Infamous 'can opener' bridge in Durham, NC, is finally being 'fixed'... 4

[LittleInch]

It's fun watching that. One issue clearly is that the traffic lights on the bridge seem to bear no relation to the over height warning. Sometimes they're green, sometimes they're red.

The FAQ section of the website says there are many warnings and signs before the bridge but even so....





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[HorsieJuice]

This saddens me a bit. My wife and her siblings all did their undergrad degrees in NC, so a couple years ago we all went down for homecoming and to visit her brothers at Duke. They're a big sports family and *really* into school spirit, some of which they were hoping would rub off on me during this glorious weekend in the south. Well, I don't give two hoots about my own alma mater, much less somebody else's. They weren't too amused when the only thing I got excited about all weekend was seeing "that bridge from the internet."

 

[IRstuff]

LI,
The traffic light is the traffic light for the intersection. The warning sign starts blinking when the bridge detects an overheight truck, but unless they know that the blinking is because of them, they'll see it only as a general warning and not applicable to them.

Of course, there seems to be a very high incidence of red-light running, so those people will obviously ignore the overheight warning, just because they're running the light anyway.

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[3DDave]

I think the rental trucks are typically not from the area.

The light turns red on the initial detection, turning green to allow the over-height vehicle to turn at the intersection; if it stayed red then no traffic could move. There should be at least one red cycle before an over-height vehicle enters the intersection.

On Google maps one can take a tour down that road. There are many signs leading to the bridge; they seem to fail for those who forget they have a truck or trailer behind their seat.

Some think the trestle shakes - there is a walkway on the side of it that cantilevers and the railing and walkway do shake; I expect the bridge does not as it does not deflect when a locomotive rolls over it.

 

[IRstuff]

The red light is strictly the intersection traffic light and has nothing to do with the trucks. The humongous blinking letter sign is what's supposed to warn the trucks. I've only seen one video from 2019 where the sign didn't blink. Note that most of the red lights you see are where the trucks and other traffic are running that red light.

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[3DDave]

The red light was attached to the over-height sensor to stop traffic when the initial over-height item is detected and give drivers the option to think. I assume most do and make the turn. It has to turn green sometime.

"The signage is good, and the vast majority of truck drivers notice the problem and avoid the bridge. Large signs alert driver to the low clearance several blocks before the bridge. Half a block before the trestle, a sensor detects overheight vehicles and triggers an LED blackout warning sign that was installed in May 2016. That same sensor also triggers a red-light phase at the traffic light directly in front of the trestle (installed in March 2016), so the driver has 50 seconds to read the warning sign next to the red traffic light and consider their next move."

http://11foot8.com/faq/

 

[JohnRBaker]

I guess it's possible that the 'locals' know that when the warning sign is flashing AND the red-lights are ON, that the cross street's light are also red and so they just take advantage of the situation and drive through the intersection knowing that it's 'safe'. If the city wanted to make a little extra cash they would assign some patrol cars there to not only ticket the drivers who ignore the warning signs and hit the bridge, but also all of those other drivers who blow-off the red-light thinking that it does not apply to them. After all, a red-light is a red-light, and when it comes to traffic laws, it has to mean the same thing to everyone. And if they wanted to get really bitchy, the city could install a red-light-cam and automate the entire process.

BTW, even if they do manage to successfully raise the railroad bridge eight inches, they will still need to keep all of the signs and warning systems in place, only changing the clearance warning from 11'-8" to 12'-4". And there will still be crashes, albeit less frequent (they hope), than now as there are still a lot of trucks out there with loads taller than 12'-4".

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[IRstuff]

Look at this video; you can clearly see the sign blinking, but the traffic light is green.

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[XR250]

I was driving a few hundred feet behind a camper going under this bridge. The lights were flashing and he/she did not seem to notice. Watched his A/C unit get ripped off the top.

 

[IRstuff]

Signage is often a big problem, particularly something like this. When do you notice the sign is blinking; was it blinking all the time? "You talking to me?"

A cool high tech solution might be to have a steerable high-intensity light that shines directly at the truck driver, "Yes, you, you numbskull; your truck is too tall for the bridge!" Or, maybe, it just flashes, "Turn away from this light!" However, I saw one video, out of about 10 viewed today, where the sign didn't flash, possibly because the truck was JUST BARELY over the limit.

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[JohnRBaker]

And the local authorities also have to be careful to not make the height detector too 'conservative'. After all, if it can be shown that the detector is forcing the rerouting of commercial vehicles unnecessarily, this could lead to official complaints if not actual legal challenges. And again, all of this talk about 'fixing' the bridge, will only mitigate but not eliminate the problem.

BTW, does anyone know what the minimum overpass clearance is on say the interstate system? What about municipal streets? I realize that if there are such standards and or even regulations, that this particular structure would have been grandfathered years ago, which brings up a question for the people out there might actually know. How much 'tinkering' with this bridge can they get away with before they reach a point where they are forced to simply replace it altogether? It's like where I live here in SoCal, in a desert environment, where wild fires are frequent. When our residential development was built back in the mid-to-late 70's, they were still allowing wood shake roofs. Now every 5th house or so had clay tile roofs (ours is one of those) but the rest were wood. Since then the laws have changed and wood shakes are no longer allowed, but they couldn't go in and force home owners with wood roofs to replace them. However, they did pass an ordinance that if a home owner attempts to replace more than a certain percentage of his wood roof with new wood shakes, then he must replace all of it with some sort of fireproof material. This protected people who needed to only make minor repairs while also protecting the community from people who replaced 90% of their wood roof with new wood shakes while saying they were only doing a minor repair. I'm not sure what this minimum percentage is as it was never going to be an issue with us. Since we moved into this neighborhood 32 years ago, virtually all of the wood roofs have been replaced with fireproof materials, but there are still a few holdouts who have gamed the system by only replacing small sections of their roof every couple of years. A few of them have probably replaced their entire roof more than once over already, but they're resisting out of principle, I guess. I suspect that if they had just bitten the bullet the first time there was any significant work done that they would saved money in the long run, to say nothing about getting a discount on their homeowner's fire insurance. And for the record, within our development, which this story was related to, there are 134 homes, and as I said, there's probably no more than five left with wood roofs.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
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[3DDave]

This overpass is about 100 years old. AFAIK it predates the US interstate system.

 

[3DDave]

The red light is not a height control. It is not held on as long as any over-height truck is anywhere in the area. The FAQ from the guy who lives there tells that. It triggers as an over-height vehicle is detected, but it's got to turn green sometime or it will just block the entire street.

 

[bones206]

Would it be an effective deterrent to install those hanging overhead clearance bars things that are used in parking garages? They could put one at each of the 3 sides of the intersection, so a truck would get clunked away from the bridge and hopefully stop at that point.

Edit: Maybe not at all three sides since innocent trucks traveling parallel to the bridge would be getting bonked unnecessarily (good point by 3DDave), but having one on the bridge side of the intersection would probably help a little bit at least.

 

[3DDave]

Those clanging banging noise making things that would irritate the neighborhood for blocks around for the 99.99% of delivery trucks that don't head for the bridge? Making the sound of a good bashing all the time instead of just when someone deserves it? Sure. Punish all the people.

 

[bones206]

Didn’t realize they were a noise issue. I was imagining something like this:

 

[charliealphabravo]

My grandfather always said that you can't make something idiot proof

The signage is an interesting example of a doomed attempt to accomplish that. Arrows related to the hazard point in literally every direction. I wonder how many hours have been spent in staff and council meetings trying to decide which way the arrows should point

 

[3DDave]

It better make a lot of noise to get through to drivers that have ignored a bunch of signs and -exactly- that same bar across the roadway that they keep hitting at the bridge.

This bridge has been investigated for nearly 80 years.

As if in 80 years no one living there was smart enough to realize a simple fix would work.

This signage seems clear -

 

[IRstuff]

But, that sign can be easily obscured by a truck in the RH lane doing the correct thing, while the victim (?) blithely carries on in the left lane. It also depends on the driver actually paying attention and assumes that the driver actually remembers the height of the truck they're driving, which seems particularly difficult for a rental truck. Half the time, I can't remember the color of my rental car the next morning, and something the rental counter person told me 3 days ago, like the height of the truck, might be long gone.

I certainly wonder whether some sort of hanging sign at the height limit might have been more effective. I would have thought that a sign that said, "Turn away from this overpass if you hit this sign" might trigger some sort of survival instinct.

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[3DDave]

At the head of the street are a pair of 11'8" warning signs, one on each side. The limit signs are duplicated at the bridge.

The correct answer is - if your truck is over 11'8" don't go across the intersection.

Rental trucks usually have the height placard on the dash board in front of the driver and on the side of the box where it is properly readable in the side mirror.

1000 trucks slamming into a noise producing obstacle and doing some damage to the trucks as well is a poor way to stop the 1 from hitting the barrier.

This isn't an office park or a parking structure. It sees truck traffic all the time. I'm sure that 80 years of deliberation came to the right conclusions that preventing non-injury accidents is primarily the responsibility of the drivers and that providing multiple warning signs, flashing warning signs, and a striped beam that's been damaged, should be enough.

If the driver isn't paying attention to a certain collision situation they need to not drive anymore.