reflective sheeting over the years

[agentsteel53]

as most of them are rather ugly, lacking any distinctive character except being outdated, i.e. using button copy

there is nothing wrong with button copy - but Conn sure makes things difficult by putting a retroreflective background on it, making the buttons dang near illegible.  Dunno which genius came up with that idea, but I've seen the combination in Arizona, Ohio, Oklahoma, West Virginia, and several other places I can't think of offhand. 



in no place does it actually work well.  explain to me again why the backgrounds of signs have to glow at night, destroying the contrast and the legibility?

[wytout]

I have no idea.  I would think that if the background was NOT retroreflective and the legend WAS retroflective on any kind of BGS, it would provide optimum readability.

[J N Winkler]

Reasons for retroreflective sign backgrounds:

*  The MUTCD requires that signs must be illuminated or retroreflectorized to appear the same by night as they do by day.  Retroreflective sheeting is cheaper than sign lighting.

*  Retroreflective backgrounds enhance target value, thus allowing signs to be seen earlier.  For similar reasons, fluorescent yellow sheeting (rather than ordinary yellow sheeting) is used for "EXIT ONLY" bottom panels in many states.

It is true that having retroreflective legend on a nonreflective background enhances contrast, but this is not necessarily a good thing.  It is a benefit to motorists to be able quickly to distinguish signs having "action" messages (e.g. green-background advance guide signing) from signs which can safely be ignored (e.g., any sign with a blue background when the motorist does not need motorist services).  Moreover, whole-letter retroreflectorization against a dark background can lead to a halation problem, which is more severe for Series E Modified than it is for Clearview.

Some states, like Arizona, now use microprismatic sheeting (which is brighter and more expensive) for foreground legend and either super engineer-grade or high-intensity sheeting (both of which are dirt cheap) for sign backgrounds.  This makes signs much cheaper while maintaining target value and good reading contrast.  With Clearview 5-W now the standard for freeway guide signing in Arizona, the problem of button copy looking like "speckled dark" against super engineer-grade backgrounds essentially no longer exists for new signs in Arizona.

[agentsteel53]

what's the difference between super engineer-grade and the regular stuff? 

I just have the general idea that high intensity is 3x as bright as engineer grade, and microprismatic (diamond grade) is 10x as bright.

[J N Winkler]

Not sure--AIUI, they both use the same enclosed-lens technology, but super engineer-grade is supposed to be slightly brighter and last a little longer.  Richard Moeur (who has managed several Arizona DOT guide sign replacement contracts and used to be a MTR regular, though he hasn't posted regularly for a number of years now) used to make a big point of the fact that ADOT never used a sheeting material inferior to super engineer-grade.  Last I heard (a number of years ago), ADOT was thinking about standardizing on high-intensity sheeting for sign backgrounds, since it had dropped considerably in cost soon after microprismatic sheeting became widespread.

[agentsteel53]

ADOT never used a sheeting material inferior to super engineer-grade

I've seen plenty of Silver Scotchlite Arizona shields ...



did he refer just to guide signs?  those were non-reflective with Stimsonite until quite recently.

[J N Winkler]

He was referring to current practice at the time he was posting (roughly 1998 to 2004).  I think, but can't be 100% sure without digging into my pile of Arizona DOT sign design sheets, that ADOT used Scotchlite (essentially, ordinary engineer-grade sheeting) for ground-mounted freeway guide signs from a relatively early time--perhaps mid-1960's--while overhead guide signs had illumination but no background retroreflectorization.

Edit:  Now checked.  An assortment of sign design sheets from various lengths of I-10 west of Phoenix (earliest December 1970, latest mid-1974) specifies either "Reflectorized Green" or "Reflectorized Interstate Green" for what are manifestly ground-mounted guide signs on the Interstate mainline, and "Opaque Green" for the crossroads signs.  Opaque green on the overhead guide signs will be a little harder to check though (where were there overhead guide signs in Arizona in the early 1970's?).

Edit II:  Came across some Pinal County I-10 sheets.  It was much less hard to check re. overhead signs than I expected.  Yes, they were opaque green (from 1969 at least), though yellow bottom "EXIT ONLY" panels were retroreflectorized.

[agentsteel53]

Scotchlite (essentially, ordinary engineer-grade sheeting)

is there a subtle difference between the two?  I've always thought the two to be synonymous.

silver scotchlite - the first sheeting, invented 1938, fades to brown or green depending on variant.  Heat transfer application.
engineer grade scotchlite - 1950, pressure-sensitive application, and fades to slightly dull color and loses reflective qualities, but doesn't discolor noticeably.

original high-intensity - 1971, has honeycomb network, flakes off very easily, also fades to dull rather quickly

then there is the new prismatic high intensity, which apparently is the same reflectivity as the original, but is much more durable. 

diamond grade - microprismatic sheeting?  dunno what year offhand (late 80s?), extra crazy bright.  I'd thought they'd use this only for stop signs, but apparently AZ is using them for shields?

I've seen several uses of "mixed reflectivity", for example on interstate shields with the number being hexagon high intensity, and the background and the word "INTERSTATE" only engineer grade. 

[agentsteel53]

where were there overhead guide signs in Arizona in the early 1970's?).

here are some horrible photos of some guide signs that were in place in 1971. 





I am guessing the first one is an older style - black with nothing reflective - while the interstate shields appear to be button-copy, and I cannot tell if it is a green or black background.  In any case, look at that, an I-410 shield!

(BTW, giving passing mention to the original topic: these are great examples of how NOT to take photos of BGSes, BBSes, etc.)

[J N Winkler]

I can't speak to variations in Scotchlite--it is actually new information to me that it was invented as long ago as 1938 and that there were multiple generations of it with different fading behavior.  The sources I have (mainly old plan sheets) don't specify sheeting type or brand (bad form to specify a proprietary product in Federal-aid construction . . .), so it is not necessarily true that it was Scotchlite (rather than a different sheeting brand) which was used for the retroreflective green backgrounds.  I am, actually, also assuming that the retroreflective sheeting used for freeway guide sign backgrounds in Arizona in the early 1970's would have been enclosed-lens.  I don't have the sign schedule sheets within easy reach, so in principle they could have used encapsulated-lens sheeting, but it would be illogical and weird to use such an expensive material on ground-mounted signs and leave the overhead signs opaque.  In the absence of a sheeting type specification, a contractor bidding on the basis of high-intensity sheeting would also have been uncompetitive on price.

As to shields--yes, I've seen microprismatic sheeting used on shields in Arizona, though there are still plenty of super engineer-grade shields around.  I photographed specimens of both when I was in southern Arizona last January.  My personal impression is that prismatic high intensity appeals to state DOTs like MoDOT which want the clear colors associated with microprismatic sheeting but are too cheap to shell out for the real thing.  (It has always been my impression that encapsulated-lens sheeting has a grayish-silver cast even when fresh.)

[J N Winkler]

The first of the pictures you posted doesn't look anything like the sign designs in my Arizona DOT pile (the earliest of which, I think, dates from 1965).  I also can't tell whether opaque green or black background is in use, but incline to suspect the latter.

Two possibilities come to mind:

*  These were temporary signs, placed in anticipation of a future permanent signing contract.  I have never seen an Arizona DOT construction contract which calls for placement of temporary signing, and permanent signing was done in separate contracts until about the early 1980's.  This would tend to imply the signs were fabricated in the departmental sign shop and placed by department forces.

*  These signs were placed by the local agency (City of Phoenix?), either as part of contract work or through direct labor.

In general, the use of temporary signing during the peak period of first Interstate construction is not something I have found to be widely discussed, or even understood very well, within the road enthusiast community--Randy Hersh is the only expert on the subject I personally know of.

[agentsteel53]

what is the difference between enclosed- and encapsulated-lens sheeting?

the predecessor to scotchlite was glass beads applied directly to a substrate - either by covering the wet white paint with it, or mixing it into a clearcoat and applying it on top of dry white paint.  This technique was used as early as the late 1920s, as a competing idea to glass cateye reflectors.  Same optical principle, just a different scale.  Here is an example of a Kentucky shield with glass bead paint:



this is what happens when the retro-reflective action kicks in.



as you can see, they applied the retroreflective layer *on top of* both the black and the white paint.  Not too smart!  Later variants would roll opaque black over the legend as the *last* step.

As for scotchlite, yes it is always slightly gray.  I have a roll of it that I acquired in 2006, brand new, and it is indeed gray.

In the very beginning, the 3M product was called Scotchbrite, and they renamed it I think in 1950 when they came out with the new variant.  They continued to make the Silver Scotchlite (aka Scotchbrite) until the 70s, as it was cheaper, though more difficult to apply at its destination due to the heat-transfer requirement.  It was this heat-activated glue that turned all sorts of weird colors due to UV exposure.  It did, however, form itself nicely to embossed designs, which engineer grade does not - the heat made it sufficiently flexible.  This way, older signs could be re-surfaced and brought up to spec.  North Dakota did this quite a lot, starting in the late 30s.  Here is a 1920s shield that has been resurfaced.  

(Nowadays, the Scotchbrite brand name refers to a scouring pad!)



if you look closely at the O in North, you can see the original white paint where the sheeting has fallen off.

I have a photo somewhere of a roll of Scotchbrite labeled "1941"; will have to dig it up.  

Scotchbrite had its competitors - I remember seeing an ad for a product called Reflectolite from 1947 that appeared to be a similar sheeting product.  No idea about its reflective characteristics, or its fading.  Gotta dig up that photo, too.

The most interesting Scotchlite variant of the 1950s was "black scotchlite", which was exactly that.  Black sheeting, that glowed under direct light, thereby causing a color inversion.  Here is an example.  This is not a good photo at all, but the "53" is in black scotchlite, while the rest is non-reflective, including the background paint that is of very low quality!



one final example of various Scotchlite performance issues:



note the Vermont US 2.  The town of Waterbury needed a "2" shield so they dug one out of the backroom, peeled off everything except the number "2", and stuck it up there.  This resulted in two different "ages" of Scotchlite - the layer that had been exposed for 50+ years has lost nearly all of its reflectivity, while the just-peeled-off "new" Scotchlite still works fine.  So, counterintuitively, this is what the shield looks like at night.



Not so good!  The state route 100 is showing similar results, as the original white background has lost all of its reflective character, and only places where the number is peeling off are in any way reflective.

As for the NO PARKING sign, that is red scotchlite on a non-reflective background.  In that case, the red has faded (as red tends to do), but the retroreflective elements still work.  This appears to be Engineer Grade, not Silver Scotchlite.  

[agentsteel53]

The first of the pictures you posted doesn't look anything like the sign designs in my Arizona DOT pile (the earliest of which, I think, dates from 1965).  I also can't tell whether opaque green or black background is in use, but incline to suspect the latter.

could the 60/70/89/93 and 69 signs date back to even older than 1965?  Maybe late 50s?  Black signs with outline shields tend to be a late 50s specification. 

[hbelkins]

as most of them are rather ugly, lacking any distinctive character except being outdated, i.e. using button copy

there is nothing wrong with button copy - but Conn sure makes things difficult by putting a retroreflective background on it, making the buttons dang near illegible.  Dunno which genius came up with that idea, but I've seen the combination in Arizona, Ohio, Oklahoma, West Virginia, and several other places I can't think of offhand. 



in no place does it actually work well.  explain to me again why the backgrounds of signs have to glow at night, destroying the contrast and the legibility?

When was this photo taken? The button copy is gone from along I-68. Only button copy I've seen on the green guide signs in either direction is the supplemental "Kingwood" signs at the WV 26 exit.

[J N Winkler]

could the 60/70/89/93 and 69 signs date back to even older than 1965?  Maybe late 50s?  Black signs with outline shields tend to be a late 50s specification. 

IIRC, outline shields were dumped in 1962, while black background lingered as an option for non-Interstates until 1971.  So, yes, I'd say it is likely these signs predate 1962 at least.  Arizona SR 69 is, of course, now I-17, but if it had not yet been decided that I-17 would follow SR 69, it would have been reasonable for these signs to have black background.

I am actually not sure whether Arizona DOT (or its predecessor agencies) signed any freeways pre-1971 which were not Interstates--I am off to the Azhighwaydata.com site to check.

Re. enclosed-lens and encapsulated-lens sheeting:  these are generic names for types of retroreflective sheeting based on how the reflective material is combined with the pigmented film.  These terms tend to be encountered most often in patent descriptions and technical reports.  Enclosed-lens sheeting corresponds to engineer grade and super engineer grade, while encapsulated-lens sheeting corresponds to high-intensity.

Nowadays sheetings are classified (and, I would expect, specified for construction) according to performance type rather than construction.  In recent issues of sheeting standards like ASTM D4956, the performance classifications outnumber the different forms of sheeting construction.  This allows more granularity in specifying sheeting type by application--for instance, some types of microprismatic sheeting are better suited for use as roadside reflectors while others are suitable for large guide signs, and this is reflected through the use of different type classifications per ASTM D4956.

It is my understanding that WSDOT used something similar to the "black Scotchlite" concept to sign night speed limits on the same sign blanks as daytime speed limits.  The overall sign background was not retroreflectorized, while the legend "NIGHT" and the night speed limit value were both reflectorized.  The black text (for the daytime speed limit) was overlaid in such a way that "NIGHT" and the night speed limit "glowed" in the dark while everything else on the sign was obscured.

[agentsteel53]

IIRC, outline shields were dumped in 1962,

the federal standard for "no outline shields" was in the 1961 MUTCD.  CA started to obey in 1961, but dragged their heels since they had so many green signs with outline shields up.  Finally they went and changed the surface-level shields to green, too, bringing the green signs back into spec.  Surface level shields have a 3-5 year lifespan, while the overheads were designed for 30 (and indeed most of them look great after 40-50!)

while black background lingered as an option for non-Interstates until 1971.

this was a federal standard?  My 1958 AASHO interstate manual specifies green, but of course address interstates only.  I know CA switched in 1958, and a lot of states simply did not have freeways until the interstate system.  Conn used blue on their turnpike, and I think NY did on their thruway too... when did those states switch? 

I am actually not sure whether Arizona DOT (or its predecessor agencies) signed any freeways pre-1971 which were not Interstates--I am off to the Azhighwaydata.com site to check.

was there a US-60 freeway section then in Phoenix? 

Re. enclosed-lens and encapsulated-lens sheeting:  these are generic names for types of retroreflective sheeting based on how the reflective material is combined with the pigmented film.  These terms tend to be encountered most often in patent descriptions and technical reports.  Enclosed-lens sheeting corresponds to engineer grade and super engineer grade, while encapsulated-lens sheeting corresponds to high-intensity.

gotcha.  Somewhere there is an excellent photo of EG scotchlite, and it basically looks like glass-bead paint, except on a much more microscopic level.

It is my understanding that WSDOT used something similar to the "black Scotchlite" concept to sign night speed limits on the same sign blanks as daytime speed limits.  The overall sign background was not retroreflectorized, while the legend "NIGHT" and the night speed limit value were both reflectorized.  The black text (for the daytime speed limit) was overlaid in such a way that "NIGHT" and the night speed limit "glowed" in the dark while everything else on the sign was obscured.

Florida did something like this as well.  This was on a white-background sign, so it was plain old scotchlite vs non-reflective that showed the difference at night, while in the day it was black vs. white.  I know Steve Alpert's site has an example of such a thing, but I cannot find it offhand.

[J N Winkler]

Yup.  For a while California intended to comply with the "no outline shields" requirement by putting the state route shields in white on freeway guide signs, but that did not last long.  I have guide sign drawings with white-background shields but I am not aware that any were actually installed in the field.  And yes, California unilaterally adopted green background for all guide signing in 1958, and it was far from the only state to do so--plenty of others were using green (including retroreflective green) for guide sign backgrounds on non-Interstates in the early 1960's, if a Scotchlite advertisement in a contemporary issue of Traffic Engineering (as the ITE Journal used to be called) can be believed.  The option to use black background for guide signs was in the 1961 MUTCD (first of the modern series of MUTCD editions prepared under federal supervision, in this case the Bureau of Public Roads) but had been withdrawn by the time the 1971 MUTCD (compiled by FHWA) appeared.

I am not sure how old the Superstition Freeway in Phoenix is, though the US 60 and "Former Arizona state routes" articles in Wikipedia suggest it was, or at least parts of it were, in existence by 1970.  Originally it was SR 360--the US 60 designation was applied later, around 1992.  The Azhighwaydata.com site has no listing for SR 360, so I assume records pertaining to it were transferred over to US 60.  There are just a few very old signing and marking jobs which look more like intersection work on the surface-street parts of US 60.

General search page:

http://www.azhighwaydata.com/engineeringrecs/search.asp

Statewide US 60 results (will take a while to load--884 records):

http://www.azhighwaydata.com/engineeringrecs/search.asp?Road=%20%20U%20060&BKMP=&EKMP=&Show=False&Tracs=&Fed=

Edit:  H. Gene Hawkins says that the option to use black background on conventional-road guide signs was not dumped until 1978, although the 1971 MUTCD established green as the standard for freeway guide signs:

http://tcd.tamu.edu/documents/MUTCDhistory3.pdf

[agentsteel53]

I have guide sign drawings with white-background shields but I am not aware that any were actually installed in the field. 

There are.  Here is a 118 from 1962 on a pole-mounted sign with internal reflectors:



here is an 89 on an overhead with no reflectors:



note the white 99 shield, which also is a post-1961 style.  The white shields are very rare to find for decommissioned routes.

And yes, California unilaterally adopted green background for all guide signing in 1958

with implementation following in due course.  I have seen a black guide sign with a '61 stamp.  In fact, I believe I made an error when I said 1958, because the earliest green sign I have seen is 1959, and for 1959 I have seen quite a few black signs. 

There may be '58s though as trial runs - CA has a way of experimenting for a few years before adopting a standard.  For example, the formal switch from porcelain surface-level green signs (like the 118) to metal-plate signs with individual button copy letters is mid-1963, but there is a single example I know of with a '60 stamp that must've been a trial run. 

(In fact, a 134 sign that is metal-plate has a white shield - the sign went missing as late as 2008, and had a '63 stamp.  I need to upload a photo to the shield gallery!)

that said, the outline shields did not vanish instantly.  I have seen metal-plate signs with outline shields - some I-5 green signs from 1963 in the Grapevine show evidence of US-99 outline shields scraped off. 



and, every once in a while, someone completely looks up the wrong standard - here is a late 1990s vintage sign with an outline shield!



that is a hideous picture.  The sign has button copy on a non-reflective green background.  And here is a city-of-Atascadero install from the early 2000s.



and, just for fun, here's a photo of a '60 - the last "classic" outline US shield left in CA! 



there is a 107 state shield left as well, and possibly this 118 is still around.  Note the "extra angular" spade shape on the pre-1961 shields.

and it was far from the only state to do so--plenty of others were using green (including retroreflective green) for guide sign backgrounds on non-Interstates in the early 1960's, if a Scotchlite advertisement in a contemporary issue of Traffic Engineering (as the ITE Journal used to be called) can be believed. 

can you email me please a scan of that Scotchlite ad?  Washington is one state that used retroreflective green in the early 1960s, on I-5 (US-99), according to a friend of mine who was born in 1945.  He did not remember if there was button copy as well; he just thought the signs hideous compared to the elegant dark green California signs! 

The option to use black background for guide signs was in the 1961 MUTCD (first of the modern series of MUTCD editions prepared under federal supervision, in this case the Bureau of Public Roads) but had been withdrawn by the time the 1971 MUTCD (compiled by FHWA) appeared.

what is meant by "modern"?  I consider the '48 MUTCD to be the first modern one since it specifies flat shields, reflective sheeting, round font, and other trappings of modern highway signage.

Edit:  H. Gene Hawkins says that the option to use black background on conventional-road guide signs was not dumped until 1978, although the 1971 MUTCD established green as the standard for freeway guide signs:

http://tcd.tamu.edu/documents/MUTCDhistory3.pdf

excellent!  '78 is dang late.  Sounds like the '54 MUTCD supplement *recommending* red stop signs, and the '61 mandating them, including the removal of all yellow ones.

[BigMattFromTexas]

I took this picture with flash of my US 277 shield, and you can see the reflection

[agentsteel53]

it looks like a similar thing is happening to that 277 as with the Vermont 100: where black is flaking off, unworn reflective sheeting is poking through. 

does the shield have a stamp or sticker on the back?

[J N Winkler]

And yes, California unilaterally adopted green background for all guide signing in 1958

with implementation following in due course.  I have seen a black guide sign with a '61 stamp.  In fact, I believe I made an error when I said 1958, because the earliest green sign I have seen is 1959, and for 1959 I have seen quite a few black signs.

Are any of these black signs still standing?  They are rarer than hen's teeth. 

and it was far from the only state to do so--plenty of others were using green (including retroreflective green) for guide sign backgrounds on non-Interstates in the early 1960's, if a Scotchlite advertisement in a contemporary issue of Traffic Engineering (as the ITE Journal used to be called) can be believed. 

can you email me please a scan of that Scotchlite ad?  Washington is one state that used retroreflective green in the early 1960s, on I-5 (US-99), according to a friend of mine who was born in 1945.  He did not remember if there was button copy as well; he just thought the signs hideous compared to the elegant dark green California signs! 

Re. the scan, I'd be more than happy to oblige if I actually had one--unfortunately my Traffic Engineering camera extracts end at 1954.  (I do have beaucoup Scotchlite advertisements from this period, though, including one featuring green-background guide signs on the newly opened Turner Turnpike.  There are also numerous advertisements for prefab Stimsonite button copy letters . . .)  In addition to the advertisement showing the states which used green background on guide signs, Scotchlite had a separate full-page ad which played on the fact that Washington State was using retroreflective green background on freeway guide signs.  The specific example sign was taken from the Tri-Cities area (placenames two of the three--"Pasco, Kennewick, Richland"--with a state route shield for, I think, SR 11-G).  As was common in Scotchlite advertising from the 1950's onward, the Scotchlite-covered signs were shown in glorious full color while everything else was in subdued shades of gray.

I have to go to the Wichita State University library in the relatively near future, however, and when I am there, I will try to dig up and photograph a few of these old Scotchlite advertisements.  WSU's run of Traffic Engineering starts in the late 1940's/early 1950's and is relatively complete, at least until the 1970's.

The option to use black background for guide signs was in the 1961 MUTCD (first of the modern series of MUTCD editions prepared under federal supervision, in this case the Bureau of Public Roads) but had been withdrawn by the time the 1971 MUTCD (compiled by FHWA) appeared.

what is meant by "modern"?  I consider the '48 MUTCD to be the first modern one since it specifies flat shields, reflective sheeting, round font, and other trappings of modern highway signage.

"Modern" is lazy usage on my part--I actually mean "after the War Emergency Edition," since I wasn't sure whether that was compiled directly by the federal government, and didn't want to take time out to look it up.  (In actuality, it wasn't.)

Edit:  H. Gene Hawkins says that the option to use black background on conventional-road guide signs was not dumped until 1978, although the 1971 MUTCD established green as the standard for freeway guide signs:

http://tcd.tamu.edu/documents/MUTCDhistory3.pdf

excellent!  '78 is dang late.  Sounds like the '54 MUTCD supplement *recommending* red stop signs, and the '61 mandating them, including the removal of all yellow ones.

Recommendations are often the camel's nose under the tent flap.

I understand (and route56 may still have the pictures posted somewhere) that black-background guide signs persisted on US 71 in Missouri until the mid-1990's.

[agentsteel53]

(A moderator ought to know width=800)

Are any of these black signs still standing?  They are rarer than hen's teeth. 

here is one that appears to be a City of LA job, and may be as recent as the late 1960s.



this one used to be the main sign on the pole ...



then they added the 405 freeway sign, and moved the black sign to the taller single pole.  Why the taller single pole?  that used to hold a 7 shield, as 405 was highway 7 until 1963!  the newer sign is stamped 1972 on the back, the older one has no stamp.



this one, and its pair about 300 feet away in the opposite direction, date back to 1951.  This is an old US-50 alignment.  Porcelain, neon underlighting, no reflectors, everything about this sign is old!  One of the very very first overhead black guide signs put up in CA.

and here are two from the other side of the country.  On an interstate on-ramp, no less!




Steve A. will argue that these are dark dark dark green; they are certainly darker than the dark dark green that the turnpike started using in the early 1960s.



and as a bonus, here is a sign in Pennsylvania that, from what I can tell, is entirely non-reflective.  It's green, but definitely dates to the late 1950s.

Re. the scan, I'd be more than happy to oblige if I actually had one--unfortunately my Traffic Engineering camera extracts end at 1954.  (I do have beaucoup Scotchlite advertisements from this period, though, including one featuring green-background guide signs on the newly opened Turner Turnpike. 

green guide signs in 1954? I'd love to see that!

I understand (and route56 may still have the pictures posted somewhere) that black-background guide signs persisted on US 71 in Missouri until the mid-1990's.

he does, but I cannot for the life of me find them on his page.  I saw them once and promptly forgot their location.  Richie, any help?

[myosh_tino]

Regarding black guide signs in California, there is also one located on I-5 before the CA-14 interchange north of Los Angeles...

[agentsteel53]

Regarding black guide signs in California, there is also one located on I-5 before the CA-14 interchange north of Los Angeles...

there are some on I-40 westbound heading out of Needles as well.  that one is black because it is a truck sign.  The ones in Needles say "TRUCK LANE" or something similar to indicate the presence of a third lane for the climb.

I believe that Truck Route 5/14 sign is from the 1980s.  It is definitely later than 1971, which is when that interchange was rebuilt following an earthquake.

[ctsignguy]

this was a federal standard?  My 1958 AASHO interstate manual specifies green, but of course address interstates only.  I know CA switched in 1958, and a lot of states simply did not have freeways until the interstate system.  Conn used blue on their turnpike, and I think NY did on their thruway too... when did those states switch? 

i cant speak for the other roads, but the Conn Tpke started swapping blue for green in the starting in the late 60s and accelerated the change mid-to-late 70s...you could still find a few of the original signs as late as the early 2000s, but several of them were redone in green then they disappeared....