Is Georgia finally getting it about APL's?

Started by Tom958, August 28, 2016, 07:37:36 AM

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jakeroot

Quote from: cl94 on September 05, 2016, 09:13:23 PM
The New York contingent here certainly has more experience with these than others, but NYSDOT found a way to get rid of the green space without major changes to the design of the sign. NYSTA has/had a couple examples as well.

That sign doesn't have a destination. And don't tell me that it doesn't need one. Not everyone navigates via shields.


Tom958

#26
Quote from: johndoe on September 05, 2016, 07:40:41 PM
I'm no signing expert, but I find it an interesting topic.  Such a weird balance of art and science (or at least that's my view since I don't know the nitty-gritty). 

One of the other challenges I've experienced on projects is "The Overhead Arrow-per-Lane guide sign at the exit shall not be located at or near the theoretical gore." (2E.21.03)  So if you update signs but don't have the money for new trusses, you end up doing pull-through arrows anyway.  I think it will be interesting going forward; will this rule stay?  Many old interchanges have the trusses downstream of the theoretical gore, so when will those start to get updated?

Unless you're in Georgia, in which case you provide new trusses, then put them at or near the physical gore and make a sign that looks just like those rogue APL's where there is no option lane: https://www.aaroads.com/forum/index.php?topic=204.msg2118728#msg2118728 . Here there are three APL signs, two option lane splits, and a grand total of one diverging arrow. In fairness, it may be that the APL's were placed downstream of the existing signs so as not to obstruct them while the new signs were being erected. A case could've been made for going back to conventional signage there, as implied in your old pal Section 2E-8 of the MUTCD, but... no.

Then there's this, which is in its own category: https://www.aaroads.com/forum/index.php?topic=87.msg2142971#msg2142971 .

Of course, readers of this thread focused on the screwups, but I posted it because I was actually encouraged by what appears to be better comprehension of sign design principles by GDOT. There's still a ways to go, though.

Quote from: johndoeThat brings me to my LEAST favorite situation; where an option lane is signed as exit only (since technically the lane exists at the point of the truss).  We talked about that a bit in this thread I started a while back:  https://www.aaroads.com/forum/index.php?topic=16467
I STILL can't fathom how an OPTION lane is supposed to be signed as exit ONLY.

You and I both. Too bad that this, which I photographed myself in July, is so grossly against the rules.   :rolleyes:

What's really weird, at least here in Georgia, is that there were a few new generation Series E(M) signs that retained the old configuration with one white-on-green arrow and one black-on-yellow. Then, years later, came a tsunami of 2009 MUTCD-compliant monsters. It's as though GDOT had experienced a coup de etat and the forces of suck had triumphed.

However, when that happened, there was a round of signage replacements which also involved replacement of the gantries. Guess what: the new gantries were located just behind the old ones, well upstream of the theoretical gore, and in direct conflict with the MUTCD. In fact, they're actually located correctly for APL's! Question: What's one notch worse that a black-on-yellow arrow for an option lane? Answer: A black-on-yellow arrow for an option lane that's actually over the mainline! And we have them all over the place here.

cl94

That sign doesn't need a destination. The Thruway is in a mile and the freeway has a stub ending immediately afterwards. Every non-local would be getting off at the Thruway.

Want one with a destination? Fine. Here's another.

My criticisms come from my dealings with the non-engineering public. Space is good for perception, especially from a distance, while closely-spaced lettering and figures confuses people and increases the time required to understand the sign. If the California-style sign was superior or equal, more states would have likely adopted it due to its smaller surface area (and thus lower cost). Want an APL that has a smaller amount of blank space? Cut out the blank space and mount the sign like the New York examples.
Please note: All posts represent my personal opinions and do not represent those of my employer or any of its partner agencies.

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jakeroot

Quote from: cl94 on September 05, 2016, 10:12:55 PM
That sign doesn't need a destination. The Thruway is in a mile and the freeway has a stub ending immediately afterwards. Every non-local would be getting off at the Thruway.

They could at least put "Thruway", so you don't have to read the tiny shield text.

Quote from: cl94 on September 05, 2016, 10:12:55 PM
My criticisms come from my dealings with the non-engineering public. Space is good for perception, especially from a distance, while closely-spaced lettering and figures confuses people and increases the time required to understand the sign. If the California-style sign was superior or equal, more states would have likely adopted it due to its smaller surface area (and thus lower cost). Want an APL that has a smaller amount of blank space? Cut out the blank space and mount the sign like the New York examples.

Why does everyone keep bringing up California? I already said that I don't model my signs after CalTrans. I just minimize sign heights in order to minimize green space, so as to reduce the sign's area. I don't think there's any DOT out there that intentionally uses tall signage just for fun.

My problem with the cut-out New York signs is that they bring too much of the background into the sign. When I'm looking for directions, I'm looking for the big green sign in the distance. The less visible green, IMO, the worse off the sign. Don't get me wrong -- both signs are plenty visible. I just think the normal rectangular signage is superior because it's, more or less, easier to spot.

Just out of curiosity: what's the cost for cutting off all that extra signage? Is that even possible with states that use increment panel signs? I'm more familiar with extruded signs here in Washington, but I know that most states use increment panel signs (I believe the extruded panels are what allows New York to use rounded corners like Virginia, Florida, and North Carolina).

cl94

Quote from: jakeroot on September 05, 2016, 11:22:29 PM
Why does everyone keep bringing up California? I already said that I don't model my signs after CalTrans. I just minimize sign heights in order to minimize green space, so as to reduce the sign's area. I don't think there's any DOT out there that intentionally uses tall signage just for fun.

My problem with the cut-out New York signs is that they bring too much of the background into the sign. When I'm looking for directions, I'm looking for the big green sign in the distance. The less visible green, IMO, the worse off the sign. Don't get me wrong -- both signs are plenty visible. I just think the normal rectangular signage is superior because it's, more or less, easier to spot.

Just out of curiosity: what's the cost for cutting off all that extra signage? Is that even possible with states that use increment panel signs? I'm more familiar with extruded signs here in Washington, but I know that most states use increment panel signs (I believe the extruded panels are what allows New York to use rounded corners like Virginia, Florida, and North Carolina).

We mentioned California because they're the only US state with signs like that outside of confined spaces. There are certainly problems with the cut-outs as well, but that addresses the legibility issue old people complain about as stuff appears less compact (and I hear that quite a bit for all sorts of applications, not only signs). Honestly, I have no problem with compact signs myself, but I know what the public will complain about.

Increment panels are typically where the rounded corners are found. Extruded panels have the ribs on the back. Major states with increment panels are, as you mentioned below, New York, Virginia, Florida and North Carolina. Of course, there's one extruded sign in Ontario with rounded corners on 401 that another user and I were actually talking about earlier today. That one must have been a PITA to make. Yeah, New York is able to get away with the cutouts because of how the signs are made. For the unitiated: extruded signs are one giant sheet, while incrementals are a bunch of tiny pieces. A cutout, in the case of an incremental sign, actually reduces assembly time as well as cost.
Please note: All posts represent my personal opinions and do not represent those of my employer or any of its partner agencies.

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myosh_tino

Quote from: jakeroot on September 05, 2016, 09:02:32 PM
Quote from: compdude787 on September 05, 2016, 08:59:23 PM
I know this is sort of going off on a tangent, but why is it that California makes its signs shorter than other states?

Wind loading. I don't know the exact specifics as to why that's the case. myosh_tino -- our resident California expert -- would know for sure why. It has to do with the design of the sign trusses, though.

I don't know for sure but I believe wind-loading is definitely a factor now.  I am not entirely sure what the justification was back in the day for the 120" height limit other than pure aesthetics combined with the policy that all signs on the same structure (truss or overpass) be the same height.  Perhaps forum user jrouse, a Caltrans employee, can shed some light on these policy decisions.

What I do know is AASHTO recently changed the wind-loading standards making all older trusses no longer in compliance.  They can still be used in the field but the new signs cannot be larger than the sign they're replacing.  Furthermore, the new trusses have been designed to accommodate external exit tabs but because so many of the older trusses are still in use, the spec for mounting the tabs has not been developed yet.

Now I'm sure the simple argument would be to replace all the old trusses with new ones however, due to the size of California's freeway system and sheer number of these old trusses still in service, doing a wholesale replacement would be very, very expensive.

Now with ALL of that said, new signs for the I-680 Express Lane from Dublin north to Walnut Creek appear to be much taller than the 120" maximum.  I also seem to recall someone here posting a photo of a significantly taller overhead sign in southern California.
Quote from: golden eagle
If I owned a dam and decided to donate it to charity, would I be giving a dam? I'm sure that might be a first because no one really gives a dam.

vdeane

One would think California would make the spec for external exit tabs (or just steal one from another state; why reinvent the wheel?) so that at least the signs on the new trusses could have proper exit tabs.  It will probably be 50 years before the old trusses are gone, at which point the standards will have changed again, and CA will be in the exact same situation they are in now.

And yes, cramped signs are quite difficult to read.
Please note: All comments here represent my own personal opinion and do not reflect the official position of NYSDOT or its affiliates.

AsphaltPlanet

Quote from: myosh_tino on September 06, 2016, 02:55:55 AM
Quote from: jakeroot on September 05, 2016, 09:02:32 PM
Quote from: compdude787 on September 05, 2016, 08:59:23 PM
I know this is sort of going off on a tangent, but why is it that California makes its signs shorter than other states?

Wind loading. I don't know the exact specifics as to why that's the case. myosh_tino -- our resident California expert -- would know for sure why. It has to do with the design of the sign trusses, though.

I don't know for sure but I believe wind-loading is definitely a factor now.  I am not entirely sure what the justification was back in the day for the 120" height limit other than pure aesthetics combined with the policy that all signs on the same structure (truss or overpass) be the same height.  Perhaps forum user jrouse, a Caltrans employee, can shed some light on these policy decisions.

What I do know is AASHTO recently changed the wind-loading standards making all older trusses no longer in compliance.  They can still be used in the field but the new signs cannot be larger than the sign they're replacing.  Furthermore, the new trusses have been designed to accommodate external exit tabs but because so many of the older trusses are still in use, the spec for mounting the tabs has not been developed yet.

Now I'm sure the simple argument would be to replace all the old trusses with new ones however, due to the size of California's freeway system and sheer number of these old trusses still in service, doing a wholesale replacement would be very, very expensive.

Now with ALL of that said, new signs for the I-680 Express Lane from Dublin north to Walnut Creek appear to be much taller than the 120" maximum.  I also seem to recall someone here posting a photo of a significantly taller overhead sign in southern California.

I could see wind loading be a factor on the truss design that California uses.  But this begs the question of course, if wind loading is such a problem with the truss design that it uses (and seemingly has used forever), why does it use that truss design?
AsphaltPlanet.ca  Youtube -- Opinions expressed reflect the viewpoints of others.

cl94

Quote from: AsphaltPlanet on September 06, 2016, 01:17:01 PM
Quote from: myosh_tino on September 06, 2016, 02:55:55 AM
Quote from: jakeroot on September 05, 2016, 09:02:32 PM
Quote from: compdude787 on September 05, 2016, 08:59:23 PM
I know this is sort of going off on a tangent, but why is it that California makes its signs shorter than other states?

Wind loading. I don't know the exact specifics as to why that's the case. myosh_tino -- our resident California expert -- would know for sure why. It has to do with the design of the sign trusses, though.

I don't know for sure but I believe wind-loading is definitely a factor now.  I am not entirely sure what the justification was back in the day for the 120" height limit other than pure aesthetics combined with the policy that all signs on the same structure (truss or overpass) be the same height.  Perhaps forum user jrouse, a Caltrans employee, can shed some light on these policy decisions.

What I do know is AASHTO recently changed the wind-loading standards making all older trusses no longer in compliance.  They can still be used in the field but the new signs cannot be larger than the sign they're replacing.  Furthermore, the new trusses have been designed to accommodate external exit tabs but because so many of the older trusses are still in use, the spec for mounting the tabs has not been developed yet.

Now I'm sure the simple argument would be to replace all the old trusses with new ones however, due to the size of California's freeway system and sheer number of these old trusses still in service, doing a wholesale replacement would be very, very expensive.

Now with ALL of that said, new signs for the I-680 Express Lane from Dublin north to Walnut Creek appear to be much taller than the 120" maximum.  I also seem to recall someone here posting a photo of a significantly taller overhead sign in southern California.

I could see wind loading be a factor on the truss design that California uses.  But this begs the question of course, if wind loading is such a problem with the truss design that it uses (and seemingly has used forever), why does it use that truss design?

I have wondered the same thing. Buffalo has some of the same wind issues (visit during the winter and you'll see what I mean) and they do large signs just fine. How? Take a look at the back of this APL. Lateral bracing provides sign stability. 60+ mph gusts are quite common in the winter and this sign could probably take well over 120.
Please note: All posts represent my personal opinions and do not represent those of my employer or any of its partner agencies.

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myosh_tino

#34
Quote from: vdeane on September 06, 2016, 01:02:17 PM
One would think California would make the spec for external exit tabs (or just steal one from another state; why reinvent the wheel?) so that at least the signs on the new trusses could have proper exit tabs.  It will probably be 50 years before the old trusses are gone, at which point the standards will have changed again, and CA will be in the exact same situation they are in now.

Except there's one problem.

Quote from: jrouse on August 09, 2015, 12:58:30 PM
The reason why the exit number tabs have been placed in the main sign panel over the years is because Caltrans does not have a standard detail for mounting sign tabs on top of the truss.  This is because many of the sign trusses on the system don't meet the current AASHTO wind load standards, and so Caltrans didn't want to put together a detail that would further violate the standards.  The sign trusses can continue to be used but the sign panel area sizes cannot be increased.  Even though the current sign truss designs do meet the AASHTO wind load standards and are capable of handling tabs, Caltrans still has not developed a standard detail for mounting tabs.

Based on this information from jrouse, the standard detail for mounting an external exit tab can't be used on the older trusses which I suspect is why it hasn't been developed yet.  I can only assume that you won't see external exit tabs until a vast majority of the old trusses are taken out of service.

In a sense, I wish Caltrans would get this done (using external exit tabs) sooner rather than later because I think that will put a stop to all of the funky sign layouts.
Quote from: golden eagle
If I owned a dam and decided to donate it to charity, would I be giving a dam? I'm sure that might be a first because no one really gives a dam.

vdeane

#35
But why can't CalTrans use a hypothetical external tab detail on the NEW trusses and continue using bizarro signs on the old trusses?  At least get the ball rolling.  As it is now, 50 years in the future when the last old truss is taken down, CalTrans will probably just continue using internal tabs because "that's how we've always done it".

It's not as if their signs follow anything even remotely resembling a standard, so there's no possibility of confusing anyone.  Honestly, I don't know why they even bother to have a MUTCD, at least for guide signs, since the current method is just "cram the details in wherever they will fit".
Please note: All comments here represent my own personal opinion and do not reflect the official position of NYSDOT or its affiliates.

machias

Quote from: vdeane on September 06, 2016, 05:38:50 PM
But why can't CalTrans use a hypothetical external tab detail on the NEW trusses and continue using bizarro signs on the old trusses?  At least get the ball rolling.  As it is now, 50 years in the future when the last old truss is taken down, CalTrans will probably just continue using internal tabs because "that's how we've always done it".

It's not as if their signs follow anything even remotely resembling a standard, so there's no possibility of confusing anyone.  Honestly, I don't know why they even bother to have a MUTCD, at least for guide signs, since the current method is just "cram the details in wherever they will fit".

Wait a second, Caltrans used to have panels with separate exit tabs on overhead signs somewhere east of Los Angeles. I actually liked the look of those signs because they looked "normal" with their centered tabs. Did they forget how to do those?

myosh_tino

Quote from: upstatenyroads on September 06, 2016, 10:37:50 PM
Quote from: vdeane on September 06, 2016, 05:38:50 PM
But why can't CalTrans use a hypothetical external tab detail on the NEW trusses and continue using bizarro signs on the old trusses?  At least get the ball rolling.  As it is now, 50 years in the future when the last old truss is taken down, CalTrans will probably just continue using internal tabs because "that's how we've always done it".

It's not as if their signs follow anything even remotely resembling a standard, so there's no possibility of confusing anyone.  Honestly, I don't know why they even bother to have a MUTCD, at least for guide signs, since the current method is just "cram the details in wherever they will fit".

Wait a second, Caltrans used to have panels with separate exit tabs on overhead signs somewhere east of Los Angeles. I actually liked the look of those signs because they looked "normal" with their centered tabs. Did they forget how to do those?

I believe jrouse said he does have copies of the old specification but I figure they're no good because...

1. The truss design has changed over the years
2. It no longer adheres to the new wind-loading standards put forth by AASHTO
3. Exit tabs can't be centered per the current MUTCD.

With all that said, I also liked how those signs looked.  It kind of reminds me of Oregon's BGSes.
Quote from: golden eagle
If I owned a dam and decided to donate it to charity, would I be giving a dam? I'm sure that might be a first because no one really gives a dam.

vdeane

Around here, exit tabs are mounted to signs, not trusses.  NYSDOT just extends the sign support upwards and mounts the tab to that.  I can see how changing from centered tabs could create spec issues, though.
Please note: All comments here represent my own personal opinion and do not reflect the official position of NYSDOT or its affiliates.

Scott5114

Quote from: jakeroot on September 05, 2016, 08:59:43 PM
Oh, it's too cramped? How do you guys figure that? Is there some sort of "cramp" index that the MUTCD developed? If there is, I'd be happy to redesign any sign to meet those requirements.

§2E.14¶04 (first sentence), §2E.15
uncontrollable freak sardine salad chef

J N Winkler

Quote from: jakeroot on August 29, 2016, 01:15:13 PMThe way I see it, however, is that Georgia is being put between a rock and a hard place: The MUTCD requires APLs when there's an option lane, but there are many junctions all across Georgia where there are several option lanes in a row, and they must all be, somehow, signed on the same sign.

Actually, that is not quite true.  The MUTCD requires OAPLs if and only if (1) the major route does a TOTSO and (2) there is an option lane feeding into the movement in question.  For other interchanges with an option lane, the current edition of MUTCD allows diagrammatics not to be used, in which case the option lane must be "hidden" until the gore.

I frankly think GDOT would be much better off sticking to the original approach (which, if memory serves, called for hiding the option lanes) for the areas along I-285 with option lanes in rapid-fire succession.
"It is necessary to spend a hundred lire now to save a thousand lire later."--Piero Puricelli, explaining the need for a first-class road system to Benito Mussolini

roadfro

Quote from: J N Winkler on September 11, 2016, 08:50:05 AM
Quote from: jakeroot on August 29, 2016, 01:15:13 PMThe way I see it, however, is that Georgia is being put between a rock and a hard place: The MUTCD requires APLs when there's an option lane, but there are many junctions all across Georgia where there are several option lanes in a row, and they must all be, somehow, signed on the same sign.

Actually, that is not quite true.  The MUTCD requires OAPLs if and only if (1) the major route does a TOTSO and (2) there is an option lane feeding into the movement in question.  For other interchanges with an option lane, the current edition of MUTCD allows diagrammatics not to be used, in which case the option lane must be "hidden" until the gore.

I think your statement #1, regarding TOTSO, is incorrect:

2009 MUTCD Section 2E.20 p2:
QuoteStandard:
02   "On freeways and expressways, either the Overhead Arrow-per-Lane or Diagrammatic guide sign designs as provided in Sections 2E.21 and 2E.22 shall be used for all multi-lane exits at major interchanges (see Section 2E.32) that have an optional exit lane that also carries the through route (see Figures 2E-4, 2E-5, 2E-8, and 2E-9) and for all splits that include an option lane (see Figures 2E-6 and 2E-10). Overhead Arrow-per-Lane or Diagrammatic guide signs shall not be used on freeways and expressways for any other types of exits or splits, including single-lane exits and splits that do not have an option lane."
Roadfro - AARoads Pacific Southwest moderator since 2010, Nevada roadgeek since 1983.

jakeroot

Quote from: Scott5114 on September 10, 2016, 06:51:33 AM
Quote from: jakeroot on September 05, 2016, 08:59:43 PM
Oh, it's too cramped? How do you guys figure that? Is there some sort of "cramp" index that the MUTCD developed? If there is, I'd be happy to redesign any sign to meet those requirements.

§2E.14¶04 (first sentence), §2E.15

Admittedly, I'm having a hard time making sense of that page. If someone wants to take one of my signs and size it up to the standards listed under Chapter 2E, that'd be awesome. Myosh_tino has already scrutinized my previous designs to a great degree, so rest assured that the legends you see are the correct size (the issue here is the green space).

Scott5114

Quote from: jakeroot on September 11, 2016, 06:25:34 PM
Quote from: Scott5114 on September 10, 2016, 06:51:33 AM
Quote from: jakeroot on September 05, 2016, 08:59:43 PM
Oh, it's too cramped? How do you guys figure that? Is there some sort of "cramp" index that the MUTCD developed? If there is, I'd be happy to redesign any sign to meet those requirements.

§2E.14¶04 (first sentence), §2E.15

Admittedly, I'm having a hard time making sense of that page. If someone wants to take one of my signs and size it up to the standards listed under Chapter 2E, that'd be awesome. Myosh_tino has already scrutinized my previous designs to a great degree, so rest assured that the legends you see are the correct size (the issue here is the green space).

§2E.14¶04 says that the legend must be dimensioned out first and then the panel sized to fit the legend. Caltrans' sign height standard is a clear violation of this section. Following the MUTCD, if the message size + required margins dictates that a sign panel must exceed the theoretical maximum, that is the size the panel must be. It also implies that states that make multiple BGSes on a gantry the same size for uniformity are in the wrong.

§2E.15 provides guidelines for margins and interline spacing. If the upper case letters in a line of legend are x inches tall, the lines of text should be 0.75x inches apart, and the block of text should have x inches of free space on all sides. So if you had a line of text that had 12" capital letters, each line should be 9" apart and have 12" of free space to the left and right, as well as above the top line and below the bottom line.
uncontrollable freak sardine salad chef

Tom958

Quote from: roadfro on September 11, 2016, 04:49:10 PM
Quote from: J N Winkler on September 11, 2016, 08:50:05 AM
Quote from: jakeroot on August 29, 2016, 01:15:13 PMThe way I see it, however, is that Georgia is being put between a rock and a hard place: The MUTCD requires APLs when there's an option lane, but there are many junctions all across Georgia where there are several option lanes in a row, and they must all be, somehow, signed on the same sign.

Actually, that is not quite true.  The MUTCD requires OAPLs if and only if (1) the major route does a TOTSO and (2) there is an option lane feeding into the movement in question.  For other interchanges with an option lane, the current edition of MUTCD allows diagrammatics not to be used, in which case the option lane must be "hidden" until the gore.


I think your statement #1, regarding TOTSO, is incorrect:

2009 MUTCD Section 2E.20 p2:
QuoteStandard:
02   "On freeways and expressways, either the Overhead Arrow-per-Lane or Diagrammatic guide sign designs as provided in Sections 2E.21 and 2E.22 shall be used for all multi-lane exits at major interchanges (see Section 2E.32) that have an optional exit lane that also carries the through route (see Figures 2E-4, 2E-5, 2E-8, and 2E-9) and for all splits that include an option lane (see Figures 2E-6 and 2E-10). Overhead Arrow-per-Lane or Diagrammatic guide signs shall not be used on freeways and expressways for any other types of exits or splits, including single-lane exits and splits that do not have an option lane."


It appears that there's a bit of room for discretion as to what constitutes a major interchange. Getting back in the general direction of the original topic, there's this new APL for a service interchange. Without looking, I'm certain that Barrett Parkway is a principal arterial, though I think it's unlikely that either a large number or a high proportion of drivers who would consider taking that exit are unfamiliar with the area. The current Streetview shows both the new APL and the previous conventional sign.

J N Winkler

Quote from: roadfro on September 11, 2016, 04:49:10 PMI think your statement #1, regarding TOTSO, is incorrect.

I will concede error to the extent that I neglected to mention splits.  But actually the MUTCD section you quoted is what I rely on when I say that OAPLs are required only at splits with option lanes and multilane exits where the major route follows the exiting movement.  Looking at the relevant provision more closely:

Quote from: 2009 MUTCD Section 2E.20On freeways and expressways, either the Overhead Arrow-per-Lane or Diagrammatic guide sign designs as provided in Sections 2E.21 and 2E.22 shall be used for all multi-lane exits at major interchanges (see Section 2E.32) that have an optional exit lane that also carries the through route (see Figures 2E-4, 2E-5, 2E-8, and 2E-9) and for all splits that include an option lane (see Figures 2E-6 and 2E-10).

When standards for signing at major interchanges were being refined in the mid-1970's according to the positive guidance paradigm, a distinction was drawn among three kinds of movement that were considered to have different characteristics in terms of driver expectancy.  These were:

*  Splits:  the road ahead divides into two, with each side belonging to one route and neither side being obviously more important than the other.  (The traditional MUTCD illustration for this situation is based on the then I-495/I-70S, now I-495/I-270 divide on the Capital Beltway in suburban Maryland, and the traditional stippled-arrow diagrammatic solution for this situation has two arrows moving out to the side.)

*  Multilane exits where major route follows the mainline:  in this case the mainline is clearly differentiated from the exiting movement by more generous geometry, higher lane count, etc.  The left-exit version of this presents more difficulty to the driver than the right-exit version, but in neither case is a driver wishing to follow the major route obliged to prepare to exit.

*  Multilane exits where major route follows the exiting movement:  again, in this case, the mainline is clearly favored by geometry, lane count, etc. but a driver following the major route must prepare to exit.  (This is the TOTSO case.)

Stippled-arrow diagrammatics were introduced in the 1978 MUTCD as the result of a major diagrammatic study (the Mast & Kolsrud study) which was in progress when the 1971 MUTCD was being developed.  The 1971 edition was the last to permit cloverleaf diagrammatics, which Mast & Kolsrud showed to be ineffective, and MUTCD editions between 1978 and 2003 (inclusive) adopted a deliberately permissive policy with regard to stippled-arrow diagrammatics:  they could be used with or without option lanes, they could be used (standard designs were provided) in any of the three situations described above, and they could be used with simple one-lane exits (lane dropped or not) if the exit was on the left or the interchange coincided with a bend in the mainline.  In none of these cases was the use of a diagrammatic required by a shall condition, and a few state DOTs (like Arizona DOT) never used stippled-arrow diagrammatics.

The 2009 edition, in contrast, is much more restrictive.  Diagrammatics of either kind (stippled-arrow or OAPL) can be used only when there is an option lane.  The quoted section above also mentions the new shall conditions for the use of diagrammatics of either kind:  splits (first case described above), and multilane exits where the major route follows the exit (third case described above).  The figures referred to in the quoted section do show cases corresponding to the second case described above (major route follows the mainline), but since through route is not explicitly defined, a state DOT is safe in not providing OAPLs unless the major route actually follows the exiting movement.  This is similar to the way in which MUTCD editions before 2003 (inclusive) permitted the non-Lunenfeld & Alexander method for signing lane drops with option lane (one white arrow on green, one black arrow on yellow) by never explicitly specifying what a multilane exit was.  The figures cited therefore show a mix of required (OAPLs or stippled-arrow diagrammatics must be used) and permissive (OAPLs or stippled-arrow diagrammatics may be used) cases.
"It is necessary to spend a hundred lire now to save a thousand lire later."--Piero Puricelli, explaining the need for a first-class road system to Benito Mussolini

Tom958

They fixed it, presumably when they added SunTrust Park to the sign. I am agog.



Previously:

mrsman

I don't like the new result.  It should be clear that the third lane can go to either 75 or 285.  I suggest maybe a Y shaped arrow with both arrows facing nearly perfectly up but both emanating from a single stem, so that it is clear that the third lane can go to two directions.

Eth

Honestly, given what's actually available in the MUTCD here, that's probably about as good as you're gonna get. OAPL, Minnesota-style (sort of).

Tom958

#49
Quote from: Tom958 on August 28, 2016, 08:11:54 AMAnd, at the split. As you'll soon see, there's an APL-appropriate exit only about 3/4 mile beyond here, and a case could've been made for using an APL here to give sufficient notice, with a conventional sign for 575. Perhaps it was thought that the curvature of the roadways here would make that too confusing.



Today it came to my attention that this installation has been changed. Now I want to know if the APL beyond is still there. I'd guess so, but apparently anything can happen. EDIT: Yes, it is.



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