California Observations

[blawp]

WTF was wrong with puting the exit tab on top of the sign?

What's wrong with it the way it is?

It's called the MUTCd.

California has their own marked up version of the MUTCD, and this sign is compliant.

[Alps]

WTF was wrong with puting the exit tab on top of the sign?

What's wrong with it the way it is?

It's called the MUTCd.

California has their own marked up version of the MUTCD, and this sign is compliant.

CA has so many people, it gets to bend things mercilessly. The exit tabs inside the sign should never have been allowed on any new sign, only as a temporary fix until signs are replaced.

[myosh_tino]

As I have a said a number of times, California's reasoning for putting the exit tab inside the sign panel was due to existing wind-loading requirements that precluded Caltrans from using "regular" tabs.  Simply put, the sign structures (sign bridges, mounting hardware, etc) cannot handle external tabs as currently designed.  I read somewhere that Caltrans has developed or updated some of this hardware to accommodate external tabs but I suspect existing hardware is going to be used until the supply has been exhausted.  Perhaps, jrouse can clarify this issue as he is a Caltrans employee.

I'd suggest visiting Daniel Faigin's cahighways.org site for a more indepth explanation on this issue.

[Brandon]

As I have a said a number of times, California's reasoning for putting the exit tab inside the sign panel was due to existing wind-loading requirements that precluded Caltrans from using "regular" tabs.  Simply put, the sign structures (sign bridges, mounting hardware, etc) cannot handle external tabs as currently designed.  I read somewhere that Caltrans has developed or updated some of this hardware to accommodate external tabs but I suspect existing hardware is going to be used until the supply has been exhausted.  Perhaps, jrouse can clarify this issue as he is a Caltrans employee.

I'd suggest visiting Daniel Faigin's cahighways.org site for a more indepth explanation on this issue.

I'm convinced it's a CalTrans cop-out.  Nevada uses the same sign bridges with external tabs, and I suspect, similar wind loading stresses.

[myosh_tino]

I'm convinced it's a CalTrans cop-out.  Nevada uses the same sign bridges with external tabs, and I suspect, similar wind loading stresses.

But IIRC, the method of fabricating sign panels is different between Nevada and California and it's also possible the mounting hardware is different.  While these differences are not visually apparent, they could be the reason why California is doing what it's doing.

[Alps]

It's incorrect. I don't know how they do their structure design, but if the sign were 18" shorter, the exit tab would cause less wind loading than existing. A lot of these signs have greenouts and non-MUTCD compliant destinations that can be eliminated. Exit tabs should be the standard, period.

[myosh_tino]

It's incorrect. I don't know how they do their structure design, but if the sign were 18" shorter, the exit tab would cause less wind loading than existing. A lot of these signs have greenouts and non-MUTCD compliant destinations that can be eliminated. Exit tabs should be the standard, period.

Then why aren't you ragging on Washington's full width tabs?  Or Oregon's centered tabs?

If the way California is trying to add exit numbers annoys so many out-of-staters, then maybe Caltrans should abandon exit numbering all together. I know that won't happen but frankly I don't think a majority of Californians care about exit numbering.

Finally, remember that the FHWA signed off on California's 2012 MUTCD which includes provisions for both internal and external tabs.

[Alps]

It's incorrect. I don't know how they do their structure design, but if the sign were 18" shorter, the exit tab would cause less wind loading than existing. A lot of these signs have greenouts and non-MUTCD compliant destinations that can be eliminated. Exit tabs should be the standard, period.

Then why aren't you ragging on Washington's full width tabs?  Or Oregon's centered tabs?

If the way California is trying to add exit numbers annoys so many out-of-staters, then maybe Caltrans should abandon exit numbering all together. I know that won't happen but frankly I don't think a majority of Californians care about exit numbering.

Finally, remember that the FHWA signed off on California's 2012 MUTCD which includes provisions for both internal and external tabs.

Damn, dude, you think because I don't name every single instance that I support them all? Shoddy arguing skills, there. I know FHWA signed off on it, but I think it's because of California's significant influence. They tend to get their way because they're a) populous and b) pioneers when it comes to standards, even though many of the standards have been improved by the other 49 states since.

[blawp]

The internal tabs look cleaner, and maintain the even sign height requirements Caltrans has always had.

[AsphaltPlanet]

Damn, dude, you think because I don't name every single instance that I support them all? Shoddy arguing skills, there. I know FHWA signed off on it, but I think it's because of California's significant influence. They tend to get their way because they're a) populous and b) pioneers when it comes to standards, even though many of the standards have been improved by the other 49 states since.

Either that, or you know, because of the fact that the position of an exit tab within a freeway sign really isn't all that important.

[roadfro]

I'm convinced it's a CalTrans cop-out.  Nevada uses the same sign bridges with external tabs, and I suspect, similar wind loading stresses.

But IIRC, the method of fabricating sign panels is different between Nevada and California and it's also possible the mounting hardware is different.  While these differences are not visually apparent, they could be the reason why California is doing what it's doing.

I kinda understand CalTrans' wind loading explanation for certain types of sign structures, especially older assemblies such as monotubes and box beam sign supports. But the open truss designs which are visually similar to Nevada's standard overhead sign structure...I'm sorry, but I just don't think their wind loading explanation holds water with that kind of reinforced truss. I'd love to see some calcs on it though.

Granted, the sign fabrication and mounting is different between the two states. But NDOT often has larger panel signs that extend above the top of the truss by a foot or two, then the exit tab on top of that... it seems very odd that CalTrans would have such different standards.


But you can also count me in the camp that doesn't mind too terribly California's internal exit number tabs... I am just happy to see exit numbers at all...

[J N Winkler]

I know FHWA signed off on it, but I think it's because of California's significant influence. They tend to get their way because they're a) populous and b) pioneers when it comes to standards, even though many of the standards have been improved by the other 49 states since.

I don't think it is influence as such.  FHWA has an interest in securing some degree of local buy-in to what are supposed to be uniform national standards.  Also, California has so much invested in sign panel designs (such as formed panels in removable sign panel frames) which make exit tabs difficult to do that if FHWA stuck to its guns and insisted that exit numbering had to be carried out solely by means of tabs, Caltrans could plausibly argue that FHWA was inflicting high costs on California for no added benefit, which would attract Congressional action.  By bending the rules to accept the California MUTCD as is, FHWA saves both itself and Caltrans from joining a battle neither agency can win.

[Brandon]

The internal tabs look cleaner, and maintain the even sign height requirements Caltrans has always had.

They could do the same thing with full-width Illinois-style tabs (and IDOT District 1 does exactly that - having the same height signs across the gantry).

[Alps]

The internal tabs look cleaner, and maintain the even sign height requirements Caltrans has always had.

Either that, or you know, because of the fact that the position of an exit tab within a freeway sign really isn't all that important.

But it IS important. The whole idea is to stick out so that it's noticeable when you're looking for your exit. It's a lot harder to see when it blends in with the rest of the sign. If that weren't the case, the MUTCD would allow it within the sign. I think it looks a LOT cleaner to keep it outside of the sign body, and let the sign be symmetrically balanced.

[AsphaltPlanet]

But it IS important. The whole idea is to stick out so that it's noticeable when you're looking for your exit. It's a lot harder to see when it blends in with the rest of the sign. If that weren't the case, the MUTCD would allow it within the sign. I think it looks a LOT cleaner to keep it outside of the sign body, and let the sign be symmetrically balanced.

Can you cite the human factors study that backs up your position?  Or are you just supplanting your opinion for the truth.  Quebec uses integrated exit tabs for all of its freeway guide signage, and to my knowledge, Quebecers aren't inadvertently driving into fleuve Saint Laurent out of exit number confusion.

[Quillz]

But it IS important. The whole idea is to stick out so that it's noticeable when you're looking for your exit. It's a lot harder to see when it blends in with the rest of the sign. If that weren't the case, the MUTCD would allow it within the sign. I think it looks a LOT cleaner to keep it outside of the sign body, and let the sign be symmetrically balanced.

Can you cite the human factors study that backs up your position?  Or are you just supplanting your opinion for the truth.  Quebec uses integrated exit tabs for all of its freeway guide signage, and to my knowledge, Quebecers aren't inadvertently driving into fleuve Saint Laurent out of exit number confusion.

I really like quebec's integrated exit tabs. They have an interesting yellow cutout design.

[Alps]

But it IS important. The whole idea is to stick out so that it's noticeable when you're looking for your exit. It's a lot harder to see when it blends in with the rest of the sign. If that weren't the case, the MUTCD would allow it within the sign. I think it looks a LOT cleaner to keep it outside of the sign body, and let the sign be symmetrically balanced.

Can you cite the human factors study that backs up your position?  Or are you just supplanting your opinion for the truth.  Quebec uses integrated exit tabs for all of its freeway guide signage, and to my knowledge, Quebecers aren't inadvertently driving into fleuve Saint Laurent out of exit number confusion.

I really like quebec's integrated exit tabs. They have an interesting yellow cutout design.

And if our exit tabs were similarly a different color, I wouldn't have a problem. Green on green just doesn't contrast. Mr. Asphalt Planet, to accuse me of being subjective implies that your opinion is objective, which it isn't. At least I'm informed by being a traffic engineer in addition to an enthusiast.

[AsphaltPlanet]

And if our exit tabs were similarly a different color, I wouldn't have a problem. Green on green just doesn't contrast. Mr. Asphalt Planet, to accuse me of being subjective implies that your opinion is objective, which it isn't. At least I'm informed by being a traffic engineer in addition to an enthusiast.

I asked you to cite your position to verify its validity.  Given that you didn't it's probably fair to infer you can't.

[Alps]

And if our exit tabs were similarly a different color, I wouldn't have a problem. Green on green just doesn't contrast. Mr. Asphalt Planet, to accuse me of being subjective implies that your opinion is objective, which it isn't. At least I'm informed by being a traffic engineer in addition to an enthusiast.

I asked you to cite your position to verify its validity.  Given that you didn't it's probably fair to infer you can't.

And I said I'm an engineer, so I'm using engineering judgment and experience. That's a perfectly valid position to hold.

[Interstate Trav]

It's incorrect. I don't know how they do their structure design, but if the sign were 18" shorter, the exit tab would cause less wind loading than existing. A lot of these signs have greenouts and non-MUTCD compliant destinations that can be eliminated. Exit tabs should be the standard, period.

Then why aren't you ragging on Washington's full width tabs?  Or Oregon's centered tabs?

If the way California is trying to add exit numbers annoys so many out-of-staters, then maybe Caltrans should abandon exit numbering all together. I know that won't happen but frankly I don't think a majority of Californians care about exit numbering.

Finally, remember that the FHWA signed off on California's 2012 MUTCD which includes provisions for both internal and external tabs.

So true, as a California person I got used to no exit numbers.  Personally I could care less either way.  I always thought it was wierd to drive into other states and see exit numbers.  I know in California it used to be we refer to the exit by the road name, not number.

I'm kinda sad to see the older green signs dissapearing, to the new style.

[Quillz]

I find exit numbers useful if I know how long a highway is within the state. For example, I-5 is just under 800 miles, so when I'm at "Exit 790," I know I'm almost at the Oregon border and likely some roadside services.

[J N Winkler]

And if our exit tabs were similarly a different color, I wouldn't have a problem. Green on green just doesn't contrast. Mr. Asphalt Planet, to accuse me of being subjective implies that your opinion is objective, which it isn't. At least I'm informed by being a traffic engineer in addition to an enthusiast.

I asked you to cite your position to verify its validity.  Given that you didn't it's probably fair to infer you can't.

And I said I'm an engineer, so I'm using engineering judgment and experience. That's a perfectly valid position to hold.

But this is not a venue where simple invocation of engineering judgment wins arguments.  Strictly speaking, engineering judgment has meaning only in contexts regulated by engineering practice legislation.

For what it is worth, I think there is something in the conspicuity argument for exit tabs, but I know of no study which has investigated tab placement and formatting specifically.  Perhaps this is something that could be done through the TCD pooled-fund study.

[Alps]

And if our exit tabs were similarly a different color, I wouldn't have a problem. Green on green just doesn't contrast. Mr. Asphalt Planet, to accuse me of being subjective implies that your opinion is objective, which it isn't. At least I'm informed by being a traffic engineer in addition to an enthusiast.

I asked you to cite your position to verify its validity.  Given that you didn't it's probably fair to infer you can't.

And I said I'm an engineer, so I'm using engineering judgment and experience. That's a perfectly valid position to hold.

But this is not a venue where simple invocation of engineering judgment wins arguments.  Strictly speaking, engineering judgment has meaning only in contexts regulated by engineering practice legislation.

For what it is worth, I think there is something in the conspicuity argument for exit tabs, but I know of no study which has investigated tab placement and formatting specifically.  Perhaps this is something that could be done through the TCD pooled-fund study.

I know of no such study offhand, but the FHWA has considerable archives. I trust that the MUTCD has put considerable thought into its rulemaking.

[J N Winkler]

I know of no such study offhand, but the FHWA has considerable archives. I trust that the MUTCD has put considerable thought into its rulemaking.

Having had some experience with the MUTCD rulemaking process, it is evident to me that the research support for individual provisions of the MUTCD is uneven.  For example, the stippled-arrow diagrammatics (part of the MUTCD since the 1970's) were the result of a major study incorporating both tachistoscope work and real-world test signs (including the famous 70S/Democracy Blvd. sign).  In comparison, the recent addition of arrow-per-lane diagrammatics was based entirely on tachistoscope work.  The MUTCD also now has a fair number of warning signs whose research origin appears to be a synthesis of existing practice among state DOTs, which did not and was not intended to investigate the effectiveness of those signs (this is the same study that was eventually discovered by MTR denizens and found to have many unattributed road enthusiast photos).

The FHWA MUTCD team has very good access to research work, including work done by state DOTs and universities which has not yet entered a formal publications process.  However, I am skeptical that there is a major study into exit tab design which is hidden from TRIS and similar search engines.

It is certainly true that the MUTCD does specify that exit numbers should be put on a "separate plaque at the top of the Advance Guide or Exit Direction sign," but this language has not changed between the 2003 and 2009 editions of the MUTCD (in 2003 it appears at § 2E.28; in 2009 it appears at § 2E.31).  While the illustrations have invariably shown part-width tabs which are not part of the main sign panel, I see little evidence that this particular provision has ever been interpreted (either by FHWA or a state DOT) to prohibit full-width tabs which are structurally part of the main sign panel, as used in Illinois DOT District 1 and in Washington state.  It could even be argued (rather jesuitically) that the California bitten-out tabs comply since they are bordered overlays on one part of the sign panel (thus visually separate from the main panel legend) and their top edges coincide with the top edge of the sign.

In my view, the real problem with Caltrans exit tabs has less to do with their format and more to do with the fact that they are substandard in terms of letter and digit height (and can force legend on the main sign panel to substandard heights if designed to accord with Caltrans TOPS circular 02-04).  But this is something for which Caltrans civil engineers have collectively accepted responsibility through the exercise of engineering judgment.  You may not agree with it, I may not agree with it, and even California FHWA staffers may find it hard to swallow, but in view of the fact that implementing a pure vanilla approach to tab placement and format in California would entail significant added hardware costs, I can see why they settled for half a loaf.

[myosh_tino]

In my view, the real problem with Caltrans exit tabs has less to do with their format and more to do with the fact that they are substandard in terms of letter and digit height (and can force legend on the main sign panel to substandard heights if designed to accord with Caltrans TOPS circular 02-04).

I'm sure the 120-inch maximum sign panel height also played a role in determining the size of the exit "tabs" (24" tabs, 8" EXIT, 12" numerals) and the if needed reduction of the main legend from 16/12 to 13.3/10 (or smaller).

There's also a note in the California Coded Sign Specifications page that new sign specs (or changes to existing sign specs) relating to changes made in the 2012 California MUTCD are due shortly. It will be interesting to see what's added or deleted and what gets changed.