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!
@@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.
A majority of traffic lights in Minnesota, unlike the one shown in this video, are braced using a second smaller pole on the underside. Its always seemed like such a simple solution and I've always wondered why I only ever see it commonly in Minnesota.
There is an entire field of study dedicated to the interactions between the aerodynamic loads and the resulting structural deformations: it's called aeroelasticity. 95% of all the “aeroelasticians” of this world work in aerospace (from research lab at universities to companies like Airbus and Boeing). Of course similar interactions happen to many other man made objects such as bridges (see the Tacoma bridge disaster), wind turbines, solar panels, sailing hydrofoils and of course traffic signals. Thanks for covering this topic!
If you want to learn the resonance of a cantilever (even with stuff on it), you just go up and twang it and measure it. Then you go back to the shop cut a spring to the right length to make a tuned dampener and put it in a cylinder with a cannon ball on top of it to make a tuned dampener, then you go back and put it on the arm. Just three components and the cost of going back to bolt it on.
After all this years, engineers still didnt learn it has nothing to do with the lights, just the tube. The turbulence it creates, you can quit the lights an the tube will vibrate the same. Some spiral plates or a mass dumper can solve it. Maybe even using the lights structure as mass on a springy suspended structure can solve it.
Ok, but what about... making it an arch? I.e. putting another pole on the other side of the road and having the horizontal pole connect with both. What is the difference in up-front cost + maintenance?
why don't they add a short, 3ft-long diagonal arm into the mix, but only install it, AFTER pre-stressing the horizontal arm by lifting it upward with a machine as much as it could go (maybe one or two feet higher on the end of it. NOW, install a short diagonal arm that connects the horizontal and vertical bars. Release the machine that was pre-stressing the horizontal bar, and WAH-LAH, you have a STIFF street light system!
The cable system is dumb because u have to keep tightening it. tighten it with a cable, THEN install a short diagonal arm connecting the two arms!!!!! damnit!!!! lol
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.
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.
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!
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.
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.
@@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 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.
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.
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.
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...
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….
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).
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 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
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.
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.
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)
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?
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 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.
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 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
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 just find it weird that the USA gives ever lane its own set of lights. Just... why? all the traffic going in the same direction will have the same light at the same time, after all. Where I live there's a main light for All traffic (repeated on ever corner and Sometimes a single overhead panel), and then secondary arrow lights May be present on that pannel as needed for each direction that traffic could be turning in. If you're in a lane that's turning in the indicated direction, the instruction given by the relevant arrow overrides the main light. It's very rare this amounts to more than two extra lights (because arrow lights are Only present when part of the cycle involves giving turning traffic Different instructions from everything else). Though in Theory a full array could amount to five columns (left most turning, less left turning, straight through/all, less right turning, right most turning, with a full red-amber-green set for each) or more (why does your intersection have more 6+ possible exits? WHY?! ), I'm fairly sure there's no intersection that actually does this.
Beat me to it. Seriously, that stroad he showed off in Vegas... 14 lanes of traffic! Did nobody stop to consider the absurdity of what they were doing, and that maybe there's a better solution to traffic than just throwing down more asphalt?
It's not just the insane width, it's the insistence that all that surface has to be devoted to Car alone. Can't have those signs and lights supported on both sides, because that would mean some place in the road where you can't make a U-turn! Obviously that Freedom must be prioritized over not having traffic lights fall on you.
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!
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.
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.
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 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?
Aye Rob, I watched your last video on traffic signals and I gotta question for ya, what’s your problem with span wire traffic signals? Besides the fact that span wire signals are more fragile. I live in Virginia and we have a mix of both mast arm and span wire signals and I think they both look pretty cool. I know California and Nevada don’t.
When I spoke with Florida they mentioned two problems: 1. Wear on the wires. As the signal head floats around in the breeze, the wire connection bent repeatedly. Sometimes it breaks and the signal loses power. Or worse, the head falls off entirely. 2. Aesthetics. Mast arms look nicer. Cities figure it's worth the extra money.
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.
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.
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.
@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
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.
It's not hard science to figure out the resonance frequency of a pole with lights on it. It's hard to predict it ahead of time, but, out in the real world it's dead simple. You grab the end, lift it a few inches, and drop it. It'll bob up and down like a sideways pendulum. You just measure it and now you know the frequency. Or, they make devices that can measure this to the millionth of a inch (strain gauges), you could put it anywhere on the post and have a reading within 2 seconds. Then you'd just tune the damper to that frequency. That said, the electromagnetic/pneumatic ones are universal and a better solution that tuning anyways.
I was thinking the same thing. You don't need to put the structure in a wind tunnel to find the natural frequency, since all that depends on, is the mass, distribution of mass, and stiffness of the pole. All that can be tested at ordinary wind speeds. Just put a strain gauge setup on the pole end, and apply a sample impulse load to the far end.
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 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.
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
Sounds like an engeering ream that got a wiff of public money They probably have little incentive to keep costs down No reason why thw state couldn't reversw engeer these and make them themselves
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 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.
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.
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 😅
@@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” 😅
Most of your problem is because the roads are way too wide. I currently live in a town with only one stop light intersection but even in other cities I have been too I have not seen stoplights over the road because there simply aren't that many lanes on any roads with stoplights in most countries. Its an American phenomenon mostly.
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.
I've seen this done in a few places. As long as this slits are done so they don't pass light to the drivers that are facing the signal it would have to help.
Heads up! That common demonstration for how airplanes generate lift is incorrect! The wind doesn’t have to meet up at the other end. Don’t believe me? Then try to figure out how planes would fly upside down.
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.
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!
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.
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!"
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)
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.
Makes me think we need to work on our roads- maybe make them with less lanes, and have have a 2-3 short, vertical lights on each side of intersections instead. Would probably also make people focus more on the road and their surroundings this way too
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.
if you want to know what other countries done to solve this? they used multiple poles... the amount of money that went into R&D could have been spent in better places... USA just likes to waste money. Australia has 4 poles 2 closest to the line on the left and right side and 2 on the far side on the left and right with minimal masts.
Hi honey, did you have fun at the park today? *blank stares Was a giant monkey pushing a grown traffic guy on the swings again? *existential crisis intensifies
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!
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
How come most other country don't need this huge poles for the traffic lights, where i live in sweden we don't have them, even if a road have many lanes one stop light on the side of the road works fine.
No mention of fitting helixes to the structure? Is that too expensive or technical to do as it's a non moving part that would require little to no maintenance.
I want to see them start using the LED lit pole for the traffic lights, that have the whole pole covered in red and green LEDs. Maybe if the pole lit up too, they wouldn't need such a long one to get all the way across multiple lanes.
We're not getting that because 4% of humanity is (at least partially) colorblind. Maybe it could work if someone 150 years ago decided blue should mean go.
Or ... and hear me out on this radical idea ... don't build roads that are big enough to land the space shuttle on and then put traffic signals on them 🤔
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.
@@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.
That's genius. The faster the mass moves in the tube the more electricity is produced so the stronger the magnetic eddy current is and the greater the resistance to movement and the greater the dampening. You have a passive harmonic damper. Obviously a tuned dampener would have the exact frequency but this is close enough.
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.
...or just stop making roads the size of a highway, and you won't have to have arm masts that span 8 lanes out and are longer horizontally than their support poles are vertically
Ever since seeing these massive single support masts being installed everywhere around the country, I have been wondering about the logic behind them. Clearly there is none, a poorly thought out idea. Why not use gantries instead? Even better, just get rid of traffic lights all together! Use more roundabouts and also Americans need to come to grips with idea of priority roads! In my county they are adding traffic lights and stop signs as if they were candy.......what''s up with that? This runs completely contrary to the idea of reducing energy consumption.......
Or do what seemingly litterally everyone else does: Just use one set of lights for all lanes that are doing the same thing! Put a pole on each side of the road/on an island in the middle so all vehicles can see them and you're golden. Most of the middle sets are redundant, and thus so is the arm.
Why do highway engineers place so many huge signs over travel lanes. Some are obvious like "these lanes keep going V V while those lanes veer off > > ". But why do giant one-sign notices need to be dangled over the traffic. "Next exit one mile" Why not just stand it on a post off to the side. They'd use way less steel and foundation needed to reduce the risk of part/whole of if dropping into traffic.
That _is_ done where there's enough space to the side, and where the view won't be blocked too much by traffic. Also, in my experience, highway overhead sign gantries are usually _much_ bigger and beefier than traffic light assemblies. The horizontal parts tend to be trusses that are much taller -- and more resistant to bending up and down -- than a pole.
Hi, @PsRohrbaugh! When I spoke to engineers at Florida DOT, they mentioned the wear a dangling signal head has on the electrical wires inside the cable. We going back and forth over and over again in the wind can eventually cause the connection to break, making the signal lose power.
