Originally published at: Optical illusion has drivers concerned that new bridge support is leaning dangerously | Boing Boing
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I wonder if painting it using a trompe l’oeil technique would work. 
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Not sure what’s up with those drivers. I must have driven past countless bridges with non-vertical walls or buttresses. But then I’m in Europe. Do USians get freaked out by anything that isn’t perpendicularly upstanding?
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We have plenty of things that lean, but they look like they are supposed to be leaning. That looks like something is wrong with it, especially with the divided attention of someone driving and seeing that out of the corner of their eye.
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Well, I guess you have to be there.
In the video it just looks a bit lean-y, and not unnaturally and not “leaning dangerously”. 
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Maybe shoot this with a lens that better approximates how the human eye sees things if you are trying to prove a point?
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It’s an odd thing to have to explain over Zoom before that third cup of coffee, but the NCDOT engineer’s explanation is not a model of clarity.
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It’s telling how the resident engineer (RE) implies that because the contractor built the wall straighter, the visual effect is that the wall appears to be leaning–not that the RE would have anything to do with the aesthetics of the bridge. He was just there to make sure the bridge was built as designed. But of course, if the contractor had built it as designed, which was less straight, naturally, there likely would be no leaning effect and quite a bit less nausea. So there you have it, it was the RE’s fault after all. 
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Based on the video it looks like there’s a bit of a bank on the corner as it passes under the bridge, which could lead a driver to believe the wall is at an angle, which it is, relative to the surface they’re driving on.
Is “flyover bridge” a common term? I have only heard them called overpasses or on/off ramps.
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Yep. This is the shot that makes the point. The wall is madly foreshortened in this view, and it does look crooked and buckling. But it isn’t. Get over it. Yes, in an ideal world we would rebuild everything until it looks right, but there are better ways of spending money just now.
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It is designed that way. I think the drivers are imagining it’s a simple retaining wall, not a “structure”. Most people’s experience with home-built retaining walls is that they’re stacked block affairs that are notorious for buckling outward in the rain (especially bad if they’re poorly drained.) Abutment walls like these are critical to maintaining the integrity of the ground around the bridge abutments, and are engineered to contain the soil. This is especially important for when the soil becomes wet and heavy.
Here’s a particularly crappy stacked block retaining wall built around the raised parking lot of a Home Depot. This is why you should panic if you see a wall bulging outward:
This wall was incredibly poorly designed. It catches all the run-off drainwater from the paved parking lot above, and when they first built it it didn’t take but a few years for the thoroughly soaked soil to bulge it outwards. The parking lot above started sinking into the hole! I assume the contractor who built it was eventually held responsible, but really everyone who signed off on this should have shared in the blame. From the store’s architects to the city engineers, everyone should have red flagged this long before it left the blueprints.
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Wow, those blocks are for residential landscaping. To build what appears to be a 10’ vertical seems a bit unwise.
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It ranges from 10’ to over 20’ at the tall end. It’s way, way too tall for that kind of construction.
And on a commercial property, no less!
EDIT: I forgot to point out the trees now growing along the edge. Trees with roots. Long, long, pushy roots. It’s like they can’t help themselves from making poor decisions.
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They probably put those there to hold it in place. 
Edited for typo.
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It is standard usage in the UK
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As if drivers in those parts didn’t already have enough to worry about with the can-opener bridge: http://11foot8.com/
