Stoplight BOUNCES itself to pieces!
ฝัง
- เผยแพร่เมื่อ 3 ก.ค. 2024
- A gentle breeze can make a traffic signal fall onto somebody's head. Especially those really big stop lights along America's wide roads. I talk with three traffic signal experts who work to keep traffic signals safe.
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Factual sources:
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"Reducing Fatigue in Wind-Excited Traffic Signal Support
Structures using Smart Damping Technologies," Richard Christenson, University of Connecticut, Jan 2011. onlinepubs.trb.org/onlinepubs...
Interview with Carl Macchietto, Valmont Structures, 29 Nov 2022.
Interview with Mark Taylor and Adam Lough, Utah Department of Transportation, 17 Apr 2023.
"Fatigue Design Categories For Pole Structures," Design Memorandum, Washington State Department of Transportation, 19 Apr 2011.
www.wsdot.wa.gov/eesc/bridge/...
"State Route 160: Multi-Year Expansion Program," PowerPoint presentation to the Nevada State Legislature, 10 Feb 2006.
www.leg.state.nv.us/App/Inter...
"Staker awarded long-awaited SR-36 project," Karen Lee Scott and Troy Boman, Tooele Transcript Bulletin, 27 May 2004.
"Erda sign raises SR-36 worries," Karen Lee Scott and Troy Boman, Tooele Transcript Bulletin, 2 Sept 2004.
"Attentive driving key as SR-36 work proceeds," Karen Lee Scott and Troy Boman, Tooele Transcript Bulletin, 30 Sept 2004.
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Galloping videos (with permission):
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"Wind has the traffic light bouncing," @zj_rides117
• Wind has the traffic l...
"Wind shaking traffic light heavily," @52_Pickup
• wind shaking traffic l...
"Stop Light Blown Down By Strong Chicago Winds," @devodare_chicago7748
• Stop Light Blown Down ...
"Strong Wind Shaking Traffic Light Pole," Samroon Vlog
• Strong Wind Shaking Tr...
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Time sections:
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Stop lights can fall down (0:00)
Trouble in Tooele (0:40)
Galloping fatigue (3:16)
Nevada's fat paperclip (5:50)
Vortex shedding (7:45)
Reduce galloping (9:12)
Harmonic resonance (12:01)
Valmont Mitigator TR1 (15:12)
Not an ad (17:48) - ยานยนต์และพาหนะ
Road guy rob! I love your videos. Unlike most educational videos you actual go to the source and film in the field rather than doing it all with voice over and stock videos and photos. I really appreciate all the work you do for your channel. Keep up the great work!
Exactly!
Thank you! It's very time consuming. Glad to hear it's worth the effort!
@@RoadGuyRob You're a very unique channel on the internet, which is saying something! Keep up the great work!
Love and respect from Nebraska!
@@RoadGuyRob i love your videos more than Not Just bikes’ videos. You present information in an interesting way that is entertaining and less “wah” moment than some urbanist channels.
@@charlesrodriguez7984 He offers a moral destination to walk towards.
I focus on the first steps cities/states can take on the journey.
Mysteriously all 4 stoplights collapsed at an intersection right before I approached it in Cobb County, Georgia back in March. It was one of the strangest things I have ever seen.
That is odd. Sinkhole maybe???
Final destination stuff there.
Where at?? I live in Cobb myself!!
@@thewindowisrusty the intersection of Busbee and Barrett Pkwy. Wsbtv did a story on it. Very odd.
@@guriausa Oh wow. That is one heck of an intersection for that to happen in. I am on the Austell side of Cobb, but even I know where that is!
It's not just natural wind. Back in the '90s New York's DOT found an overhead sign structure that was bouncing every time a truck went under it. They inspected it and found it was starting to crack.
If I recall right, they changef their design standards to mount the signs higher, away from the trucks' wind blasts, and made the supports stouter.
The damper in the video addresses trucks going under it. Thats interesting
Illinois DOT also requires new overhead sign structures to be higher. I've noticed new ones are placed higher and that must be part of the reason why. Nice!
In Europe we just place two poles if the traffic lights spans more than 3 lanes, one pole on the side and one pole on the refugee island.
they are also close to the road on both sides, in America we like to run into things close to the road, lol especially ford mustangs
@@chrism3784 That's because you have unprotected high speed roads everywhere. Where I live, every road faster than 50 mph (80 kmh) is surrounded by guardrails, so you don't need a huge "clear space" to not run into things. And you typically don't see lights on 50mph "main roads" at all, because they usually meet inside a town or village, where there is always a 30mph (50 kmh) speed limit. If there are faster roads through build up areas, they will have very few entries and exits, and will typically have some grade separation, with some overpasses or even tunnels. If it doesn't have those things through a built up area, it will be a 30mph road.
So in Europe there's much less collisions with peoples houses and stuff like that, not because we're better drivers or americans are idiots or anything, but because speeds are either much slower or there are physical barriers. It's the difference in how the infrastructure is built that makes all the difference.
@@phillipbanes5484 Where did I say Europe is a country?
@@phillipbanes5484 I just say how we do it in Europe, all countries of Europe. I have been in all countries in Europe so I know.
I can't tell for Africa or Asia because I haven't been in at least half of the countries in Africa or Asia.
@@phillipbanes5484 What is your problem? is the "America is the best country in the world" propaganda wearing off?
Can't you handle that you have to hear that on the internet? Wish you had 8 weeks of paid vacation a year so you could actually find that out for yourself...
Well enjoy the cracks and potholes, unaffordable education and health care in the worst OECD rated country in the world.
Rob on a swing set being pushed by a gorilla. This makes my day.
Great content about the wind vortices and how they work against the poles.
All the kids disappeared when their moms saw that strange scene
The wind vortices/resonance frequency were actually my first thought as to why it was happening; I'm not a genius, I just like physics :p
Where I grew up, all traffic lights were strung on poles with wire. Logically, I know that they must be safe enough, otherwise we wouldn't use them, but I've always thought that the poles seemed like such a death trap by design. So much strain on these poles constantly.
I live near a wide and busy US highway and they have used steel cables across the intersections since the 1970s and I have never seen them gallop. They also have never failed. After many years, they replaced them with new cables. (normal maintenance). The new ones had the exact same design. So, it seems to work very well in this situation.
They can actually be safer sometimes because they have less cross sectional area to face the wind so a lower wind loading.
Modern intelligent systems depend on camera or radar sensors to manage traffic signaling on-demand to increase intersection throughput and save fuel and pollution from idling cars. Those sensors have to be mounted on a fairly steady structure. They can't be on cables swinging in the wind.
@@MikeV8652 the cables are hung by metal poles, and the cameras or sensors are mounted high up on their own smaller arms above the road, so the sensors and cameras are on an arm and the signals are on cables below them.
@@jackfeldman3916 That should work. I'm familiar with the sensors being mounted on vertical tubes that run upward from the solid signal arms here in Texas.
Would love it if you did a video on guardrail and guardrail types next and why certain types are used in certain spots of roads and freeways.
Yes it does appear There's a lot of technology on the guard rail end caps.
We had a problem in Virginia (and several other states) about a decade ago with the guardrails being too rigid. Instead of crumpling in a head-on collision and pushing the rail out of the way, the end of the guard rail stayed in place and went through the windshield and the driver's face. Lawsuits found the manufacturer had made an unapproved, undisclosed modification to the design before installation.
@@tvdan1043 I've seen a couple of videos of a guy checking guard rails and finding that they have been bolted/installed wrong. He explains why and then reports them to be remedied. TheGuardrailGuy. Installers don't always understand the thing they are installing.
@@gwaeron8630 yes, I read the guy is convinced his young daughter, while driving, died needlessly because she collided with a guardrail that was installed/repaired incorrectly. He’s been on a self imposed vendetta of sorts to expose the complex engineered guardrails need for competent installation….
Andrew Lam has a good video on road barriers including guard rails.
There's a bit of engineering nugget of wisdom that was kinda glossed by.
When you have two oscillators coupled like the tuned mass damper & the building or the Valmont Mitigator & the cantilevered traffic arm, any oscillation between either are passed between the two continuously. However, this energy passing back and forth idea can only happen if the resonance frequencies between the two are reasonably similar.
Passing energy between the two oscillators isn't actually that much use, but the important part is once you move the energy into the tuned oscillator, you can dissipate the energy through dampers, which are like shock absorbers for cars.
The weird thing is if you put too much damping, the energy doesn't get coupled as much, but if you have too little, then the oscillation is harder to remove. Also, the more you add damping, the "resonance frequency needs to be reasonably similar" requirement becomes more relaxed, which makes it work less effectively but over a wider frequency range.
It looks like Valmont's approach is to add a butt ton of damping so that it works over a larger resonance range.
Good insights, thanks
adding damping also changes the resonant frequency, and I bet the magnetic damping is variable because you can make the weight magnetic and put a variable resistor on the coil it's interacting with. That way you could actively tune it to match the frequency better. At least that's how I would design it.
It's actually done so that the poles and arms can be down sized as a feature of mounting these devices.
Actually, I'm pretty sure the real clever bit with Valmont's approach is that because of the way the electromagnetic eddy currents work between the magnet and aluminum tube, the amount of dampening applied actually _changes depending on frequency and magnitude of the motion._
Which is actually a really neat trick, IMHO, and a great practical application for what is often just presented in science classes as a "weird thing you can do with magnets" for a couple of minutes before moving on to other stuff...
I live in Wellington NZ, known for being the windiest city in the world (by average wind speed), and recently several street lamps started drooping and falling over because... they forgot to account for wind when designing the adapters and they now have to replace 17,000
Do they have horizontal signal heads in New Zealand? And if so, is red on the right, like it is in Japan?
He featured horizontal signal heads from Japan, and they are opposite that of the US. It's either because they drive on the left, or because their writing line breaks are to the left, or both.
@@carultch They are all vertical.
@@carultch Probably because Japan drives on the left. In Singapore the red light is on the right too, while in Taiwan/ROC its on the left instead (where they drive on the right instead). I've also seen vertical overhead traffic lights in Japan too though, mainly in the more northern regions with more snow, with less surface area for snow to accumulate on with a vertical design
Australian traffic light systems do not tend to have one lantern per lane. Large intersections needing more than one lantern per direction across the intersection tend to have a median so a second set is mounted there, so large gantries/cantilevers carrying stop/go traffic signals are rare here.
Gantries and big, solid cantilevers are used on ‘smart’ roads and freeways/motorways and they are generally HUGE!
Yes I've never seen a traffic arm swaying in Australia, (except for once I think in extremely heavy wind) and I've never known them to fall over except when someone crashes into them
It is because they 1) assume drivers would DIE from the inconvenience of looking even slightly to the side, 2) maybe their roads are so complex that each lane needs a specific light timing, or 3) they think they serve as backup.
Here, I also only see the stoplights working in groups. One unmarked light for traffic going straight, and maybe one arrow light for each direction in a crossing. If all timings are the same they just mount two lights (one proper on a horizontal pole, and one backup directly mounted to the main vertical pole).
Biggest mast arm I’ve seen is in parramatta
@@petergreenson Where is it? I would be interested to see it
@@pwhnckexstflajizdryvombqug9042 Okay, its more of a gantry with lanterns on it - but Henry Lawson Dr / Hume Highway
Wow at 15:27 the tech specs on the TR1 damper are great. I expected the pneumatic stuff, but the inclusion of the magnet to create the eddy currents against the aluminum housing was just icing on the cake. Very impressive.
Yeah... Totally was thinking the same thing...
And Valmont is less than 10 miles from me, here in Eastern Nebraska, just NW of Omaha.
They are working on other dampers for street/area light poles as well. Really cool stuff.
Completely passive, and very little maintenance!
I want to point out that @thisoldtony has a good video on rotary and linear dampers for anyone interested in more information
"a normal traffic light pole you can give a hug"... that is like... 5x thicker than a "normal" one
Nebraska is the windiest state.
Here in Omaha, larger intersections have diagonal trusses over the roadway that hold all the overhead signals and signs, similar to the single tube shown that goes over the road in the video, but lighter.
15:18 I've seen those on traffic signals here in Omaha. I had no idea what they were at first, and then decided that they had something to do to mitigate wind load. But I had no idea what they had inside them! Yay Valmont!!
We have those in a couple places in Kansas, too. The city of Lenexa added diagonal trusses along 87th Street Parkway (I know, pick one or the other, right) at the SPUI at I-35 and at the intersection with Renner Road, just west of I-435. And they're designed to be aesthetically pleasing, not just big aluminum tubes. The one at Renner is made in this curvy S-shape with little tails on the ends.
We have some in Texas too. I don’t know how they aren’t where I live considering I live in the 3rd windiest city in the US.
Cool, sounds steampunk AF.
Also I'd bet that a truss, with all its crazy angles, doesn't suffer from vortex shedding that a straight pole does.
Yeah, I’ve seen one of the gantries on Dodge Street/US 6/Grand Army of the Republic Highway in person (not sure why we didn’t come in on I-680 like usual). They also have gantries like that at the SPUI’s with highway 77 in Lincoln (although they’re not diagonal)
There's another solution that wasn't mentioned, but which is applicable for any setting in which you have a non-traversable median. You can use a post-and-lintel mast arm arrangement. Rather than having a cantilever (arm fixed at one end, free at the other end), you can have it fixed at both ends. This reduces the degrees of freedom in which the mast arm can move, and it also negates the problem of uneven weight distribution inducing very intense loading at the mast arm's attachment point. It's not necessary to build a single extra large support structure, it's doable to build multiple smaller ones, likely at a lower overall cost and with fewer installation headaches.
I did wonder this as well - particularly as this was the design chosen for the intersection featured with that 200' span.
I have to admit, I love the idea of using electromagnetic eddy currents to make a more "universal passive dampener". I never would have thought of that particular application, but it's really cool.
I think our traffic poles in Australia mitigate this issue by having a single signal head that shows both straight and left turn movements in combination with stand alone vertical poles erected showing these movements. Probably costs less or the same as building one giant arm
Depending on how they're going about it, it might cost more just because running wires underground to more poles is a bit more complicated than just stringing them all together on the same pole. Well, for simpler intersections. Not having an entire set of lights for every lane would more than make up for that at multi-lane intersections, I think.
We also don't need a unique set of lights for every lane. If you have three lanes that will only ever move in unison (say, going straight) they'll all just share the one set of "going straight" lights. That way we don't need to get any lights into the middle of a huge intersection to begin with!
@@laurencefraser that'd require critical thinking skills
It's funny because there are some intersections, (mainly in Melbourne) that have 9 lights all in the same module, and one in the city that has 12, with a few extra beside them.
Vortex shedding is the reason you see those spirals on tall, thin structures such as radar masts, industrial chimneys and old school car aerials. I'm guessing engineers had no success with the same here.
Btw, note the corners on Teipei 101- they have a nice decorative cutout on each corner. This was actually designed later on in the process to address an issue with vortex shedding creating low pressure zones on the downwind side of the structure that were calculated to be strong enough to pull out windows. The cutouts on each corner disrupt the shedding to prevent these from forming, and the counterweight acts to stop the building moving unacceptably.
Back to the signals, though - I wonder why not simply have a whole-road-width monotube? We have them holding up signs on the highway... If there's 2 upright components, the arm physically can't gallop
Coming in late on this, they're called helical strakes and it could be that they just didn't think about using them on horizontal structures.
Here is a fantastic idea for a video. Road hazards that go unresolved or unnoticed.
For example, on the George Washington Parkway in Virginia, just outside of Washington D.C., there is a stretch of road that has an almost glass-like road surface that becomes as slick and dangerous as black ice with even the slightest amount of moisture. Even high humidity turns this section into a skating rink. I used to drive a car with all wheel drive to work along that stretch and even with AWD and traction control I spun out more than once. Well, maybe not spun out, but I felt loss of traction and could have lost control with the wrong reaction or any kind of over correction. I've seen it happen to countless vehicles along that stretch. There are always accidents and pileups, almost every day. From Roosevelt Island to where it splits off to North Arlington, northbound, and the downhill curve heading in the other direction are both equally treacherous.
Another road hazard that has caused numerous accidents but which is a permanent feature on another section of another road is a particular manhole cover that was installed improperly to begin with. But others become dangerous through improper maintenance or wear and tear/damage, etc. But the one I am talking about is on Lee highway in falls church, Virginia just before you get outside the beltway. It's after a long flat stretch of road just as you apex a right hand curve and begin to go up a hill. The manhole cover is perfectly lined up to be in the path of almost every tire of every vehicle in the right lane. The lip and rim of the cover is a good three or four inches above the road surface and the cover itself is recessed into the rim by about another four inches, creating a solid and unforgiving permanent pothole.
Many of the accidents that are caused by this involve serious injuries and time consuming extractions. But the manhole cover appears to be well maintained as if VDOT is well aware of this pothole and actively maintains it. Ironically it's less than a quarter mile from a major VDOT equipment yard and state police refueling station.
NoVA resident here. I think you're talking about RT 29 (Lee Hwy) near the I-495 Express Lane exit, but before the Shreve RD intersection/light? 🤔
Could you do a video about speed cameras next? Like you did for red-light cameras? Why are speed cameras virtually non-existent in the US but other countries use them a lot?
My state uses them often in residential or school zones (Maryland)
When I lived in Orlando Florida about 7 years ago we had about 30 red light cameras all over the city.
D.C. has speed cameras. They even have one installed in a white van and another in a marked MPD cruiser which they can move around and park in problem areas.
The reason they aren't used as frequently in America is because of our freedumbs. In other countries they treat speeding as a thing that needs to be mitigated, while in America everything is about power, control and punishment. A speed camera cannot impose points on a driver's record nor can a camera ticket jeopardize your right to operate a motor vehicle. In america, a simple fine isn't sufficient. It has to be punishing enough to cause harm. You need to be afraid of the law.
I'm not kidding. One of the biggest objections to speed cameras is that it is legally challenging to impose points or suspend a driver's license for failing to pay or for extreme violations. Another objection is that cops use minor traffic infractions in order to troll for other crimes and as pretexts to single out "suspicious" people so they can run a background check on them to make sure they don't have any outstanding warrants or are otherwise socially undesirable.
Here in Chicago there are a lot
He has videos about it
O boy, time for another classic 3am rob video. Thanks for the night material :D
These big horizontal poles hanging over the road are so strange to me, where I come from lights are mostly mounted on vertical poles, and if they need lights over a wider road they’ll usually have the road split up into multiple sections with traffic islands between the lanes with more vertical poles mounted in the islands. As a bonus, they also act like refuge islands for jaywalkers like me.
It's just common sense to do it that way, ti's why most the world does
That's also a road hazard. It's something to run into.
The city I live in is prone to serious gales from time to time (not to mention wind tunnel effects between buildings sometimes). Poles are mostly vertical. Usually we get by with vertical lights on both the near and far corners of the intersection, with none overhead at all. Sometimes the pole will come up, then out at a 45 degree angle for a bit, then horizontal only very briefly to mount the light (this will also usually be the same pole that has the regular 'side of the road' pole mounted at the usual hight imediately before the first bend, because these are single poles, not a horizontal bit attached to vertical bit.). Big horizontal arms like those shown here are super rare (and mostly old)
Though it's noteworthy that we do Not do the whole 'a set of lights for each lane, over that lane' thing, meaning the arm doesn't need to reach the Whole Way accross the street. Instead, one set of lights serves for all lanes, with additional 'arrow' lights giving instructions that override the main ones if you're turning in the indicated direction. If you want to close a single lane of the road, you stick big orrange signs and traffic cones on it indicating that that lane is closed. The lane markings indicate which directions you are allowed to exit the intersection in frome that lane. Which does you no good if you're stuck in rush hour traffic at an intersection you're unfamiliar with, though there are consistent patterns (left most lane will let you turn left, right most lane will let you turn right, if there's a third lane in the middle it probably won't let you turn at all unless you're turning onto a multi-lane road, that sort of thing. the confusing part is when there's two lanes, and one of them is turning only and the other is straight through and turn... you can't always tell which one will let you go straight through... though it's generally the case that it's the one with less cars cued up waiting to turn.)
@@paulwoodman5131 Yeah, but if you might be stopping at the light you shouldn’t be going that fast anyway…
@@paulwoodman5131 You mean the stationary object is so much scarier than the oncoming traffic you'd be running into head on if you were going that way to begin with?
Love this video! Civil engineer here and I've been working on a design for an overhead cantilever sign structure and this video helped me understand galloping wind loads a lot more! Thank you! I wonder if you'd be interested in covering all the different types of overhead sign structures and why there are so many different variations of them.
That’s great!
No wonder these structures keep breaking when the civil engineers are learning from TH-cam! 😂
@samwalker2367 haha, I guess what I'm trying to say is the design manual for sign structures does a horrible job explaining galloping wind loads and a visual representation helped me see what it does
imagine living on this street and a stranger builds a traffic signal and king kong playing with it🤣 good video as always
There _were_ a couple of random people watching the filming from the background of the shot in a few scenes, hah
Love the humor! This isn’t a slow clap. It’s just well dampened.
Those spirals you sometimes see at the top of tall chimneys are there to reduce vortex shedding. At the scale we're talking here, I wonder whether you could "just" wrap some thickish rubber insulation strip around the pole in a similar fashion.
I've noticed a bunch of moveable signs that have large circles cut out along the outside edge. I assumed that the purpose is to reduce the surface area that wind can exert twisting and/or tipping forces on.
In my other comment, I pointed out these were also present on older car aerials - so clearly this works on a small scale, too. I can only assume that this design was considered but not found to be effective.
I just discovered this channel. I am a civil (mostly structural) engineer, but have always been fascinated with traffic and roadway engineering. I've learned a lot of new concepts through this channel. Thanks, Rob!
I had no idea that 60-foot or 90-foot-long stoplights existed. That's simply terrifying. If a bird sat on one end, the leverage alone would put enormous loads on the structure. In my hometown, we often strung stoplights on cables suspended over wide roadways. This weighed less, and had the added advantage that because the stoplights themselves were only hung beneath the cable, they could simply swing out of the way of the wind. Of course, there was plenty of bouncing up and down, too, but it was less terrifying seeing a cable bounce than a stiff metal arm. However, they are now being replaced with more traditional stiff stoplights.
I was wondering what those poles were. Just got new lights at an intersection here in Seattle (not tornado alley) and they have those dampers. But of course had no idea that what they were. Now I know. Woot!
I have watched a load of these videos so far and I still don't know why I love them so much... I think the answer might be... Rob. What a guy!
I always love the humor and passion you put into every video!
You could see in his expression that Carl from Valmont clearly loves his job - even as much as Road Guy Rob!
Melbourne, Australia had some large signs fail on a freeway in the last few years. (Thankfully no one was hurt) Fatigue/wind was likely a factor, but poor welding was the main cause.
10:41 is down the street from my house
never in a million years i'd see that on rob's channel. and i've taken that exit many many times, i've never noticed the sign mounted that way. as always thanks for the content rob!
Your videos are next level, love them so much!
Awesome video as usual! I Love these! Always was fascinated with traffic signal set up’s! I constructed a half scale span wire set up with two real signals in my back yard!
I love this channel :) Thank you Rob :)
Right at the end of your video, I went for the like button but realized I had already clicked it.. You're that good, Rob. Thank you for the entertainment :)
I would love to hear more about the kind that are just stoplights attached to a cable. I've seen those "gallop" in the wind and it honestly is more scary than when the poles do it.
I've noticed that in some places, like North Carolina where I grew up, most of the traffic lights are simply hung from cables. In other places, like California where I live now, they're pretty much all mounted on poles like you show in this video. I have always wondered why some states use cables while others use poles.
Wow this is amazing!!! Shout out to the guy who created this!!! This can make a big difference!
The vid was definitely worth the wait Rob, keep up the good vids we love it
Thank you
Fantastic video, Rob!
I've wondered what those things are for! Terrific presentation. Thanks
Wow. I've lived in Vegas and have seen those flat signs on different places and had no idea why. Thanks for answering that
This was such a great video!! Thank you for educating us, Rob! :)
Thank you!
A very simple solution to hinder fatigue on those poles, the vertical pole, which holds the horizontal one extends higher up and you span a cable from the farthest extended end to the tip of the vertical pole. In that way you take quite some stress away from the horizontal pole and fatigue should hit less hard
Been enjoying your videos, just want to say thanks!
Thank you very much, @ezterry! I appreciate your kind words.
Production quality remains unmatched!
Thank you!
10:50 I never realized that’s what those were for! I thought it was so if they fell they wouldn’t break 😂
"Not cheap" at $6k? FOR FOUR?!?! Are you kidding me? That's dirt cheap in road infrastructure spending.
One of the best channels ever 😎
great and informative as always Rob!
Thank you!
About the part at 4:30, Canada has found a better solution for signal placements, where some of the left turn arrows are placed in the middle, concrete median of the roads.
Yeah I see an awful lack of refuge islands/medians, adding them would also make crossing the street a lot safer for pedestrians.
No mention of span wire and/or vertically mounted signals? Both are more common and work fairly well here in the eastern US.
vertically mounted..?
The span wire ones have their own issues when it comes to wind, and the ones mounted on poles are less easy to interpret.
Finally, I get an answer how to pronounce Tooele! Will Road Guy Rob's miracles never cease??!?!
12:27 Now I'm wondering what the natural frequency of Big Bird is...
Great, Rob, thanks for another "COOL" (ha -- usually... the wind is, I mean!) video!
This is the first video of yours i have watched, and i was surprised as heck to see the intersections right by my house featured.
I loved the bit about how to pronouce Tooele lol. As a Utah native, I never thought about how weird it was spelled until someone said "tooly". I also like how "tooele" isn't pronounced "tooly," but "Thule" is.
I always enjoy all the stock photos in Lubbock, Texas. Rob must really love us, ha.
Interesting knowledge that I didn't know I needed
I was wondering what a vertical pole was doing on a new stoplight. Now I know! Thx Rob!
Great video and good interviews.
Thank you
3:25 This is actually a less-common design of mast arm in Minnesota. The far more common design has a second smaller arm under the main one, acting as a brace. That design reduces galloping by a lot, but wind can still move it laterally. I can't recall ever seeing a failure except in very strong winds
I agree that adding a brace will reduce galloping. So would using a lattice truss design. But $6000 for four pneumatic-magnetic dampers might be more cost effective.
@@pacificostudios is it actually more cost effective though?
@@minnesotaball9792 I think so. A long brace, plus installation is going to cost more than $1500, especially if the traffic signal mast arm is already installed and this is a retrofit job. Many factors will apply.
Thanks!
You're welcome!
Maybe we should just stop buidling roads so wide with intersections that take up so much sirface area that require us to re-engineer what should be simple things.
Vortex shedding is reduced / eliminated on an automobile antenna (old style, not shark fin) by wrapping it with wire in a deep spiral - this could be done with power or signal cables, or with dedicated plastic or metal shapes.
I've always thought about this!!! Great video!!
Thank you!
this really has the quality of golden age myth busters / TV on discovery. Something to put on and just learn something interesting and get yourself thinking.
Amazing and interesting video! Thank you for this! However, I live near a fair amount of farmland in central Arizona, every day the wind gusting over the fields causes the street lights to gallop. I've always told myself when stopped underneat them that it's fine. They are designed to do this... Thank you for bursting my security bubble!
The signs facing up should say "wrong way"
LOL 😂
How do you know they don't?
I appreciate you correctly saying “Damper” and not “Dampener” (even though that schematic says “Wind Gallop ‘Dampening’ System) as the latter means to lightly moisten 😅
I had to fact check that. The words are easy to mix up!
@@RoadGuyRob Yea, it’s interesting to me, I’ve become hyper aware of the word damper vs. dampener after I learned about dampers used on bikes. And as a Star Trek fan, I had to rewatch some clips of the crew saying jargon like “Inertial “Dampeners’” when in fact they should have said “Dampers” 😅
WOW. Great explanation as always
Thank you!
In Alberta Canada, the windy areas have the street lights inline to the arm across the road. The lights don’t hang down and it really helps.
Love your videos, one thing I will give PA credit for (at least around Pittsburgh) is that when they replace older stop lights they are going for thicker / stronger structures. Everything from thicker poles to something that looks like the one on Decatur Blvd that you showed in Nevada. I only see those on the Pa turnpike for the most part and are typically painted blue!
Solution: Narrower roads (safer for everyone) and center medians that allow pedestrians to cross halfway when safe to do so, but also lets you put a pole up in the middle too
In Greenville South Carolina a signal was shaking a lot and it was between I-85 and I-385 intersections (literally right beside both of them) and thank gosh it was on the side where there was no road (it was a 3 way signal) (signal is on woodruff rd)
Around the St. Louis area, IDOT and MODOT have been using interstate sign bridges for stop lights recently.
Last year in Las Vegas, the signals for westbound Flamingo Road at Fort Apache Road was brought down by a sudden wind storm. When replaced, the signal arm included the horizonal wind plates.
Great video Rob
Thank you!
This channel is great! Finally a channel about infrastructure for Americans about American infrastructure. There are too many people on youtube whose main "points" always devolve into Euro-centric wishful thinking about high speed rail and "bikeable" cities rather than tackling American infrastructure and more importantly, the American culture surrounding that infrastructure, as it is. Also love the production quality and presentation. Very much so like a TV show from the early 2000s I'd watch on Discovery channel or something.
The Tooele name reminds me of a time I was in Hawaii. Our guide told us a story about a surfing beach town. Apparently some mainlander thought the name was interesting and chatted to a local, asking if it was something like "Pi'epe Li'nei". The local turns around and goes, "that's Pipeline you idiot!"
I've seen this happening to lots of signs. I even saw one fall down right in front of me by the railroad crossing as I was hiking on the trail next to it. It was lucky that it fell just then because it fell into the lane in such a way that it would be nearly impossible for a driver to see, even one who was actually looking at the road and not their phone, and it would have definitely shredded someone's tires because of the way the metal sign was facing and how it was wedged again the curb of the median. It was a small sign though so I picked it up and moved it so that the entire thing was on the median and no one would pop their tire on it. I've seen signs blow off the pole too.
I've noticed these vertical pipes at the end poles, nice to know of their function.
in tampa bay the vast majority of major stoplights and highway signs are built like that huge nevada one. i always assumed it was for hurricanes, but good to know that it's just safer in general too
Not that it's universally applicable, but roundabouts eliminate the costs of traffic light maintenance long term. The first thing I would look at in solving traffic light galloping issues is whether eliminating the traffic light with a roundabout is practical.
I think it's crazy the way the light poles are designed now, in my city we have poles from the 60's that only hold up one or two lights and have the protected left on its own pole on the median. The new ones they're slowly being replaced with reach all the way to the center and hold 3+ lights, they sway violently with the wind and I'm sometimes amazed the bolts don't shear. They obviously weren't engineered to last very long unlike the originals
I've seen some places hold these up on both sides, either by being double the length or if there's a median strip, put the other pole in the middle. The example at 6:00 is the beefier sort but I think being held on both ends also help.
As a kid growing up in the Bay Area of California, I've seen several kinds of different traffic signal setups at many intersections. One that stood out to me was that California at one time was big at installing left turn signals using mast arms shaped like a "T" on the median. That made it possible to mount more than one signal on the mast. As a kid, I thought it was a cool thing to see. As an adult, it makes more sense. That kind of installation allowed for shorter mast arms while providing signal coverage for the intersection. That right there was one way to reduce galloping on the mast arm. For more windy locations, I wonder to myself why they don't adopt a similar practice. There is one drawback, though. Someone who isn't watching where they're going can crash into it and knock the signal down. With all that said, that's one way traffic engineers can reduce galloping on the mast arm.
They could also try to simply put very thick robe wrapped around the arm. More robust option is to weld metal strip that is wrapping around it. As you mentioned, this issue mostly comes from the vortex that has frequency and strength that depends on the wind (and post thickness). Now if you wrap something around the post arm, it's not round anymore! Of course strong wind can still bounce it around but the most important part is that fairly constant wind will not cause galloping. Let's say that you wrap around every 3 feet. This means that every 1,5 feet the extruding part will be on the opposite side of the arm and it sort of acts as a sail. Except the direction is the opposite every 1,5 feet. It will still resonate but instead of having one 20 feet arm resonating, you have lots of 3 feet peaces that resonate independently with much smaller amplitude. And what happens when resonance amplitude goes down? The resonance frequency goes up a lot!
I have no clue how this method is called but it exists and it is used in many applications. I've seen it mostly on industrial chimneys that are very tall, round and made out of fairly thin steel for their size. They love to sway back and forth and even worse, the wind can blow from any direction! Yet, it's enough that there is metal band that wraps around it a few times to change the resonance frequency way outside of what wind can do.
Traffic engineers call these “traffic signals”. “Traffic light” and “stoplight” are taboo terms.
But awesome research and great, precise information. I love your videos.
That’s why in the UK we have lights on vertical poles, if there is a dedicated turn light on the side that can turn, if overhead traffic lights are require we use a pole at each side of the road with a pole that connects to opposite side of the road, traffic lights aren’t very strong for the most part so if a car hits it then the light will be dented or collapse and need replacing, bigger poles/ piers are protected with a barrier so if a car or truck will be deflected away from that structure
engineering is so cool. Really wish stuff was like this was taught in school.
Growing up in Texas I was used to traffic signals hanging over the roadway. Washington DC mounts its stoplights on a single post to the right of the intersection. This makes the driver focus towards the corner instead of the road ahead.
As a side note, DC removes the stoplight posts during scheduled parades and 'expected' protests to prevent people climbing on them.
I remember seeing this happening years ago, but wasn't sure whether it was safe or not--luckily enough, it at least didn't fall down while I was in the area. I did wonder how it happened, but it's been a long time since I've seen it happening, so I haven't been thinking about it.
Where I live most traffic lights are on a cable strung between poles on each side of the street. They move some in wind but I've never seen one fall down and this must cheaper than using those big thick poles.
HAHA I love the Gorilla! We need more Gorillas in more videos everywhere!!! Also never thought about this issue! Fascinating that a stop sign galloping could cause so many issues.
Where I live, there's also galloping sign gantries on the highway. It can get a little dicey looking as the signs would move up and down several feet almost like two people swinging a skipping rope.
always good to see a video from rob
Here in the UK. 1. we just don't have intersections that large like Nevada's fat paperclip.
2. Where we do, there are islands built and lane separators so each direction of traffic has their own lanes and lights.
3. If vertical posts aren't possible we just span the lanes but again use an island to separate inbound and outbound lanes.
4. Crosswalks are Zebra Crossings
5. Stoplights are traffic lights
6. Amber indicators and filter lights would help with you road safety massively and not this weird right turn on red thing...