Wind? Please take warnings seeriously...

The problem with "wind warnings" is many [light] trucks drive in/through them without issue, then some get blown over where there was no posted "warnings" in effect [yet].

It's not the "winds" that get you in trouble, it's the random "gusts" that blows trucks over. Gust and higher winds can often be predicted in geographic areas where changes in area and road topography, and natural wind breaks (trees vs no trees) occurs. That said, there comes a point where the wind situation crosses the threshold from bad to intense. It is at that point, you may need to look for a place to stop, leaning heavily into the wind.

Today's air ride tractors and trailers only exacerbate the problem, even for heavier trucks.

 

[h=1]Semi Truck Blown Over By Wind ! ! ![/h]http://www.youtube.com/watch?v=0l0_Nj6GNe0


[h=1]Strong Winds Blowing Semi-Truck of Road!
http://www.youtube.com/watch?v=aQ4rbd0Zfwg[/h]

[h=1]Wind Flips over a Semi Truck, Fast and Furious
http://www.youtube.com/watch?v=QD2ZqKJ1oyM[/h]

 

Is that a spoon int he last one....He was probably eating while switching lanes and amplified the wind effect by jerking the wheel.

 

All three of those posted by the OP made the local 5 pm news.

My rule of thumb, when Wyo. says "NO LIGHT WEIGHT HIGH PROFILE VEHICLES, 65+ MPH GUSTS" or "ADVISE NO LIGHT WEIGHT VEHICLES"....I take my toys and go home.

I've had one blow over, me and Mother Nature have a mutual understanding, rain, snow, sleet, hail, dark of night, pestilence are all good. Wind however, that's another story. All it takes is one blow over or your trailer to try and pass you on the shoulder a couple of times and you learn not to mess with it.

 

If you've been driving long enough, you have had a butt clinching moment with a gust of wind, no pun intended.

 

All these drivers are in trouble if they were on I-80 in Wyoming. I-80 was closed to all high profile vehicles west of Cheyenne. Drivers who continued risked citations. I had to stop at the P. O. E. To buy a permit and was ordered to shut down at the next exit as all high profile vehicles were banned due to high winds. I was advised that in an accident my insurance would be invalid and that I would receive a citation even if I was not at fault because I was not supposed to be there. We were also advised that in an accident we would be required to pay for all cleanup cost even if we were not at fault.

Needless to say I shut down at the next exit. Thank goodness the Sapp brothers truck stop at exit 370 also has a motel. I would also add that the electronic signs on the east side of the state were advertising the road closures for high profile vehicles west of Cheyenne.

These drivers may be in more trouble than just a citation or losing their jobs. If what I was told is true then they are also responsible for all cleanup cost & there is no insurance.

The moral of the story is "when the signs, the cops or conditions tell you to stop, STOP!"

 

Truck drivers have access to a plethora of information as well. They have the NWS, internet, cb radio, DOT hotlines, and commercial weather providers. The only thing they don't have is...well...flightwatch lol. Also, I have yet to work for a company that has threatened to fire me because I felt unsafe. If that's the case, then I don't need to drive for said company anyways...and as insurance, CSA and BASIC scores now rule the scene, companies are starting to realize that, when a driver gets into a predicament, it can really screw up the company as well. So in turn, they are listening to their drivers more when they say that they don't feel safe doing something. Trucking companies rule by fear because we live in the age of tort law. Only in our industry can you have another person intentionally do something to you to cause you to get into an accident and it STILL be your fault. The only way to get companies to loosen their grip is by getting the federal government to loosen their regulations...and that's never gonna happen.

 

I have pulled it over for the day many times on I-80 in WY for high wind conditions when I felt it was unsafe to drive.
Swift has never given me any problem about it.

 

Should have had that prostar steering shaft recall done...

 

It is way more complex than that for a moving truck! The angle of incidence changes based on the ratio of truck speed versus wind speed, (as well as wind direction which would effect the Cd as well as A. p can be removed unless we need an absolute value, in this discussion we're more concerned with where the maximum is rather than what that value is. The formula you give doesn't properly account for the fact that we are dealing in vectors having magnitude and direction.

For example, a truck in a very strong quartering tailwind (let's use 60mph @135*) would have a lower wind loading at 60 mph than at 45 mph. The resulting wind is 46 mph @ 67 degrees driving 60mph vs 42 mph @ 87 degrees driving 45 mph. And since both A and Cd are greatest with a 90 degree wind incidence, slowing is actually the wrong thing to do at that particular windspeed and direction! Even dropping to 30 mph leaves the wind 44 mph @ 106 degrees, a higher loading than at 60mph. As the wind speed becomes greater, those angles close up and move further towards the rear of the truck, being 87 and 101 degrees @ 60 and 45 mph truck speed with an 80 mph quartering tailwind, and now slowing has some benefit.

A Cd of 2?!? Plus, I didn't see any formulas to know if he accounted the effect of the truck's motion on incidence angle, but surely it did.