine they let you on but you can't go off of it for months

[@seandezart8294]

I have worked on several test materials here SW of Nantes. Beginning with the final 'earth' layer through several asphalt layers to the 'road' surface. Some very innovative processes have been tested ;-)

[@richard--s]

The size of the machine comes through, the sound, we see the wind it makes on your T-Shirt, we hear your description of your feelings, all this together with the visual impression gives a sense of how massive it is... Together with the description of the test load for each wheel, a few tons, 5 to 8 tons or so, that mass must sit in the structure on top of each wheel, there is no other way to do this... (That last thing was just the bare analysis part, but that adds to the impressions I mentioned before). Maybe I would have hidden behind the more or less massive fence ;-) And would have increased my distance even more and would casually look to hide behind a building or something ;-) So, yes, the scale of it comes through for me... Many thanks for this video idea and for this video... wow... It does not quite come through on the thumbnail though, but it's more than worth to watch this video! Many thanks for this video!

[@AceSkates]

I love how someone always has to think of a way to break something

[@holgerchristiansen4003]

Indeed. The question for infrastructure is never "Will it break?" but "How and when will it break?"

[@Autoskip]

@@holgerchristiansen4003 and “How can we make it break faster so that we can figure out the other answers?”

[@cheapcigs9772]

Everything ends, planning for the inevitable is just logical

[@tactileslut]

Acme Destructive Testing: you make it, we break it, guaranteed.

[@eswift8318]

Don't know why they need these big machines. Could just let a bunch of middle school kids in there for a few minutes.

[@pkbreeze08]

I love the community that you have built here Tom. The people that guide you to these places are true champions of learning and education and sharing lesser known experiences with the world. Thank you for another interesting video.

[@Ralph2]

Don't blame you for feeling uncomfortable standing there. I mean, I felt uncomfortable just watching the video! Thanks Tom for yet another informative video on something I didn't know existed.

[@franzkoviakalak6981]

This was utterly fascinating.

[@dbackscott]

As a civil geotechnical engineer, this is fascinating to me. I’d love to get ahold of their data.

[@elgatto3133]

A visit from a soil wizard. People think soil isn't so complex, but they would be very wrong.

[@Kevindeuxieme]

@@elgatto3133 Oh, spare us the usual geo-engineering soililoquy

[@SnowMexicann]

this was an entertaining interaction in this thread

[@Robbie06261995]

I always liked when road tripping I’d come across a sign stating “test pavement next X miles” but was always sad when there was no survey at the end.

[@rannnoch]

Yep. Tried to submit many test pavement results at the little phones they put at the side of the road but all it did was get me blacklisted from AAA services....

[@vigilantcosmicpenguin8721]

That would be fun if they had a survey at the end. Like, you drive into what looks like a toll booth, but it just prints out a form and you have to fill it in before you continue.

[@robertwoodliff2536]

I worked on the M62 on the matrix signalling system ..... the is one overhead gantry ( near Liverpool) that stretches the full width of the motorway ie all six lanes., you can feel the ' bounce ' as the HGV s go under it..All good fun.....when the rain is coming sideway at you on a cold Tuesday morning..

[@SentzOu]

Thanks for sharing the 'm gonna try it out later.

[@jasonbraun127]

Kind of puts into perspective how scary cars are. When I walk by a street I'm so used to seeing them drive past me at terrifying speeds (probably not 100 km/h but definitely close to deadly) that it doesn't phase me that much anymore but this thing puts that very rational fear of getting hit by fast metal husks back into my soul.

[@gogokowai]

A car moving at 10 km/h can kill you, so it's definitely deadly. It's definitely a daunting machine. It's similar to the feeling of standing near a highway. The speed limit on most highways here in the US is 70-75 mph(110-125 km/h), and driving at the speed limit is actually dangerous because most cars are going at least an extra 10-15 km/h faster, and the occasional drivers going 150 km/h.

[@kylegonewild]

We do just kinda tune things out sometimes. You snap back to reality though when a 70,000 pound tractor trailer roars by you doing 100mph and the wind cone hits you hard enough to knock you off your feet.

[@weetikissa]

Cars are deadly af. It's incredible how many deaths and injuries the car industry gets away with. Imagine if trains and planes killed as many people per mile traveled.

[@dsmyify]

See while out cycling sometimes I reach a max speed of 20mph and it's a rush. Go in a car and 20mph feels like a yawn.

[@andrewhazlewood4569]

Cars kill more people than guns in most parts of the world

[@wilsonguilger]

At work (agriculture tractor parts supplier) I've seen something very close to this, but instead the test subject is the moving part, not the floor. Tractors ate tied to the center and kept driving in circles through many obstacles as a way of validating its fatigue strength. It is so similar to this that now I'm wondering what else is running in circles out there.

[@george5156]

Surely the earth runs in circles

[@moistenvelopes]

Probably they use something like that to calibrate the arm on dump trucks that lifts bins

[@joansparky4439]

I've seen horses on a leash directed in circles over obstacles.. also fatigue testing? 🤔

[@darren25061965]

The Houses of Parliament run in circles, or at least the occupants do, constantly.

[@fredboat]

Very interesting, I had never heard of this machine. Thanks from Texas,usa.

[@AtomicShrimp]

3:35 that hexagonal tiled surface isn't 'Solar Freakin Roadways' is it?

[@insert_username_here]

Wouldn't last a week with the carousel.

[@ReprobateMind]

Nah, that only existed in the head of a scammer and the PC of an animator.

[@alexhajnal107]

@@insert_username_here I'd be surprised if it lasted an hour

[@phodder]

Or conductive charging plates? 🤔

[@jhonbus]

@@alexhajnal107 I'd genuinely be shocked if it lasted one complete revolution!

[@redonsundays]

I always imagined something like this had to exist, I just never researched or confirmed it. Thanks for the video

[@olik136]

there is only one problem (at least in Germany)- when the local government is searching for contractors to do the actual work, they have to use the cheapest one... and they do not consider long term costs... that is why our streets are mostly made from bitumen and not from concrete... although concrete lasts at least 3x as long, is more silent and so on.... but the initial cost is like 30% higher... so it almost never gets used..

[@IstasPumaNevada]

@@olik136 Concrete roads where I live are noticeably louder than bitumen, both for the travelers and the people near the road. I really don't like when I come across stretches of concrete highway on long road trips, the extra noise is irritating and mentally fatiguing.

[@Jehty21]

@@olik136 so you never visited east Germany? Because if you had you wouldn't advertise for concrete roads. And that they don't consider long term costs is also wrong. Long term costs is one part of the cost-calculation.

[@Zyo117]

Concrete roads when laid need weeks to dry and cure before they can be driven on again. It's not really viable for most places to shut down significant stretches of road for a long period of time for modifications like that.

[@squirlmy]

@@Jehty21 I don't know what problems east (East?) Germany has, but Canada has long stretches of concrete highways that are great, of course there is little choice, frost heaves would destroy bitumen every winter, maybe more than once within a single winter season. Also, I mean, it wouldn't be the only good idea that got totally f'k'd in execution in Eastern Europe.

[@sisterjudith3994]

I’m not working today so I’m going to chill out with a cuppa and binge Tom Scott starting with this one.

[@thundergunn]

I live near the Minnesota Road Research facility. General traffic gets to drive through a section that intersect Interstate Hwy 94.

[@emilyjanet455]

Here's my very Canadian question: How do we test how these new fancy pavements behave during freeze-thaw cycles? Forget vehicle traffic, that's the big destroyer of roads around here!

[@Bawbalicious]

A video from Not Just Bikes emphasized how much more traffic does than freeze thaw cycles, specifically in Canada too. So I'd research that claim!

[@RobinRense]

I suspect they test that in a big fridge 😅

[@jcxz983]

@@RobinRense Yes, very big, they call it Canada. :P

[@prylosecorsomething3194]

@@Bawbalicious I haven't seen that video but I'm gonna assume it's heavily flawed. Traffic doesn't cause part of the road to just drop six inches randomly like frost does

[@FrostyNut]

Probably same way pavements tested elsewhere..... We have a main road (80km/h non-urban) that had approx 30-50m section that was used for pavement testing, and was signed posted as "Trail Pavement in Use".

[@Kircic]

babe wake up tom scott just uploaded

[@Kat21]

yes

[@artisanrox]

This is the coolest thing I never knew existed. And also smart considering the cost of infrastructure projects.

[@gmurph623]

I love how the researcher is calmly explaining everything and then it cuts back to Tom terrified of the gigantic metal robot arms rushing past him.

[@rockaway149]

That moment Tom mentioned a 1000hp engine is powering this beast made me realize that there are some hypercars out there that literally have double the amount of horsepower compared to this beast. Made me realize how far the technique has actually come and how ridiculously overpowered those hypercar engines actually are.

[@carmadme]

Do renember torque though those cars won't have the torque of this

[@jimday666]

This has torque

[@matthewbeasley7765]

The duty cycle is a completely different thing though. This machine will do 1000HP for months at a time and last decades. At 1000HP any car engine won't last long if it sits at 100% for any length of time.

[@netoxicky]

Thats not exctly how it works though :D

[@insertchannelnamehere8685]

The other thing is a car needs good acceleration, this doesn't, it's allowed to take several minutes to get up to speed, so it really only needs enough HP to maintain 100kph, but not more than that.

[@felixs2654]

I would love to see some of the bogus solar roadway projects tested there. That would be slaughter. And maybe some improvements would result from the test data.

[@freedomofmotion]

On one of the other testing circles there was a section of hexagon plates that could well be glass 😂

[@Carrera075]

It looks like they were being tested there, at 3:35, the hexagonal shapes there look like the actual models of solar roadways, although they could be filled in with asphalt, so perhaps they were removed earlier.

[@felixs2654]

Ah. I missed that. Might also just be hexagonal slabs of some kind, but they look a lot like solar roadways.

[@macforme]

They can help pay for the facility by charging tire companies to test their tires on this machine. Thanks,Tom, for bring us info on stuff we didn't know existed but is always fascinating.

[@jamespink4202]

Awesome giant tech. Thanks Tom!

[@tasty_fish]

Tom: “Roads need to last decades French highways agency: “les routes doivent durer des siècles!” UK highways agency: “Roads need to last 5 minutes”

[@FurnitureFan]

😅 In fairness, UK roads have speed limits, which must slow down the deterioration process a bit.

[@BMC2]

Belgium: "you guys maintain roads?"

[@mecha-sheep7674]

Well, they don't last centuries. Those are not roman roads. Some roads are remade every few years (highway and heavy duty roads). Cars are not a problem, but as soon as you have heavy trucks on a regular basis, roads end up damaged very, very fast. This cost a lot of money, and is one of the reason I hate those trucks and loves trains.

[@zazak972]

And there is Quebec....

[@SirBojo4]

Montreal in a permanent state of maintenance

[@edwardlees4585]

I used to teach English to their colleagues just down the road in Angers where they did pre-studies on the asphalt materials to be used in the Nantes tests. A really interesting subject. Tom, while you were there did you try out the two free ferries across the Loire river?

[@RedHair651]

I grew up a couple stone throws away from the westernmost one of these :P

[@paulpinecone2464]

@Edward Lees Wait, are you saying the ferries ran on wheels?

[@paulpinecone2464]

@@RedHair651 Wait, are you saying the machine threw stones? Like a trebuchet kind of thing?

[@user-tr2dh4xx6u]

@@paulpinecone2464 ...

[@kepler186f4]

Ah yes... another knowledgeable adventure with Tom!

[@pablolovesmc2429]

ok i didnt notice anything about it in the video but are those airfoils on the ends? if so do they make it heavier or lighter

[@glypnir]

Simulators are so much fun for nerds. Back in the 70's I read a book that was a catalog of simulators. I remember avalanche simulators. And South Africa had a hailstone simulator. I suspect that there are a lot more now. I did a little work in a wind tunnel that was trying to simulate the planetary boundary layer. I found a hill in Israel that had been instrumented and built a model of it on the scale of 3/4" = 10 meters and compared the results. They weren't very well matched. I grew up in the pothole belt in the US, where there are 50 freeze thaw cycles every winter. I wonder if there is a simulator for that? It really eats highways and building materials.

[@computer_toucher]

I LOVE stress testing tech, and this was a deep cut -- never heard of something like this. Nice!

[@yolocupcake1001]

I want to start by saying that I don’t mean to discredit you or anything I just have a question. When the machine is spinning in one of your shots the motion blur ‘feels’ different then it should. Did you shoot shots of it spinning with a higher fps camera. But then used a camera with lower fps to film you talking? Because I feel like the motion blur on your hands is different then the machine at 4:01. Also feel like the motion blur is different when the camera is on the machine while it’s spinning. The colors also might be a little off. But that might just be my tv. TLDR: Did you shoot shots of the machine spinning with a different camera then the shots of you talking?

[@jimmlynden2261]

Great one, Tom

[@abarratt8869]

That's fantastic! And, judging by how good French autoroutes generally are, one has to conclude that they get a good return on running such a machine.

[@therealcaldini]

True! I wish Edinburgh City Council would get one. Or, y’know, just copy the French.

[@MonkeyJedi99]

Good roads are also a touch easier when you don't have a 2-4 foot deep freeze line in the ground pushing things around under your paving material every winter.

[@vukkulvar9769]

@@therealcaldini Or just make a deal to use the one the French have a bit. It could be cheaper yet yield positive results.

[@Kruxien]

Most of the french autoroutes are now private and own by the company "Vinci" wich made a deal with France a few years ago. The country loses a lot of money with that deal and we have to pay a lot of money just to go on some of our autoroutes. I mean, yup they are qualitative but it comes at a cost for drivers and the country 🙁

[@whannabi]

@@Kruxien the country? You mean the people. I don't think the government really cares especially recently as everything is going private with you know who I'm talking about.