Overhead Sign Gantrys -- The Good, The Bad, And The Ugly

[J N Winkler]

Is there a reason why they choose a Dutch name? "vierendeel" means something like a "four-part" or something.

Vierendeel trusses owe their name to Arthur Vierendeel (1852-1940), a Belgian structural engineer born in Leuven (Flemish-speaking Belgium).  English Wikipedia's article on trusses has a section explaining the distinguishing features of Vierendeel trusses.

http://en.wikipedia.org/wiki/Truss

[myosh_tino]

I'm actually rather surprised nobody has posted any pictures of sign gantries that look similar to what Nevada uses.  I thought these were more common.

These type of sign bridges are the most common in California with the "Box Beam" being the next most common.  Like Nevada, all signs on a particular sign bridge are the same height but all signs are flush to the bottom of the sign bridge.

US 101 at CA-85


I-680 at CA-84


I-680 at I-780


Oh, and we do tubular in California too...

[roadfro]

These type of sign bridges are the most common in California with the "Box Beam" being the next most common.

Yeah, in my travels through California, I've seen this style (which Wikipedia identifies as a "Pratt Truss") more frequently than anything else CalTrans uses.  I would imagine box beams or enclosed trusses use a similar design, just covered up by panels.

To me, a lot of these other designs--especially where part of the sign hangs below the truss/pole--seem as if the signs would be harder to secure and would be more vulnerable to getting hit by an oversize vehicle.  (I'm sure the latter isn't really a problem, but it just seems that way.)  They also seem to need ridiculously long lighting supports as well, which add to that perception.

[NJRoadfan]

Best Endangered or "Antique" Gantries:  Those Art Decos still on the Jersey Turnpike.

NJDOT during their extensive reconstruction of the NJ-139 viaducts actually put up a new replica of this style gantry. You can see it in the background of this picture.



The only signs in that area with that style were strictly NJTP directing traffic to the Newark Bay Extension. While someone was trying to be period correct (note the street lights), the old gantry there was simply something resembling an I-beam. That part of the viaduct predates the NJTP by about 20 years and would never have had that style originally.

[agentsteel53]

wait, are you saying that the gantry in the second photo is *not* the old one in the first photo?  They made a new one just like it?  Excellent!

(Or, if they kept the old one and moved it ... also excellent!)

[mightyace]

I drove from Spring Hill to Nashville to Clarksville and back Monday and saw at least four different styles of overhead gantries and three different cantilevered designs.  The most popular design has a triangular shape for the horizontal bar.  (Two in the front, of course, and one in the back.

Franklin, TN introduced some tubular gantries at the new McEwen Drive exit (#67) off of I-65.

Tennessee seems to love extreme cantilevered signs.  As many of you know, this bit them in the hindquarters last year when one of them fell down on I-65 south near exit 68!

As I get pictures, I'll post them.

[Marc]

Tennessee seems to love extreme cantilevered signs.  As many of you know, this bit them in the hindquarters last year when one of them fell down on I-65 south near exit 68!

I remember, probably close to 10 years ago now, when a cantilevered sign fell on I-240 in Memphis. I believe it was the 1/2 mile guide sign for Perkins Road.

Here's a perfect example (this design is also one of my favorites BTW):

[mightyace]

^^ Thanks, Marc.

There one on I-65 north with approach signs for exit 74 that has TWO BGSs of that size on a cantilever like that!

The one that fell near exit 68 was also of that type, it has since been replaced with a full sign bridge.

[Alex]

The oldest freeway era sign bridges used in Delaware resemble this assembly:



Then there were a handful of this style sign bridge used:



From that 1st style pictured, Delaware moved on to this style, mainly used in the 1980s:



The newest standard style, found on the widened Interstate 95 and elsewhere, is this:



A customized sign bridge is used in places too, such as this one on U.S. 202:



And lastly, a sign bridge style from eons ago, this assembly near the Cape May Lewes Ferry:



It should be noted that a similar sign bridge was posted on U.S. 13 south/40 west near their split at State Road until around 1990.

[timhomer2009]

The ones in Texas are quite drab.  I think they're changing them a lot because of the switch to Clearview.

They just replaced one in San Marcos (where I live) on I-35, and it held up traffic several miles.

[agentsteel53]

They come in a variety of colors including tan (Interstate 280 north of Cupertino - example), mint green (Interstate 280 thru downtown San Jose - example), red (CA-85 between Almaden Expwy and I-280) and forest green (CA-85, Exit 1B/Bernal Road).

there is also an orange-tan color on CA-24 approaching the Caldecott Tunnel.

[Michael]

Tennessee seems to love extreme cantilevered signs.  As many of you know, this bit them in the hindquarters last year when one of them fell down on I-65 south near exit 68!

I remember, probably close to 10 years ago now, when a cantilevered sign fell on I-240 in Memphis. I believe it was the 1/2 mile guide sign for Perkins Road.

Here's a perfect example (this design is also one of my favorites BTW):

There's one I'm aware of in Central New York that's that long, but it just has an exit gore sign on it.  Here's the Google Street View of it.

EDIT: Street view is fixed!

[Marc]

The ones in Texas are quite drab.  I think they're changing them a lot because of the switch to Clearview.

They just replaced one in San Marcos (where I live) on I-35, and it held up traffic several miles.

Agreed. Here are examples of Texas gantries.

Bridge:


Bridge (spanning all mainlanes):


Cantilever (BTW, I detest Houston's excessive use of mast lighting):


Concrete Sign Bridge (taken from the new Katy Freeway):


EDIT: The TxDOT Houston Division has recently removed all the undercarriages and lighting from all overhead gantries. The signs have not been replaced, rather, the undercarriages have just been sawed off. They left evidence of I-beam "nubs" under many signs.

EDIT 2: I have noticed that Texas is starting to make more use of the Tubular Arch. Marsha Sharp Freeway in Lubbock is being constructed with the Tubular Arch and there are also some along I-10 in El Paso. There is also one that went up here in Houston on Post Oak Blvd at the overpass of the new Katy Freeway.

[burgess87]

EDIT: The TxDOT Houston Division has recently removed all the undercarriages and lighting from all overhead gantries. The signs have not been replaced, rather, the undercarriages have just been sawed off. They left evidence of I-beam "nubs" under many signs.

How are they lighting the signs, then - with the high mast towers?  I haven't been to Houston in some time, but I would think at least some sign-mounted lighting would be warranted.

Unless they want to start backlighting those signs . . .

[J N Winkler]

How are they lighting the signs, then - with the high mast towers?  I haven't been to Houston in some time, but I would think at least some sign-mounted lighting would be warranted.

They aren't lighting these signs at all.  These lighting installations were removed as part of several large guide sign replacement contracts done in the early 2000's which changed out button copy in favor of retroreflective sheeting.  If memory serves, the largest of these contracts (let in early 2003) had something like 250 sign design sheets, with four to six sign designs per sheet.

TxDOT carried out a major guide sign replacement initiative all over Texas, not just in the Houston District, to replace existing button copy with retroreflective sheeting.  I am not sure exactly when this program started, but I think it was underway by 2000 and it ran at a rate of about one guide sign replacement contract per month letting until 2005.  Most of these contracts had CCSJs of the form 09AA-XX-YYY where "AA" is the TxDOT district number (this coding implies "districtwide" rather than confined to a single route, in which case the contract goes out with a CCSJ derived from the CS of the route under consideration).

I have a collection of TxDOT signing contracts which includes most if not all of the major guide sign replacements done during this period.  I have broken out all the pattern-accurate sign design sheets and moved them to a separate folder.  At the moment the total sheet count in this folder (which includes sign design sheets from turnkey construction contracts as well) is 8620, of which 2724 sheets come from 09AA contracts.  Signing in Texas is a massive business.

[Ian]

Tennessee seems to love extreme cantilevered signs.  As many of you know, this bit them in the hindquarters last year when one of them fell down on I-65 south near exit 68!

I remember, probably close to 10 years ago now, when a cantilevered sign fell on I-240 in Memphis. I believe it was the 1/2 mile guide sign for Perkins Road.

Here's a perfect example (this design is also one of my favorites BTW):

There's one I'm aware of in Central New York that's that long, but it just has an exit gore sign on it.  Here's the Google Street View of it.  For some reason, Street View keeps facing the wrong way, so you have to rotate the image to the right to see it.

NH, RI, and MA use those aswell.

NH: http://picasaweb.google.com/Iansignal/NewHampshireTrafficSignalsAndRoadSigns#5350720044231910450
RI: http://picasaweb.google.com/Iansignal/RhodeIslandTrafficSignalsAndRoadSigns#5324327431283977026
MA: http://picasaweb.google.com/Iansignal/MassachusettsTrafficSignalsAndRoadSigns#5322875952171548994

Oh, and so does Delaware:
http://picasaweb.google.com/Iansignal/Clearview#5292759604241855330

[Michael]

^^^ On the other extreme, here's one that could be cantilevered, but isn't.

[burgess87]

How are they lighting the signs, then - with the high mast towers?  I haven't been to Houston in some time, but I would think at least some sign-mounted lighting would be warranted.

They aren't lighting these signs at all.  These lighting installations were removed as part of several large guide sign replacement contracts done in the early 2000's which changed out button copy in favor of retroreflective sheeting.  If memory serves, the largest of these contracts (let in early 2003) had something like 250 sign design sheets, with four to six sign designs per sheet.

TxDOT carried out a major guide sign replacement initiative all over Texas, not just in the Houston District, to replace existing button copy with retroreflective sheeting.  I am not sure exactly when this program started, but I think it was underway by 2000 and it ran at a rate of about one guide sign replacement contract per month letting until 2005.  Most of these contracts had CCSJs of the form 09AA-XX-YYY where "AA" is the TxDOT district number (this coding implies "districtwide" rather than confined to a single route, in which case the contract goes out with a CCSJ derived from the CS of the route under consideration).

I have a collection of TxDOT signing contracts which includes most if not all of the major guide sign replacements done during this period.  I have broken out all the pattern-accurate sign design sheets and moved them to a separate folder.  At the moment the total sheet count in this folder (which includes sign design sheets from turnkey construction contracts as well) is 8620, of which 2724 sheets come from 09AA contracts.  Signing in Texas is a massive business.

Ah, I see.  It's been six years since I've been back to Texas (when I was there last, Clearview was just a dream), so the only evidence I've had of change is pictures.  Thanks for the explanation!

[OT]  I'd like to see a "How It's Made" segment on road signs.  That'd be sweet.  I've never seen a sign fabrication shop.  [/OT]

[Michael]

[OT]  I'd like to see a "How It's Made" segment on road signs.  That'd be sweet.  I've never seen a sign fabrication shop.  [/OT]

I LOVE that show!  And yes, a sign shop would be an awesome segment, especially the BGSes and sign bridges.

[wisp2007]

These hideous things from Seattle, WA date back to the 50s. 



- - - -

These are square arches, as opposed to tubular ones.

[hbelkins]

[OT]  I'd like to see a "How It's Made" segment on road signs.  That'd be sweet.  I've never seen a sign fabrication shop.  [/OT]

I LOVE that show!  And yes, a sign shop would be an awesome segment, especially the BGSes and sign bridges.

They've actually done a segment on road signs, but they were surface signs instead of guide or panel signs. My wife was watching one night and woke me up to see it.

[Chris]

I've been in a sign manufacturing plant. Those overhead signs are actually a lot bigger than they look from a car if you stand next to them.

[Scott5114]

I've been in a sign manufacturing plant. Those overhead signs are actually a lot bigger than they look from a car if you stand next to them.

I'll say!

[Duke87]

Now this is rather goofy:


Because, you know, it's better to reeeaaach all the way over from the left rather than just putting the support to the right.

[kurumi]

What bugs me about California gantries:
- all signs forced to same height, regardless of content
- exit "tabs" jammed into sign panel

This sign, on CA 237 EB at I-880, is all kinds of wrong: http://www.westcoastroads.com/california/images201/ca-237_eb_exit_009a_03.jpg (page: http://www.westcoastroads.com/california/ca-237.html)

It doesn't help that the 3rd lane from the left could be used for CA 237 EB (one optional and one exit-only lane); I-880 south (one optional exit lane); or I-880 north (keeping left) without changing lanes. How do you express that on one sign gantry?