When I walk, I see a LOT of nails embedded in the sidewalk. In asphalt AND in concrete. They look like 8d nails or thereabouts–not roofing nails. And they’re often in the middle of the sidewalk (not precisely, but not near the edges).
Any ideas why these are so common?
Survey markers.
Thanks. I had sort of wondered about something along those lines but had no real knowledge thereof.
Are these meant to persist, or is it just that it’s easier (and perhaps better) to drive the nail in than to remove it and leave a hole?
They’re meant to persist. At first they will having marking ribbon or paint. The really important locations will have driven rebar with an aluminum cap with the surveyors info. That doesn’t work in pavement (although you will see drilled/adhered markers sometimes).
It varies, obviously. There are a bunch around our local university. There are a few near some local landmarks. Lots near the local dept of cartography.
There are absolutely none down on the highway interchange where I walk my dogs.
I think the simple “nail in the tar” is a student thing. A much more hardy bolt sunk into the tar, and painted yellow, is a sign of a more professional survey.
But I am not a a surveyor.
There are benchmarks around but they don’t look much like nail heads.
Yeah, I don’t know that they are “driven” there as much as put there when the cement is fresh or the asphalt is new and more pliable. At any rate, I was thinking they were used as temporary markers during construction and then just left there because it is not worth the time/cost to remove them.
On my street, and others I have seen, there are what looks like a small pipe-top visible, but not protruding, in the street. I don’t know what it was for, but assumed it was used for something during construction of the neighborhood, and just left there.
Just a linguistic comment. Using pavement to mean sidewalk is a characteristic of the Philadelphia. I had to leave to discover that to most people, the pavement is the street.
Anyway, I have never seen nails in the sidewalk. Look for a man with a hammer.
Sometimes we use nails to designate where finished grade is, i.e., pour concrete to the top of the nail.
Well, this got more interesting than I’d thought!
Re Philadelphia: I was born north of NYC, grew up in Ontario, moved to Virginia 35 years ago. So on average, I guess that puts me in Philly 
but I’ve used “pavement” to mean “the hard stuff, wherever it is” and never had any confusion, so I don’t know what to tell ya.
These are JUST nails, heads smaller than a roofing nail. So maybe not surveying marks–when I saw that, I was thinking more like temporary marks.
Mystery…perhaps continues? I don’t think it’s kids, as there are too many spread over too wide an area (we have many miles of paved trails in our subdivision and I’ve seen these miles apart, as well as on concrete, where I doubt kids would be able to embed one).
Try to see if there is any logic to the location of the nails.
If they form a straight line at regular intervals , they may be survey markers for construction/
If they are halfway between two buildings, they may be property-line markers.
Also, are they at the (“imaginary”) intersection between two fence lines? Or at a point where the fence line would extend towards the street? ,Ttat’s another sign of property-line markers.
I worked as a surveyor for a year or so, and we would use nails pounded in to concrete or asphalt as temporary benchmarks when conducting surveys for property lines and during construction. We would abandon them in place when we were done. Occasionally we would need to go back to a location, and we would reuse these temporary benchmarks if they were still there. Of course we would re-locate them as part of the process to make sure nothing had changed.
rebar, pipe driven into the ground, concrete or even small marble monuments are often installed as permanent property boundary markers. Just depends when and where.
Nothing to do with surveying but I was watching The Tall T directed by Budd Boetticher. In the commentary he said, for a scene where Randolph Scott is walking in a slot canyon uphill toward the camera, that he and Charles Lawton, Jr., the cinematographer were scouting locations near Lone Pine. When he found a good spot and told Lawton it was perfect, Lawton started looking around, then kicked at the dirt a bit to unearth an eyebolt driven into the rock.
“Me and John Sturges were here ten years ago for The Walking Hills.”
Regular property boundary markers are boring.
We had a job one time to survey an old ski resort property that straddled the NY/VT border. Part of our summer was spent cutting lines of sight to locate the State boundary markers, in the middle of some dense forested hills and mountainsides, so we could establish the rest of the property bounds.
A lot of the legal descriptions I deal with use these markers: “From a spike marking the northwest corner of Section12, Township 24, Range 43, proceed 244 feet South…”
I’ve looked, don’t see anything obvious. But they’ve been there 30+ years, so who knows!
