When sensible speeds are banned
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- Опубликовано: 17 май 2023
- Brian McManus, Sarah Renae Clark and Nicholas Johnson face a question about a road trip with an added hazard.
LATERAL is a weekly podcast about interesting questions and even more interesting answers, hosted by Tom Scott. For business enquiries, contestant appearances or question submissions, visit www.lateralcast.com
GUESTS:
Brian McManus: @RealEngineering, / thebrianmcmanus
Sarah Renae Clark: @SarahRenaeClark, / sarahrenaeclark
Nicholas Johnson: @TrickyNick79, / countlustig
HOST: Tom Scott.
QUESTION PRODUCER: David Bodycombe.
RECORDED AT: Podcasts NZ Studios.
EDITED BY: Julie Hassett at The Podcast Studios, Dublin.
GRAPHICS: Chris Hanel at Support Class. Assistant: Dillon Pentz.
MUSIC: Karl-Ola Kjellholm ('Private Detective'/'Agrumes', courtesy of epidemicsound.com).
FORMAT: Pad 26 Limited/Labyrinth Games Ltd.
EXECUTIVE PRODUCERS: David Bodycombe and Tom Scott.
© Pad 26 Limited (www.pad26.com) / Labyrinth Games Ltd. 2023. 
Развлечения
The cat study has some confounding variables and may be a case of survivor bias. As Tom says, it was a survey conducted at veterinary hospitals, and dead cats will not be brought to the vet at all, and so will be omitted from the study. Nor will completely uninjured cats.
This person sciences! 👍🏻
It could still work if you're gauging the severity of the injuries. Minor vs severe vs delayed fatal (as in, lives for a few hours/days). And, given peoples attachment to their pets, I would expect at least some to bring in their dead cat, hoping that its merely injured. Or the reverse for an unharmed cat: the owner could be worried that it could possibly maybe have a chance of being hurt, so they take it to a vet. I wouldn't expect big numbers from either group but it'll be non-0.
@@dgthe3 There is also terminal velocity to take into the calculation. Above the n:th floor the cat will fall at the same speed approaching ground, be it from the top of Empire state building or the edge of space. The later would kill the cat for other reasons of course, but the cat would hit ground with the same force. Anyway, don't throw cats from space!
@@klutttmuttsprutt6087 I do believe that a cat's non-fatal terminal velocity only applies if it consciously positions itself in a certain way, outstretching limbs etc., which a cat that has already frozen to death in the lower strato- or upper troposphere won't be able to do anymore. So there's every chance that if you drop a cat from that high, it would actually just tumble down after it dies, and approach earth's surface at a terminal velocity that is above the speed required to kill a live cat.
You know, I came into the comments section to rant about harmonics, resonance frequencies, angular momentum, terminal velocity.
But this made me realise I was the one to be corrected.
People actually die more often from falling from bed than they do jumping off skyscrapers.
I have been humbled.
Tom: Hikes to a volcano.
Volcano: [had stopped erupting]
...
Tom: Travels to an Ice Road in Estonia.
Winter: [had not frozen the water]
...
😯
*has not frozen enough of the water... look up "Tom fell through a frozen lake in Estonia" for more details.
Neither hot nor cold ... Tom identifies with God! Rev 3:16
Tom: makes a video about an asteroid on collision course with earth
Asteroid:
@@ArifRWinandar 2029 called
seems like we'd better keep Tom away from Antarctica in case his presence speeds up the melting of the ice sheets there
for once, those cheesy history channel shows taught me something. the moment brian mentioned ice road trucking, i remembered that you can set off underwater waves which will burst the ice in front of you and i was squirming in my seat like a child waving his hand around so the teacher picks him.
Yeah, I got it immediately. Partly because of Tom's video, partly because I know about resonance frequency, and I assume at one speed you'll just be pushing an ever growing wave before you. Which isn't ideal for the brittle ice in front of your moving vehicle.
Me, too - standing at work yelling “harmonics!” in my head 😄
Yep at certain combinations of velocity, amplitude (weight), and distance from the edge your wave harmonics will cause the waves being created by the vehicle and the reflections off the shore combining in constructive interference. And as Tom indicated by ABS wave harmonics come into everything from breaking to the operation of the engine to how traffic works…it’s all modeled in wave mechanics. Fun fact, as asphalt is not 100% solid (tar is technically an extremely viscous fluid) wave harmonics impact wear on the road. If you have ever seen waves worn into a roadway those are usually caused from the repeated suspension movements of heavy semi-trucks trailers at that point from either breaking or an initial bump/dip in the road.
And also the unbuckling of the belt and driving with one hand near the door handle is recommended because statistically the risk of death from falling though the ice and not escaping is greater then the risk caused by not having both hands on the wheel and dieting in a car accident. So in those conditions you are taking the less risky option by preparing for the more likely issue by disabling normal safety features/practices.
1:31 The moment they figured out 90% of the answer I _immediately_ figured "oh okay, it's because of vibrations that would break the ice". Then they spent the rest of the video _not_ figuring that out until the end. XD
It creates waves of water under the ice, that damage the ice. Or atleast that's how Ice Road Truckers explained it.
I just thought it would be the resonance frequency from driving itself, like those pedestrian bridges that wobble when people are walking in step, but with multiple cars going at the same approximate speed. But I guess it has to do with the frequency of the pumping anti-lock braking mechanism?
Finally a question I know the answer to right from the start. Being from there helps ofc... :D
I was thinking it was crazy that everyone didn't know what ABS does, but then I remembered I drive a car older than me that doesn't have such features. Knowing you need to pump the brakes with out it is pretty essential and it's probably more of a generational/forgot -type thing.
Ohhhhh! That makes a lot of sense! Yes, I too learned to drive (in Canada) in a time before ABS was widely/commonly available, and I totally remember being taught how to pump the brakes in icy/snowy conditions. To me it's just intuitive that ABS would be doing the same thing. But if you never learned to do that in the first place...
Also, so far I've never had to brake hard enough to activate the ABS in my car. I happen to know in theory what it does, but I can imagine a lot of people who aren't so technically minded would have no clue.
I must have got my license before ABS was common, and nobody ever explained it to me. My education on ABS comes from feeling that judder in the rare occassions I need to brake on ice, and thinking "oh, that must be what ABS is".
I know how ABS works, but couldn't figure out why that was relevant... 🤦🏻
I guess Bri'ish "Driver's Ed" doesn't teach them whet ABS does.
I really respect Tom for immediately realizing that *he* was the weird one for knowing the obscure information, as opposed to everyone else being ignorant of a common fact, and deciding “i will stop being exasperated now”. that takes a good amount of self awareness
This was something that at least Finnish driving school does teach. So for us it is actually common knowledge how ABS works. And I never would have considered that English driving schools don't teach that.
@@vissenekku English driving schools don't even take you to the motorway, so not surprised 😅
@RuboStars they are supposed to now. But I'm sure this was something I learnt in Physics classes (perhaps A-level) but definitely in school at somepoint.
Coming here for more lateral puzzles just after watching Taskmaster is such delightful timing
Taskmaster is comedians trying to be smart, this show is smart people trying to be funny. It's a nice contrast. Also this show is just thinking until you get the answer with a few hints, Taskmaster has no time to think or hints so you need to act.
@@bilalrasool2318 Oh, Taskmaster has plenty of hints. Sometimes the contestants even spot them!
This happens on dirt roads as well. It is called washboarding where the car suspension enters into a resonance with bumps in the road and makes them worse over time.
im a touch concerned about the lack of knowledge on ABS... btw its why on an offroad vehicle you can turn it off, because on loose surfaces i.e. gravel/mud ABS thinks it is always slipping so it refuses to brake
I think its because on some car ABS exist and can´t be turned off, or it does not exist.
that or the way to turn it off is just so convoluted.
I believe in some vehicles that toggle between 2WD/4WD electronically (such as the Nissan X-Trail (International)/Nissan Rogue (North America, X-Trail T32)) whilst it starts up in 2WD mode by default, once you toggle it to 4WD mode the ECU and related computer gear will turn off the ABS.
Checking the manual for the 2003 X-Trail T30 I inherited from my dad - it states that the car will start up in 2WD mode (the 4WD indicator will light up initially but turn off), but may automatically switch to 4WD mode depending on driving conditions (4WD indicator will light up and stay lit whilst in 4WD operation), otherwise the driver may manually engage and lock 4WD operations whilst stopped with engine running (manual warns against engaging 4WD mode with moving front wheels, as it is FWD in 2WD operation, and against engaging 4WD during turning or reversing).
The manual also says that ABS won't kick in when travelling around 5-10kph (3-6mph), which would be the sort of speed one crawls at when driving off-road.
I can turn it off in my Peugeot 206 CC, which DEFINITELY isn't an off-road vehicle.
"The ground floor?" 😂
Being a Matt and Tom fan, this was a very easy question.
And here I kept wondering: How does The Boot (of Estonia/Russia) play into this??
When I was learning to drive my driving instructor had me go to a safe road in the middle of nowhere and then crank on the breaks hard enough to activate the ABS and feel what it was doing so I'd always remember how it works and when it'll work. It definitely stuck lol
I am old enough I had to train emergency breaking without ABS. On an asphalt road with soggy leaves in the autumn. That was en experience keeping the car under control.
*brakes
My flight instructor did something similar.
Nowadays students are taken to the beginning of a stall and told to notice the sensations that precede a stall. However, they're distracted by the warning horn that goes off at the exact same time.
Back then he took us to a high altitude and had me execute a complete stall. I never forgot the characteristic vibrations that precede the plane stalling and starting to fall out of the sky,
I had two answers that I thought were separate. My realistic answer was that below a certain speed ABS would not turn on and allow the tires to grip without locking up, and over a certain speed ABS was not as aggressive for safety reasons. Then what I thought was my outlandish answer was that driving between those speeds would create resonant frequencies that would crack the ice. Somehow I managed to fail spectacularly by sort of answering both parts of the questions correctly separately and reaching the wrong final answer.
My 10-second guess is driving on ice roads because no seatbelt could make sense if you fall through. No idea how the speeds fit into that, though.
You made me think frozen lake.
Nerd!
If it's anything ever to do with speed in a certain range, or movement (stepping/ waves/ wind) in a certain range, it is always resonance.
My mind when to that 200meter or so bit of road in Europe where you could not stop the car.
because that piece of road is in another country.
and no one could be arsed to build a new road so they just went well technically and legally your in another nation.
but we will ignore it if you drive at at least this amount and dont stop anywhere between thoes two point.
so yes if you had the unfortunate that you car stopped on that bit of road you could not leave the car or even open the door (if so to kick start it).
you had to wait untill a boarderguard (they be armed and looked like front line soldiers) walk over to you and in angry asked why you stopped.
Yeah, my hunch on the top speed limit was that since it had been tested any weakening was likely to be subtle instead of immediately dropping into water, and that speed was enough to get clear as it gives way.
As soon as I heard the range and no seat belts the mechanical engineer inside me shouted Natural Frequency🤣
Having just watched a video on the 1940 Tacoma Narrows bridge, the resonance was my first thought.
I really love these videos
My original guess was sort of along the right lines. I assumed it was something like in Baja where if you drive faster, the bumps are actually smoother for the car since it only hits the top of them. And I've been to some frozen lakes and they don't tend to be very smooth, so I thought it had something to do with the vibrations from the car on the road.
I cant adequately explain why, but whenever I hear about an oddly specific speed limit on some stretch of road, my first thought is "oh there is something to do with resonant frequencies at play here."
Resonant frequencies were a minor fascination when I was a teenager as it was responsible for a host of weird, cool, and/or terrible stuff; from being able to shatter a crystal wine glass with your voice to bridges collapsing and how we get sick squealy hard rock noises out of heavily distorted electric guitars.
Oh shoot, didn’t know you had a vid with Brian McManus. Got really excited when I saw it lol
I got this one pretty quick - remembering Adam Savage tell a story about a Mythbusters episode about an army marching across a bridge that contributed to it swaying. If you have the right vibration rate (100s of boots hitting at the same time) you can do some damage. Great question Tom!
How a skilled singer can break a glass :)
This is the first one where i got it immediatly! Any time you're dealing with materials prone to cracking, it's gonna be resonant frequencies
Technically, if I remember correctly, knowing how anti-lock breaks work is one of the questions in order to get a driver's license in the US. Also my mom told me several times growing up how they work and how they saved her life sliding on an icy bridge in her 20's
I was never asked that question. For me the drivers test was just driving and not breaking laws. The written test was randomized the two times I took it and there were mostly basic questions about the signs and certain laws.
i mean it's cool knowledge but not necessary to know
*brakes
There is no standard test in the US, it would vary by state
The cat thing is also a bad conclusion because of selection bias.
It's 100% about the surface the cat lands on, something solid like concrete or asphalt and after a certain height you're not taking the cat to the vets at all.
Because the selection for the study was vets visits falls from higher floors more disproportionately represented cats landing on softer things like bushes which greatly increases the odds of survival with minimal injuries.
Specifically _survivorship_ bias. It's a textbook case, along with armor plating on the B-17 bomber.
@@ShankarSivarajan I love that B-17 bomber revelation because it makes perfect sense once you know the answer but seems so counter-intuitive that I couldn't imagine it being an independent idea generated by my brain.
Immediately know the answer. Because it reminded me of bridges collapsing due to resonance when people march over it. And the safety belt says water. And Estonia said ice.
I think this s the first one that I actually knew the full answer to as soon as he asked the question. I remember watching an episode of Ice Road Truckers (I think) in which they explained it.
Algo on point, Estonia mentioned
I also thought it was common knowledge how anti-locking brakes work - it's the same as how you keep brakes from locking normally, there's just an automatic thing to do it for you.
I also believe most people would know that there is not ice all around in Estonia.
@@57thorns Nah that part didn't surprise me personally
Oh it is common knowledge. They just didn't know it.
That's why I'm watching Tom's content and never heard of his guests. Tom is reasonably educated and curious of the world around him.
@@rageagainstthebath He had never heard of Hagia Sophia though. That a knowledgeable and well-traveled person like him didn't know arguably the greatest wonder of the medieval world still astounds me
It's all about tuning. Getting the adequate frequency for Jingle Bells🎶
The circumstance is called The Speed Clause, usually applied to busses
0:14 That sounds like it's rules for crossing a frozen lake. You don't want to be struggling with a seatbelt if you go through. And you don't want to go a medium speed because that probably causes resonance which can break the ice.
5:24 You have to time the undercurrent that’s created either slow or fast I’m the middle can cause a wave under the ice possibly damage it.
I love the idea of dinner Chad researcher somewhere just chucking cats from balconies😂😂😂
I wonder if Tom has got another set of flights to Iceland booked yet? 🌋
I was thinking friction. There are two intersections across the main road off my street that, in heavy rains, become hydroplaning traps. If I remember them when I'm too close, there is no use in slowing down unless I'm going to really lay on the brakes, because if I can't slow down enough to get some friction, like under 20mph (~30K), the momentum will keep the car moving forwards long enough to get me through, without noticeably floating sideways, *if* I'm going about 40-45 (~65-70K).
That kind of makes sense, but you have to go really quick to skim the surface. Too slow, and you don't create a bow wave. I'm that range, you flood the engine 😂
@@PianoKwanMan :
I don't know how whether this helps to prevent that, but I let off the accelerator once I get into the water.
Ice roads is a thing here in Sweden as well, so this was an easy question for me. 🙂
Not in my part of Sweden, so I struggled! People walk and skate on the ice of the lake near where I live, but no cars allowed. I do find it funny that people would think there might be parts of Estonia covered in ice all year round though...
I have the education levels of a cat and I worked that question out in the first 30 seconds!! Come on!!
Also, how ABS works is absolutely common knowledge. Everyone is supposed to learn this in drivers education.
When I heard it was in ice road I instantly thought of the vehicle weight making a wave under the ice and if u go at the correct speed the wave can compound and break the ice
Now the question I have is why isn’t that a thing in, like, Finland or other countries that have ice roads
Mid-guess : Getting chased by bears and/or making resonant frequencies to the ice.
The remake of Dante's Peak starting Tom Scott is a bit of an anticlimax.
Going fast on ice sounds like fun, but also dangerous.
My family went to see motorcycle ice racing when I was a teenager and you're right, it looks INCREDIBLY fun. Maybe dangerous too. Just a little. 😅
I guess they don't show Ice Road Truckers in the UK. I don't normally watch it, but saw that (or some other documentary) where they showed people and trucks driving on an ice road in Canada. They mentioned no seat belts, and don't drive at a certain speed because it creates a pressure wave.
As soon as he said ice road, I was thinking, "oh yeah because it's going to cause resonance problems with the ice, sort of like bough shock" and then proceeded to spend multiple minutes waiting for them to come to that conclusion lol
Tom I think you've made a video here so I know it
*Edit he didn't get to make the vid but they talked about it on a park bench I think*
Awesome
3:46 Well, he may deny it, but he seems like a nice engineer!
My initial guess was if it's opposite day
Nicholas Johnson, this is the second time I have listened to your voice while doing something else, I put the video in background while I do other stuff, You sound remarkably like Matt Damon. I feel like im listening to a Jason Bourne Movie.
Driving at 36 km/h (so in the upper part of that range) corresponds to 10 m/s. If a regular car has about 3.3m distance between the axels, this will take 1/3 of second and set up a 3Hz vibration in the ice. I'm guessing 2-4 Hz would be around where you get maximum sheer loads on the ice?
Not totally unrelated, I have crossed a fjord in Svalbard/Spitsbergen on a snow scooter/snowmobile (obviously on ice+snow), doing about 30+ km/h when I noticed that I was starting to sink a bit so I immediately speeded up to about 70 km/h and the rest of the crossing was fine.
This topic, the ice road in Estonia, was also a topic on one of the older shows of Quite Interesting. I believe the ice road was referred to as "Kool Grinder", just to create some humoristic comments before the question was answered (the question was phrased as "What is a Kool Grinder?").
I can't remember why I know this, but I've definitly seen a video on this somewhere.
Where can I watch the whole episode?
the Bond movie where Russians fall through the ice is The Living Daylights
Tom also has experience falling through the ice in the same trip
There seems to abe a lot of confusion here because of toms comment on the ABS. What happens that makes it undafe to drive at these speeds is essentially like a sonic boom where the water under the leading edge kf your car cant get out of the way fast enough and builds up pressure. There might also be a factor of the distance between your frint and rear tires creating constructive interference
I remember reading about the Cat Study in physics class, and was very concerned until read the details of how the information was obtained.
Where I live, once the ice road is open to 40,000 lbs, I know I can drive whatever speed I want in my 2500 lb subcompact or 4000 lb SUV because it's like a mouse compared to a bear.
How does no one explain it with the words resonant frequency?
Tom Stanton has videos trying to add ABS to a bike. That can be helpful :)
I feel like the question was written in such a way that it purposely didn't rule out various types of vehicle, so that they'd have to narrow it down to definitely cars (and/or normal road vehicles) first, and thus they may welll have got sidetracked with guessing about other vehicles first, but then Tom specifically narrowed it down for them before he let them start guessing, only to then be astonished when about 90% of the answer was then guessed really quickly.
Resonance sounds weird to me, like that implies that hitting a particular frequency is what causes the issue, but the problem is speed not frequency. It makes me wonder if it's actually about creating a bow wave on the ice, and if you drive much slower or much faster than the speed of the wave you're creating there's no problem, but if you're going the same speed as the wave you get constructive interference and the ice breaks. Like a sonic boom
I'm old enough that I was taught how to pump my breaks just in case my vehicle didn't have ABS
Until you mentioned the answer, I was thinking it was because of hydroplaning - the ice top that melts because of cars driving over it becoming a thin film of water, and at a given speed, your car begins to lose traction with the ice, and just essentially begins to float on the film of water on top of the ice.
That said, I couldn't exactly square it with why the higher speed minimum was in place - the best I had was that you drove fast enough to not be able to hydroplane, or that if you did hydroplane, you'd be guaranteed to cross the hydroplaning zone safely just by sheer speed.
Calling Baltic SEA a big lake is funny
So... it's a safe zone around the resonance frequency of the ice, yeah?
In Germany you learn how ABS works in driving school.
Gonna call it driving on a frozen lake
Let's go Brian McManus. Engineers represent
The mention of the ABS actually made me think the answer was going to be traction control, like maybe the traction control system only does the thing at those speeds
My guess after "Ice road" was "something to do with how the ice bounces/wobbles underneath the car" which is literally just resonant frequency in layman's terms
It was also a plot point in Billion Dollar Brain.
"Road conditions: reopened to marine traffic"
ABS is common knowledge btw.
in germany you even need to know how it works to stand the drivers license.
I would say that knowing that ABS breaking works by braking on and off very rapidly IS common knowledge. I have almost no mechanical or scientific knowledge. However, I do also live in Canada, so perhaps it is more common knowledge in countries that have more serious and lengthy icy conditions? Then again a scary number of people don't bother to put on winter tyres, all seasons don't cut it. Anyway, I enjoy that I got to the answer way ahead of everyone in the video because more often than not I don't!
I'd just like to add that the University of Antwerp in response to this study posed an interesting follow-up question: Given that we know cats tend to land on their feet if you drop them out of a window, and given that we also know peanutbutter sandwiches tend to fall with the peanutbutter side down, what would happen if we would spread peanutbutter on a cat's back and dropped it out of a window?
Got it before Tom repeated the question. Ditto the suitcase-out-of-the-train-window one. Either I'm a genius, or this series depends on the participants being unusually unworldly. And I don't think it's the former.
Ah, so that's what those funny little letters mean
That resonance has *nothing* to do with ABS and everything to do with the car being heavy and causing a bow wave. I imagine it's also dependent on the thickness^Wstrength of the ice (related but not the same), the weight of the car and so on.
Or frozen lake!!
Wait, is this why Clarkson floored it throughout most of the Top Gear Polar special?
As a physicist who has been taught about resonance and heard stories of many a bridge being destroyed by it I was immediately able to answer the second part of the question, but I get that it probably isn’t common knowledge
Tom, teh volcano is about to erupt, i have flight going out on the 19th, pls come before that so you can stop the volcano for us to be able to leave the country :P
About the cats and falling..... Mine jumped after pigeon from 14m on concrete. Result: 1 broken leg. Not sure about other results. Anybody have link to these studies please link in reply to this comment :*** Would love to know what the record is :D
8:04 what a missed opportunity. They should have done the test properly themselves with live subjects.
I can't believe that Tom didn't also mention how he fell into a frozen lake on that trip.
I'm not sure he really likes to talk about that...
Ok my guess for the second part about speed is that the car sends vibrations near the resonant frequency of this type of ice
edit: nice
First guess< Are the driving on ice? I know from ice road truckers that you don't wear a seatbelt.
Does a cat really have seven lives, or is that just a superstition? Find out next on Mythbusters! :D
5:35 you did that gesture bc of lightsabers
I think it's funny that the title is 'when sensible speeds are banned' as if driving over 40 km/h (25 mph) isn't sensible when you need to go 12 miles. I'd probably be doing 40 mph (63 km/h) if I was driving on that sort of road.
Writing the captions isn't my forte :/
spicific frequency
A lot of this podcasts becomes trivial if you've watched QI and/or been an avid reader of Cracked.
My initial guess; it's something like the roads in Australia where the dirt roads have developed into basically a sin wave as a result of the traffic and lack of maintenance over time. I'm imagining seatbelts leading to injuries, the low speeds helping prevent making the situation worse, and the high speeds basically letting you drive along the ridges.
ABS pulses the brakes to allow turning, not for locking up. The skidding/sliding of tires cancels out any availability to steer and maneuver the vehicle, similar to hydroplaning. Allowing the wheel to rotate even slightly increases the traction needed to turn and enables the driver to steer and slow down as fast as possible.
How do you not understand that these are the same thing?
ABS is designed to prevent the brakes locking up, *because* that would prevent you being able to turn.
nice
"You must NOT wear a seatbelt" Must/must not is a false friend (for German and probably a number of other languages)… but what really annoys me is that "must not" is NOT "not (must)". In German, "du musst" and "du must nicht" sounds like the equivalent, but "du musst nicht" means "you don't have to". So the opposite, logically(!), of "du musst" ("you must", "you have to").
Car wash?
I'd like to see the car wash you can go 50 kph in!
@@SirExal Hehe true I posted that a second after hearing the question so I hadn't realised that you could go over that limit.
Without finishing this video, is it this the video you covered with the falling rocks area where cyclists aren't allowed onto it? I feel like, if anything at all, that road, with rocks falling and you being on said stretch of road, would be justifications for such wonky conditions.
Wasn't that in France?