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I recently drove on a rural road at night during a wind storm. There was a tree down on the road. So I put my hazard lights on to alert other drivers, and I was about to call the municipality, but workers showed up and cleared the tree before I could make the call.

That situation worked out fine, but in the future, I'd like to have a warning device that I could leave on-site if waiting isn't an option, such as emergency triangles.

https://www.princessauto.com/en/warning-triangles/category/410-005-005-095

enter image description here

It occurred to me that triangles might just blow away in the wind during a wind storm. Is that a common problem? Is there a different kind of device that would be more suitable?

For example, a device that I could nail into the gravel shoulder to anchor it from the wind.

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  • The wire legs of the left sort can sometimes be jammed into the ground, if there's soil or gravel in the right place (or gravel can be kicked over them). The triangle should be angled towards oncoming traffic of course, but it's retro-reflective so this doesn't need to be perfect
    – Chris H
    Commented Jun 10 at 9:45
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    If you plan on leaving it, perhaps nail it to the tree. Commented Jun 10 at 12:43
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    @WeatherVane when used for vehicle breakdowns the triangle should be some distance (45m - UK Highway code) before the hazard (hitting the triangle is no big deal if spotted too late compared to hitting a stranded car, plus you can site it for a better line of sight). I see no reason not to apply the same rule here, so even if you have a hammer and nails in your car (I don't but I do have lots of strong tape and some paracord, which would serve the same purpose) this is unlikely to be the most helpful approach
    – Chris H
    Commented Jun 10 at 13:10
  • @Chris even if not placed in advance, the reflective triangle fixed to the hazard may provide more warning than nothing. In the third type pictured, one end of a tree branch could be passed through the triangle to weight it. The others look too flimsy to withstand being crushed. Another problem is, does the sign itself become a hazard? Commented Jun 10 at 13:18
  • Better than nothing. But it shouldn't be a hazard itself That's a benefit of it being light. Unless you do something dumb like positioning it so people would try to drive round it and into a ditch. I'd be loosely guided by the highway code rather than measuring 45m, and go for just before a bend if the tree is after it. I used mine recently after limping the van onto the sliproad of the A11, where there's a gutter wide enough to act like a hard shoulder for van or triangle. I put it just before a bush as the sliproad left the dual carriageway,. It looked just like the first one
    – Chris H
    Commented Jun 10 at 14:09

5 Answers 5

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It will depend on the weight of the triangle but in a storm that blows trees down there is not much that will stay where you put it.

I have seen roadworkers triangles weighted down by sandbags, and that is likely the model that is right most in your picture.

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    In my own experience putting down a triangle on the shoulder of the motorway, the poor little thing was knocked over by the wind of the first truck passing in the close lane... needless to say, I wouldn't expect it to stay upright long in a storm. So yes, they need weighing down. Desperately. Commented Jun 10 at 17:11
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In these warning triangles, there is a compromise to be made between bulk, weight and the ability to stay put in strong winds. As for all emergency equipment, there is a tendency to make things small and light with certain drawbacks in rare conditions. If they are about to be blown away, you can just weigh them down. Maybe there are some bigger stones nearby, or a part of a branch you can use. Maybe you have something heavy in your car (tools, box of beer, etc.)

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  • I don't know many drivers who randomly have a box of beer in their trunk they're willing to leave behind to warn other drivers, especially in a windy storm.
    – Nzall
    Commented Jun 12 at 19:24
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There is a comprehensive European norm ECE R27 for warning triangles. Among many other things, it specifies wind resilience (must not be turned, shifted or pushed over). A revision from 1995 contains the following specifications in section 10, "Test of stability against wind":

  • The air stream shall reach a dynamic pressure of 180 Pa;
  • The advance warning triangle shall be subjected for 3 minutes to this open air stream
  • The advance warning triangle shall neither overturn nor shift.
  • The retro-reflecting triangular part of the device shall not rotate through more than 10° round a horizontal axis or a vertical axis from its initial position.

According to this calculator, 180 Pa may correspond to a wind of 17 m/s or 61 km/h or 38 mph or, perhaps not coincidentally, the upper limit of Beaufort number 7, "High Wind".

In other words, in winds likely to topple over trees, you'd better put some weights on the base. Don't forget to put the triangle at a considerable distance for maximum effect; at 65 mph or, roughly, 100 km/h, a car travels almost 27 meters or roughly 90 feet per second. The recommendations are to have it 100 meters or 320 feet back from the accident on highways, even more on freeways.

As an unrelated note, independently of trees, wind and all else: Get people out of the car and behind the guard railing. If possible move your car aside or past an accident as well, for the reason shown in this arbitrary example video.

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  • For our scenario, wind gusts are relevant, and a gusting wind of Bft 7 isn't really much, and certainly not a storm. It's called a storm if the average wind speed reaches Bft 8 (with gusts at 9 or 10). So while your answer is good, it proves that the triangles will likely not hold in a real storm.
    – PMF
    Commented Jun 11 at 14:18
  • @PMF I agree with everything you say, except the "while" ;-). Perhaps I'd also take issue with your conclusion "that it can sustain 7 Bft proves it will likely not hold in a real storm" ;-). It may or may not hold (I think it won't but that's simply me having had one in my hands). Commented Jun 11 at 14:23
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It would seem that simply moving the tree branch might be more effective. Even for a large branch, a rope connected to a stable attachment point on your car can certainly move any branch. If the ground next to the road is not safe to drive on. Then make the rope into a V, putting the point of the V at a tree trunk or other vertical, stable point off the road. Then attach one end to the car, the other end to the downed tree. This effectively creates something similar to a pulley, directing the downed branch towards the stable tree instead of towards the car.

However, in this exact situation and to more directly answer your question, at night an LED flare would be more effective than a road triangle. A flare will have less surface exposed to the wind and higher natural weight, so is less likely to blow. Plus, it inherently provides it's own light so is more visible at night.

These LED flares cost a little but not too much more per flare. It seems that for various reasons like dead batteries, etc. truckers are required to have the triangle style flares in the truck, but can use the LED flares. See more details
Variety of electric flares and hazard triangles
Pair of LED roadside flares As of June 2024, they list as a pair for $24 in the U.S.A.

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  • A diagram would be much simpler than the long written description of how to attach the ropes. If anyone has the time to create and edit a diagram into this answer, that would be wonderful.
    – nickalh
    Commented Jun 11 at 10:52
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    A branch, maybe, but the question says "a tree down", and a tree could be several tonnes as well as caught (or at risk of getting caught) on other trees. Generally when I've seen trees down I wouldn't be confident of moving them with my van let alone a small car - and while I carry a tow rope it's not really suitable for this job. Luckily I've always been cycling and able to get over or round
    – Chris H
    Commented Jun 11 at 10:53
  • I'd try for even a tree unless it was a particularly huge tree and/or sufficient wind makes it dangerous to even walk on the road. However, I may take a few more risks than most people. Example- I have successfully helped push a stuck car using my arms and legs, not my car, off the middle of an interstate highway without any injuries. He had slowed traffic down to a couple of miles an hour. I also keep safety reflective vests in my trunk to help those who are stuck and walk on the shoulder side of any parked cars away from traffic.
    – nickalh
    Commented Jun 11 at 13:16
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    I'd push vehicles clear in slow or stationary traffic, no problem, but that's a different issue to an improvised attempt to move a tree, that could cause further problems. Small and isolated, maybe, but here the trees that blow over tend to be the tall ones
    – Chris H
    Commented Jun 11 at 13:50
  • If you are going to attempt to move the debris yourself, you really don't want your warning triangle to disappear whilst you're exposed in a live lane! So it's really not an either/or situation. Commented Jun 13 at 13:34
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If using satnav you can post the hazard details onto the maps.
Such as

enter image description here

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    That only works for people who are using the same satnav system as you are, and only if you are sufficiently non-rural to have an internet connection.
    – Mark
    Commented Jun 10 at 23:41

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