[USA] United States Interstate Highways

[FM 2258]

Originally Posted by musiccity

I-40 in Nashville
<snip>

I-40/I-24 Interchange

Nice pictures. Great arrows, I say if it ain't broke don't fix it. I think I said it before...in my mind if the arrow points down it means you're staying on the highway, if it points up, you're leaving the highway for another roadway.

[-Pino-]

Originally Posted by myosh_tino

The #3 lane (counting from the left) IS an option lane for I-70 or I-435 North. In that case, isn't an arrow-per-lane sign required per the 2009 MUTCD Sec 2E.20?

The photo suggests that the #3 is NOT an option lane, but a through lane. After the I-435 South exit, a separate exit lane appears on the right to carry traffic to the I-435 North.

To revert on JN Winkler's thoughts, I can see his reasoning, but his proposed signs (pretty much the pre-2009 system) is, in my opinion, equally likely to provoke uncessary lane changes. Topeka and Wichita-bound traffic might leave the #3 lane because it seems to head to Des Moines. Of course, the fact that there is no EXIT ONLY above that lane tells you that you will not be forced to turn off to Des Moines, but the arrow suggests something different. In other words: the message of the old system is counter-intuitive. Presumably that is why the MUTCD with the standing arrows / European system came into being in the first place.

It may be because I am European, but I absolutely believe that the new system is the better approach. I do appreciate that the standing arrows are not ideal when it comes to signposting two exits in quick succession, but as I mentioned, neither was the old system. One could play around a bit by not placing Topeka and Wichita next to each other on the sign, but to rather place them underneath each other. That would keep Topeka-bound traffic on lane #3, but you then still need to introduce a form of advance warning to traffic exiting to Wichita. You pretty much want them in lane #3 at this stage ...

[Traffic Eng.]

I would have to agree to -Pino-'s post, but that's just because I'm European too . Without reading the previous posts I imagined that it would be easier to confuse the locals (at least in the first time) with the changes than confusing a first-timer.

So I'd say the arrows over lane signage is pretty good. Wichita is in the middle of one lane when Topeka is in the middle of two lanes, from here it's pretty intuitive that only one arrow is for Whichita and two arrows are for Topeka.

The signs are already installed and I think it's worthy to observe how well they actually work.

[myosh_tino]

Originally Posted by -Pino-

The photo suggests that the #3 is NOT an option lane, but a through lane. After the I-435 South exit, a separate exit lane appears on the right to carry traffic to the I-435 North.

I think you have your directions mixed up. The first exit on I-70 West is to I-435 North, the second exit is to I-435 South. Also, the #3 lane IS an option lane as you have the option to stay on I-70 West or exit onto I-435 North. You are correct that just past the exit a new exit-only lane to I-435 South forms.

Originally Posted by -Pino-

To revert on JN Winkler's thoughts, I can see his reasoning, but his proposed signs (pretty much the pre-2009 system) is, in my opinion, equally likely to provoke uncessary lane changes. Topeka and Wichita-bound traffic might leave the #3 lane because it seems to head to Des Moines. Of course, the fact that there is no EXIT ONLY above that lane tells you that you will not be forced to turn off to Des Moines, but the arrow suggests something different. In other words: the message of the old system is counter-intuitive. Presumably that is why the MUTCD with the standing arrows / European system came into being in the first place.

But I believe the way the new arrow-per-lane sign is laid out causes even more driver confusion because it implies that vehicles in the #2 lane may also exit to I-435 South when in reality, if you're in the #2 lane you would need to dive across 2 lanes to make the exit. At least with the pre-2009 MUTCD style, the advance guide sign for I-435 South gives an indication that those wanting to take that exit should move into the rightmost through lane.

Originally Posted by -Pino-

It may be because I am European, but I absolutely believe that the new system is the better approach. I do appreciate that the standing arrows are not ideal when it comes to signposting two exits in quick succession, but as I mentioned, neither was the old system.

I believe the new arrow-per-lane signs can be useful but I think their use should be limited to where the next exit must be at least 1 mile ahead to allow proper advance guide signing. I am also not a fan of overly tall signs (I'm from California where the max overhead sign height is 10 ft.) and the amount of wasted space the new arrow-per-lane signs tend to have.

[-Pino-]

Originally Posted by myosh_tino

But I believe the way the new arrow-per-lane sign is laid out causes even more driver confusion because it implies that vehicles in the #2 lane may also exit to I-435 South when in reality, if you're in the #2 lane you would need to dive across 2 lanes to make the exit. At least with the pre-2009 MUTCD style, the advance guide sign for I-435 South gives an indication that those wanting to take that exit should move into the rightmost through lane.

You might even be able to do so out of the #1 lane. You've got about a quarter of a mile to go before the exit and, provided that traffic levels are low enough, you can easily cross a few lanes and make the exit. What is important, however, is an indication how far away the I-435 South exit is. On comparable signs in Europe that will find that distance. The combination of traffic density and distance indication allows the motorist en route to the I-435 South to decide when to move to lane #3.

I believe the new arrow-per-lane signs can be useful but I think their use should be limited to where the next exit must be at least 1 mile ahead to allow proper advance guide signing. I am also not a fan of overly tall signs (I'm from California where the max overhead sign height is 10 ft.) and the amount of wasted space the new arrow-per-lane signs tend to have.

The wasted space tends to come with better overview when compared to three separate overhead signs. Which is also worth something. But I do agree that sign makers should be careful not to overdimension their gantries.

I would not say that all cause for the arrow-per-lane signs is lost if the next exit is closer than 1 mile. But you need to be careful in announcing the next exit through your lane allocation. In my opinion, you need a much more neutral approach that simply says how far away the next exit is and then only start allocating lanes for that next exit after you have passed the initial exit. But to be honest, I think the same of working with the old falling arrows.

[myosh_tino]

Originally Posted by -Pino-

You might even be able to do so out of the #1 lane. You've got about a quarter of a mile to go before the exit and, provided that traffic levels are low enough, you can easily cross a few lanes and make the exit. What is important, however, is an indication how far away the I-435 South exit is. On comparable signs in Europe that will find that distance. The combination of traffic density and distance indication allows the motorist en route to the I-435 South to decide when to move to lane #3.

I'm sorry but diving across 3 lanes in a quarter mile, even in light traffic, is dangerous even borderline reckless and will earn you a ticket if a cop sees you do it. While the arrow-per-lane sign does not provide a distance to the I-435 South exit, the drawing I posted upthread does provide a distance for the I-435 South advance guide sign (1/4 mile).

[J N Winkler]

Originally Posted by myosh_tino

Wait a minute. The I-70/I-435 North exit, where the arrow-per-lane sign is installed does have an option lane that carries the through route. The #3 lane (counting from the left) IS an option lane for I-70 or I-435 North. In that case, isn't an arrow-per-lane sign required per the 2009 MUTCD Sec 2E.20?

I would contend not. My interpretation of the 2E.20 criterion is that the exit carries the through route--i.e., the interchange is a TOTSO. In this case there is an option lane for I-70 and I-435 but I-70 itself does not follow the exit.

The actual wording in 2E.20 is as follows:

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).

It comes down to what is meant by "optional exit lane." If the intention is to require diagrammatics at all major interchanges which have an option lane, then it is not necessary to specify that the "optional exit lane" also carries the through route or, for that matter, to specify that it is an optional exit lane.

I think the intention is actually to limit the requirement to TOTSO situations and splits, a fairly narrow application which is a traditional concern in the literature on driver expectancy. The MUTCD allows arrow-per-lane diagrammatics to be used in other situations where an option lane is present but it does not actually mandate them.

By the way, thank you for drawing my suggested approach. It is actually correct for MUTCD 2003. A couple of changes are necessary to update it for MUTCD 2009. First, in the first gantry the second arrow needs to be dropped from the advance guide sign for Exit 8A, so that it is a simple lane-drop sign with just one down arrow against a yellow panel. Second, in the second gantry, the bottom yellow panel has to extend across the full width of the lane-drop exit direction sign for Exit 8A (so that both "exit" arrows are black against yellow).

Pino is correct to say that the old (2003) arrangement encouraged drivers to make unnecessary lane changes to avoid the option lane. That is the rationale for the current (2009) approach, which is based (if memory serves) on a simulator study which Jonathan Upchurch carried out at the University of Massachusetts in 2003. It does encourage drivers to make unnecessary lane changes into the dropped lane when they can equally well take the option lane for the exit, but the consequences of this tend to be more benign because the driver is moving right (rather than left) and is expecting to exit. The MUTCD recommends ground-mounted lane assignment signs (regulatory colors) to warn drivers of the option lane condition at such exits, and some state DOTs have tried part-width arrow-per-lane diagrammatics which show just the dropped lane and the option lane (not the through lanes).

[ScraperDude]

The interchange you guys are discussing is a dream come true compared to the rest in Kansas City. This entire city is PLAGUED with left exits, left lanes that end (I-435 Eastern leg Missouri side) as soon as a major ramp joins I-435 from the right, that lane continues and the left lane ends and what was a middle lane becomes the new left lane which in turn causes semi-trucks to now be traveling in the left lane.... for miles.... this madness starts at I-435 and I-35 NE Kansas City metro, I-435 and Parvin rd, I-435 and Armour rd (just one mile south of Parvin rd) and finally at the I-435 and I-70 interchange you are discussing.

People are always shooting across 4 or 5 lanes of traffic to reach a left exit here.

[Tommy Boy]

Does it have a site of the project in Kansas City, or pictures. Thanks

[myosh_tino]

Originally Posted by J N Winkler

I would contend not. My interpretation of the 2E.20 criterion is that the exit carries the through route--i.e., the interchange is a TOTSO. In this case there is an option lane for I-70 and I-435 but I-70 itself does not follow the exit.

The actual wording in 2E.20 is as follows: ...

Hmm... that's not how I interpreted 2E.20. If I may, here is Figure 2E-4 from the 2009 MUTCD which is referenced in your quote from Sec 2E.20...


In this example, I-84 is the through route and the exit is for route 72. This does not look like a TOTSO situation to me. It looks like a standard multi-lane exit with an option lane.

[J N Winkler]

Myosh_tino: yes, you are right, that is not a TOTSO. My interpretation is that it shows the permissive case: an arrow-per-lane diagrammatic may be used but is not required to be used. Note that the drawing caption does not state that the interchange is "major," which is part of the "must" condition in the Standard statement in 2E.20.

[Tom 958]

Originally Posted by J N Winkler

Myosh_tino: yes, you are right, that is not a TOTSO. My interpretation is that it shows the permissive case: an arrow-per-lane diagrammatic may be used but is not required to be used. Note that the drawing caption does not state that the interchange is "major," which is part of the "must" condition in the Standard statement in 2E.20.

Indeed. There are many, many such splits in (for instance) Atlanta, the vast majority of which are just lane drop ramps for service interchanges. If using arrows-per-lane signage was mandatory, it would blur the distinction between a major fork and just another offramp.

As a matter of fact, I remember that sometime in the early '80's GaDOT put old skool diagrammatic arrows at a few such ramps (I-20 and Wesley Chapel Road was one), but took them down after a few months, possibly out of common sense or possibly because FHWA informed them that their interpretation of the then-current MUTCD was incorrect.

Speaking of which, a few months ago I posted about the signage for Atlanta's I-85 HOT lanes having to be redone before the lanes opened because they were at odds with the MUTCD. They looked stupid, too.

EDIT: That said, Connecticut 72 is a freeway, so IMO the signage myosh_tino posted would be appropriate there.

[AUchamps]

I don't like the "California look" for Exit Only. Give me the more conventional style. It's bad enough that we're losing Highway Gothic to Clearview but now this? Give me a freakin' break.

[ChrisZwolle]

What is actually so bad about Clearview? I don't understand all the fuss about it among road enthusiasts. It looks like a fine font to me, it's better than most fonts used in Europe for instance.

[myosh_tino]

Originally Posted by ChrisZwolle

What is actually so bad about Clearview? I don't understand all the fuss about it among road enthusiasts. It looks like a fine font to me, it's better than most fonts used in Europe for instance.

While I suppose I could live with the letters, Clearview numerals are absolutely hideous. Series E/E(M) and D numerals are far superior IMO.

[Rail Claimore]

I'm fine with Clearview, and it works well for white letters on dark backgrounds. But for black letters on light backgrounds, it's atrocious.

[desertpunk]

Green power coming to a freeway near you?



Concept is from 2007 but kinda interesting nonetheless.

[Paddington]

Hideous

[diablo234]

Originally Posted by desertpunk

Green power coming to a freeway near you?



Concept is from 2007 but kinda interesting nonetheless.

I don't see that generating much wind power.

[g.spinoza]

Better than nothing...