States "Mimicking" Other States

[J N Winkler]

Correct me if I'm wrong, but MnDOT also uses laminated-panel signs...and they still use separate exit tabs exclusively.

As does PennDOT for the most part.  The examples shown (and there's at least one or two more around Harrisburg) are to me the exceptions rather than the rule.

Yes, PennDOT has historically used proper exit tabs, as did Caltrans for the 1970's exit numbering experiment and the early exit tab retrofits in 2002 in District 2.  I don't know, though, whether PennDOT made exit tabs the same way as Caltrans and MnDOT.  The basic approach (at least for Caltrans) was to build the exit tab as a separate panel and fasten it to the main sign panel by bolting both main panel and tab to two metal ribs behind the sign.  However, I think that instead of this method, PennDOT may at one time have "blocked out" the tab by running the sign panel frame around the tab border instead of fabricating the tab as a separate panel.

My underlying point is that because the design of laminated panel signs is so heavily focused on the panel frame, there is more of an incentive to cut corners by incorporating the exit tab legend into the main sign panel.  The added length of panel frame is negligible, laminated panel signs do not use thick sheet metal so the added cost in panel substrate is also not large, and while the excess sheeting is a significant cost, it is partly offset by there being at most one or two panels (comprising the main sign) instead of two or three, one of the two or three being the tab.

I know of no examples of this kind of corner-cutting with extrusheet or extruded panel signs, where the cost penalties of excess panel height are heavier.

You would not expect to see this kind of corner-cutting with MnDOT, which is and historically has been so conscientious about freeway guide signing that well over 99% of freeway signing plans from 1959 onward have been pattern-accurate, even back in the 1950's and early 1960's when this involved much tedious work with pen sets and dupe film.  PennDOT in the past has not cut corners this way either--before traffic design was devolved to the districts around 1985, there was a traffic design unit in Harrisburg which produced signing plans for the entire state, all in the same style with pattern-accurate and carefully dimensioned sign panel detail sheets.  I think this involved much tedious work with dupe film too (no signs of computerization like route shields with plotter fonts, letters always filled in rather than outlined, letter alignment tables in typescript).  However, these days both Caltrans and PennDOT are socks-down-leg state DOTs where signing is concerned.

P.S.  Downlighting with proper exit tabs is possible--this is how Arizona DOT lights sign panels in Phoenix.

[oscar]

Hawaii DOT apes Caltrans in many ways, including call box signage, and Botts dots lane markings, among other things.  But I think the "teardrop" shape of state route markers was inspired not by California's vaguely-similar miner's spade marker, but rather by the fact (not emphasized in the tourist brochures) that it rains a lot in many parts of Hawaii.

Alaska DOT&PF seems to follow Washington DOT to some extent, including identical tsunami evacuation signage.

[Scott5114]

AK and WA seem to share a higher-than-normal density of Series E signage rather E(M), as far as I can tell.

[PAHighways]

Wasn't this done because of the proximity to the airport, so pilots wouldn't get confused?

Yes, but it has become a moot point now with all of the other light pollution in the approach corridor.

[PAHighways]

However, I think that instead of this method, PennDOT may at one time have "blocked out" the tab by running the sign panel frame around the tab border instead of fabricating the tab as a separate panel.

From the 60s into the 70s, the exit tabs continued the border of the guide sign.  It wasn't until the 80s when the exit tabs and guide signs had separate borders.

[Brandon]

My underlying point is that because the design of laminated panel signs is so heavily focused on the panel frame, there is more of an incentive to cut corners by incorporating the exit tab legend into the main sign panel.  The added length of panel frame is negligible, laminated panel signs do not use thick sheet metal so the added cost in panel substrate is also not large, and while the excess sheeting is a significant cost, it is partly offset by there being at most one or two panels (comprising the main sign) instead of two or three, one of the two or three being the tab.

The solution to this is found in Illinois and Georgia by continuing the exit tab across the width of the sign.  IMHO, IDOT does it best by justifying the text of the tab to the side the exit is on.  Why CalTrans can't do this is beyond me if they're so worried about wind loading.

[J N Winkler]

From the 60s into the 70s, the exit tabs continued the border of the guide sign.  It wasn't until the 80s when the exit tabs and guide signs had separate borders.

What I am talking about is separate from that.  It is my belief that at roughly the same time that border style was in use, PennDOT bent the sign panel frame (which is behind the signface) around the outline of the exit tab, so that the exit tab was an integral part of the main sign panel.

The solution to this is found in Illinois and Georgia by continuing the exit tab across the width of the sign.  IMHO, IDOT does it best by justifying the text of the tab to the side the exit is on.  Why CalTrans can't do this is beyond me if they're so worried about wind loading.

Caltrans does not like that approach because the intent is to retrofit exit numbering (and, where warranted, replacement sign panels) onto existing posts and trusses.  That generally means the new or retrofitted sign has to fit within the same dimensions as the original sign.  In many cases that means shifting the main legend to the side so it avoids the exit tab, or even using a reduced letter size for the main legend.  The Illinois DOT approach (which, as noted upthread, Georgia DOT seems to have abandoned) would work for few if any of these signs because the main legend would conflict with the bottom border for a full-width exit tab.

I disagree with this approach, but I don't see a scenario where Caltrans receives both the funding and the political mandate to adopt a more vanilla MUTCD approach.  I don't think the wind loading concern would disappear unless Caltrans adopted new sign panel designs allowing more flexibility in size and new truss designs with extra capacity to accommodate reasonable variations in sign panel size.  That would leave about 5,000 miles of freeway with obsolete sign support infrastructure, in the charge of an agency whose mindset has been obsessively focused on salvage and reuse since the 1980's.  Plus California in general is full of people who see exit numbering (if they are even aware exits are numbered at all) as a technical change which does not justify spending large sums (possibly in excess of the billion mark) for a start-from-scratch approach.  It is possible to get sign work funded at generous percentages, even up to 100%, by the federal government, but that is a zero-sum game because the total federal funding available to Caltrans is fixed--federal share spent on signs is, generally speaking, federal share that can't be spent on pavement maintenance, capacity upgrades, etc.

That said, I think Caltrans' excuses for not using conventional tabs are at their thinnest for signs installed on new posts in rural areas.  Wind loading is not a pressing constraint for these signs, and indeed conventional tabs have more favorable wind performance than the "strip-style" tabs Caltrans tends to use with laminated-panel signs in these areas.  This is why I say the mentality of treating the sign panel frame as a rigid constraint leads to corner-cutting.  It is also true that a cleanly formatted sign with conventional tab (per MnDOT's usual style) is a drop in the ocean compared to the retrofitted ugliness in urban areas.

[agentsteel53]

an agency whose mindset has been obsessively focused on salvage and reuse

explain what the fuck possessed them to go Nuclear Option on the 110, then!?

[architect77]

What kind of highway are you seeing this on? "EXIT 1 MILE" is indeed the correct legend for unnumbered exits per MUTCD. For numbered exits, "1 MILE" is used because EXIT appears in the exit tab.

Architect77 is complaining about a distinctive approach to freeway signing which GDOT now seems to have abandoned.  This style is distinguished by mixed-case Series D legend at 20" UC/15" LC on overhead signs in lieu of 16" UC/12" LC Series E Modified, full-width exit tabs, and the word "EXIT" appearing redundantly both in the exit tab legend and the distance expression.  Before this style was rolled out sometime in the late 1980's/early 1990's, GDOT used button copy and sign formats were much more conventional with Series E Modified for primary destination legend and no repetition of "EXIT" on the main sign panel.  Indeed, when GDOT introduced exit numbering in the mid-1960's, many guide signs had to be retrofitted with exit tabs and GDOT went to considerable trouble to remove "EXIT" and recenter the distance expression on those signs.

For its current signing, GDOT is retaining the 20" UC/15" LC combination for primary destination legend on overhead guide signs, but is using Series E Modified instead of Series D.  Tabs are independent of the main sign panel and are no longer full-width--judging by the signing plans I have seen, GDOT has settled on a default width of 11'.  Redundant "EXIT" on the main sign panel is no longer used.  GDOT is still using the balanced cantilevers ("elevated-shoulder substitutes" as Architect77 calls them), and I think they are right to continue doing so because this prevents signs from being obscured by large trucks (which they can be if they are mounted on posts and truck traffic is heavy) while also making the sign structures less vulnerable to wind load.

GDOT has let four large signing contracts in the past year, all of which call for signs in the new style.  Sign design sheets so far total 120.  I suspect that GDOT has more signing contracts in the pipeline, but I don't read GDOT STIPs or letting schedules, so I cannot confirm either that this is the case or even that GDOT will be rolling out the new style across its entire freeway network.

When there are only 2 lanes in each direction, a shoulder sign is the standard. When there are 3 lanes, OVERHEAD signage is mandated to provide visibility to all lanes. In other words, the left lane cannot easily see a shoulder mounted sign. Now, Atlanta has some of the widest interstates in the country with usually a MINIMUM of 5 travel lanes. Those left-most lanes cannot easily interpret signage almost 100' over to the right. Their vision is much MORE IMPEDED by high-profile trucks as they attempt to read shoulder mounted signage.

But for me, Georgia's "balanced butterfly" poles are more of engineering back-tracking than anything else. It's like giving up on building the Golden Gate Bridge because an earlier weaker structure collapsed. It's an absurd argument that the 1% of cantilevered signs that have collapsed are reason to give up on a such a simple, primitive engineering feat. You just beef up the trusses like NC is doing. I mean come on, which of the following examples is better providing information to all travel lanes?


This photo came from this site: aaroads

[Henry]

I mean come on, which of the following examples is better providing information to all travel lanes?


This photo came from this site: aaroads

Easily the third photo. Even though the gantry shown there is not a sign bridge because its post exists only on the right side, at least those in the left lanes can see it better than the signs in the first two. Correct me if I'm wrong, but isn't the third photo from that new I-74 freeway?

And speaking of NC, I've seen a few urban freeways there take on the Southern California practice of having guide signs mounted in the median. This has been done in Charlotte and Raleigh; I'm not too sure about the other cities, though.

[mightyace]

The North Carolina sign would definitely qualify for the old topic Cantilevers from hell

When cantilevers get that wide, IMHO, they should be replaced by a sign bridge.  Yes, they obviously work but you end up with absurdly strong posts to support them versus sign bridge posts.

It's an absurd argument that the 1% of cantilevered signs that have collapsed are reason to give up on a such a simple, primitive engineering feat. You just beef up the trusses like NC is doing. I mean come on, which of the following examples is better providing information to all travel lanes?

Well, that's your opinion and your entitled to it.  To me, a 1% failure rate is too high given the consequences of failure.  Do signbridges have a 1% failure rate.  If you can prove they do, I'll keep quiet.  And, single BGS cantilevers are just fine with me.

One of the latest cantilevers to fail was on I-65 south near the Cool Springs Blvd. exit.  Fortunately, no one was hurt when it fell, but the highway was closed for many hours for cleanup causing near gridlock on the south side of Nashville that day.

I may be overreacting to the risk of cantilever failure but I cringe every time I go under one of those monstrosities here in TN.

Architect77 do you live somewhere that has extreme cantilevers?

[national highway 1]

The top two signs should not be used anywhere at all. Series C, and full width exit tabs should not belong on freeway BGSs. And, that style of gantry should not be used either.

[Quillz]

I don't find Series C on BGSs unreadable, do you? I wouldn't use something as narrow as Series B, but I can find C-E(M) very readable.

[national highway 1]

It doesn't look aesthetically good as Series D.

[J N Winkler]

Series D is actually what Georgia DOT uses.  Legibility (expressed as feet of reading distance per inch of letter height) is still measurably inferior to that of Series E Modified.

[Ian]

I've always liked GDOT's use of series D lettering. It's not something you see everyday (unless of course you live in Georgia).

OT: What is the story with Georgia's exit tabs? Are they still using the full width tabs? I've seen photos of some new signs in Atlanta with normal exit tabs, yet the new signs on I-95 have the full width tabs (which I actually enjoy).

[Eth]

New sign installations in Georgia are no longer using full-width exit tabs, plus they have abandoned Series D in favor of E(M).

As a Georgia native, I always preferred that state's use of Series D when I was a kid, but as I got older that changed; I'm happy to see them returning to E(M) now.  Never did like the full-width exit tabs; the first time I left the state I fell in love with the "normal" style, and I'm also happy to see that changing there.

[kharvey10]

IDiOT using series D font for 3di shields.  It looks so condensed that its hard to read.  Add in the Clearview crap and it looks even crappier.  So far they only done it in the Metro East by installing brand new signs last month on 55 between 255 and 270.

[Quillz]

Do you have a picture of an IDiOT 3di shield? CalTRANS uses Series D for 3di, as well, but it sort of works because it's essentially a 1957 design, so you have small Series D numerals on either a 21×18 or 30×25 template.

[kharvey10]

wb 55/70 east of 157

don't have a good usable photo but here is google street view using both clearview and the font for the I-255 shield more consistent on BGS in Missouri.  there is other signs on 55/70 and 64 in the Metro-East that have this font as well.

[Quillz]

Wow, yeah, it's really crammed in there. Forcing in Series D like that probably makes it less legible than just using Series C, which i supposed to be used in 3di shields.

[architect77]

Due to the projected rise in the number of senior drivers in the coming decades, I believe that Georgia and the Federal Highway Administration have concluded that Georgia's narrow font is too hard for them to read. Indeed, Georgia's new signage on the Downtown Connector (75/85) has oversized fat fonts and separate exit tabs.

The new HOT lane signage on I-85 will also return to the more traditional fatter fonts and interestingly will designate the one HOT lane as "EXPRESS" with the other 5 lanes labeled "LOCAL".

[Brandon]

The top two signs should not be used anywhere at all. Series C, and full width exit tabs should not belong on freeway BGSs. And, that style of gantry should not be used either.

Full width exit tabs are just fine as long as the text is properly aligned.  GDOT (along with WSDOT and a certain IDOT district that shall go unnamed but kharvey10 lives in) did not align the text.  I agree about the billboard style of sign.  Those are fugly, and I would be afraid of that gantry failing in high winds.  A full width sign bridge would be better.

See the IDOT District 1 sign below for a proper full width tab.

[national highway 1]

The US 30 shield has a weird shape and looks a bit too small for the BGS.

[Alps]

an agency whose mindset has been obsessively focused on salvage and reuse

explain what the fuck possessed them to go Nuclear Option on the 110, then!?

Is CA 110 referred to only as the Parkway? Since the Clearview demons only invaded I-110, and you say that's THE 110, thought I'd ask.