multilane exit signage on freeways

[myosh_tino]

Here is one other option that's been used in California although it's not as common.  Instead of the down arrows for the I-5 pull through, replace them with the text "LEFT 4 LANES".  For the CA-57 advance sign, replace the arrows with "3/4 MILE" and rely on signs further up the road to provide lane guidance...

[agentsteel53]

that might very well be doable, with the possible problem that counting to four while driving down the freeway may be a bit tricky.  "am I in the fourth or fifth lane?  do I need to change lanes?"

I think for three lanes or fewer that is a very viable solution, but at four it starts getting a bit computationally unwieldy.  This is one difficult intersection to sign clearly!

[myosh_tino]

In regards to Myosh_tino's comments on Caltrans getting a waiver for arrow-per-lane diagrammatics, I don't think they will.  I don't think they can obtain a waiver from a Standard statement, and they are already using arrow-per-lane diagrammatics.  What I think will happen is that they will find some way of not complying with the arrow height requirements.  I think the MUTCD's arrow height requirements are a bit excessive--for example, they require 72" arrows in some contexts, which is double the shield height.  The arrows are also required to be centered over the lanes to which they apply, and I think this requirement is unnecessary for arrow-per-lane diagrammatics.  I support this requirement for downward-pointing arrows on other signs, but not for upward-pointing arrows on diagrammatics, because I think the two are interpreted differently by motorists.

I was perusing the current California MUTCD which is the 2003 MUTCD plus the California supplement and I did notice there were numerous crossed out sections marked "Standard:" in bold type and below it, was the California "replacement" for the crossed out section in blue.  The sections that were crossed out included those related to HOV lane signage (sec 2B.26 and 2B.27), hazardous material signs (2B.52) and advisory exit speed signs (2C.36).  It also looks like Caltrans had a habit of changing "shall" to "should" with in the "Standard" section and then including their own "Guidance" section.

Also, it looks like Caltrans has started the process of building their Supplement to the 2009 MUTCD.  A note posted on their website says they have until 2012 to submit their supplement though they expect to have it done sooner.  Until the new supplement is finished and approved, the 2009 MUTCD will not be in effect and California will continue to use the 2003 MUTCD + supplement.

[TheStranger]

Here is one other option that's been used in California although it's not as common.  Instead of the down arrows for the I-5 pull through, replace them with the text "LEFT 4 LANES".  For the CA-57 advance sign, replace the arrows with "3/4 MILE" and rely on signs further up the road to provide lane guidance...

This setup actually resembles one of the signs on westbound I-80/eastbound I-580 approaching the Macarthur Maze.  However, in the Oakland example I mention, it's the Right 3 Lanes that continue on for I-80 (while the rest feed into either 580 east or 880 south).

[J N Winkler]

This is my attempt at a signing scheme which complies with the 2009 MUTCD:















Some observations:

*  The optional lanes are "hidden" until the last minute.  I personally do not consider this desirable, but it is what falls out of the requirement in § 2E.19 not to use downward-pointing arrows except over lanes which go exclusively to the destinations above the arrow.

*  In each case, the "double exit" sign is placed downstream of the theoretical gore point (i.e., after the optional lane has already divided into two).

*  For the closely spaced SR 22 and SR 57 exits, the "EXIT ONLY" condition for the following exit is not signed until the same gantry as the exit direction sign for the current exit.  This is because "EXIT ONLY" is misleading when placed over an optional lane which will not become a lane drop until after the current exit is passed.  This is not something that has changed between the 2003 and 2009 editions of the MUTCD.

I think Scott's scheme complies substantially with the 2003 edition, but not the 2009 edition.  My only quibble is the use of one, rather than zero or two, downward-pointing arrows on the advance guide signs for SR 57/Pomona.  If you are going to use a signing method which allows multiple downward-pointing arrows over a single lane (now banned in the 2009 edition) or over optional lanes, it has to be done on a consistent and easily understood basis, such as providing an arrow over every lane which can be used to reach the destination referred to by the arrow.  The signing scheme as currently drawn does not show what happens if you take the "straight ahead" option for SR 22 until after you have passed the SR 22 exit, at which point it magically becomes the lane drop for the SR 57 exit.  It could easily confuse a driver into making an unnecessary lane change to the left (i.e., the optional lane for the SR 57 exit) rather than staying in the optional lane that eventually becomes the SR 57 lane drop.  The driver would feel he or she had to move into the lane which a gantry upstream of the SR 22 exit clearly indicated went to SR 57.

I personally think the best solution compliant with the 2003 edition (not that it is very good; in fact I think the close concatenation of exits for SR 57 and SR 22 is an apt illustration of the old engineer's adage, "If you can't sign it, don't build it") is what Caltrans has actually installed.

[Scott5114]

in fact I think the close concatenation of exits for SR 57 and SR 22 is an apt illustration of the old engineer's adage, "If you can't sign it, don't build it"

Heh, that's along the lines of what I thought when I was doing all this, except I had no idea that was an actual engineer's phrase!

[J N Winkler]

In fact I think the close concatenation of exits for SR 57 and SR 22 is an apt illustration of the old engineer's adage, "If you can't sign it, don't build it"

Heh, that's along the lines of what I thought when I was doing all this, except I had no idea that was an actual engineer's phrase!

In fact, it is a paraphrase from a Caltrans internal publication on preparing signing plans which was co-produced by HQ Traffic and District 7 (Los Angeles) in the late 1980's/early 1990's.  According to this book, one of the steps of the project development process is for the sponsoring District to contact HQ Traffic at an early stage to identify any design changes that may be necessary for the project to be signed correctly.

In practice, however, I think the roadway designers steal the traffic engineers' lunch money.

[aswnl]

I like it most the German way, with arrows pointing up.
(which has also been introduced in my homecountry last year)

German example:


Dutch example:

[froggie]

I like it most the German way, with arrows pointing up.
(which has also been introduced in my homecountry last year)

Was also recently introduced here in the 2009 MUTCD.  I've seen them on I-29 in Fargo, ND (only place I can think of offhand...)

[Truvelo]

The German arrow design also solves the problem of having more arrows than lanes as discussed earlier in this thread with the I-5 gantry.

[TheStranger]

The brand new signage eastbound at the US 50/Business 80/Route 99 split in Sacramento utilizes those German forked arrows as well...

[SSOWorld]

as does one sign in Milwaukee at the McKinley Blvd exit.

[joseph1723]

Ontario also uses the forked arrow design for their multilane exits since the mid 90s when bilingual signs where introduced.

Here's a typical Ontario advance exit sign:


There is also a ground mounted yellow lane assignment sign that also has the same arrows on them at each exit.

Before the current design our multilane exit signs used to look like this drawing:

[UptownRoadGeek]

Houston has their own version as well.

U.S. 59 NB approaching Louisiana St

I-10 WB @ U.S. 59

[TheStranger]

Something I saw today on the way home - a nice older example (ca. 1982?) of a forked arrow out here in Sacramento, where Business 80 takes the ramp to continue west onto westbound US 50 (and northbound Route 99): http://bit.ly/7wqmed

Northbound Route 99 also has a similar sign, as it uses a ramp to enter the concurrency with US 50 and Business 80: http://bit.ly/92P95y

[agentsteel53]

wait, what's the difference between this newfangled German "forked arrow" and a good old fashioned American diagrammatical??  Apparently one has been around for years, and the other is a product of the 2009 MUTCD...

[TheStranger]

wait, what's the difference between this newfangled German "forked arrow" and a good old fashioned American diagrammatical??  Apparently one has been around for years, and the other is a product of the 2009 MUTCD...

Isn't the typical diagrammatical arrow (as far as I understand it) the ones with the lane dashes within them?  Or is that a more specific variant of the whole type?

[joseph1723]

Ontario also posts similar diagrammatic signs along with the forked arrows at large and or unusual interchanges. The usual sequence for a diagrammatic is like this example at Highway 403 and 407:

The diagrammatic goes first:


Then the forked arrows sign: (this one is a bit odd, since it's a 407 sign, regular ones are green)


And finally the sign at the gore with down arrows and pull through signage: The exit signage may have a yellow bar at the bottom similar to a "Exit Only" bar.

[agentsteel53]

good grief!  does Express Toll Route really deserve a Compress 407 Shield?

There's a reason Series D (as seen in the photo you emailed me) was invented: so that Series EM doesn't have to be scaled horizontally to 85% width.

[roadfro]

Isn't the typical diagrammatical arrow (as far as I understand it) the ones with the lane dashes within them?  Or is that a more specific variant of the whole type?

The diagrammatic arrow signs, which were a staple of previous versions of the MUTCD and retained as an option in the new manual, are the large arrows with 'stipples' or lane line dashes along the shaft of the arrow.

wait, what's the difference between this newfangled German "forked arrow" and a good old fashioned American diagrammatical??  Apparently one has been around for years, and the other is a product of the 2009 MUTCD...

The "forked arrow" is now the preferred method of signing multi-lane splits in the 2009 MUTCD.  The MUTCD refers to these as "arrow-per-lane" signs, with one upward pointing arrow positioned over each lane with 'forked' arrows where an option lane exists.

The MUTCD has not previously included the upward pointing arrows now found on "arrow per lane" signs, but some states (and obviously other countries) have used this method of signing splits and option lane exits for some time. The FHWA has decided to move in this direction for exit signing at certain splits instead of relying on down arrows and diagrammatics, as a study seems to indicate greater driver comprehension. Upward pointing arrows are preferred, as it is much easier to see individual arrows over each lane than counting the small dashed lines of a diagrammatic arrow. (See previous discussion relating to the study that examined multi-lane exit signing.)

[J N Winkler]

The German arrow design also solves the problem of having more arrows than lanes as discussed earlier in this thread with the I-5 gantry.

Actually it doesn't, as currently specified in the 2009 MUTCD--this is a point that emerged in discussion upthread.  The problem has to do with design of the arrows so that they indicate two exits, each of which has an optional lane, which occur in rapid succession.  Possible fixes include manipulating the bends in the arrow shafts (doesn't make the sign easy to read at high speed), or using taller arrows to allow portrayal of the double exit (increases sign panel area).

One solution I would suggest, which I have not drawn yet but may be able to get to before the end of this week (I thought this was going to be vacation but it hasn't been working out that way), is an adaptation of the Houston-style diagrammatic.

[Truvelo]

Someone posted this in another thread and it could work with multiple exits. In theory the arrow could be extended to show more than two exits.

[myosh_tino]

I was finally able to create reasonable copies of the new arrow-per-lane arrows that are specified in the new MUTCD.  These are not exact duplicates because I cannot find the specs for these new arrows.  Below are two versions of the I-15/I-40 one-half mile advance diagrammatic guide sign in Barstow, CA (one of the few diagrammatic signs in the state).  The first uses the 72-inch arrows (2 x the Interstate shield height) and the result is a very tall sign (almost 14 feet).  The second uses 54-inch arrows and it can fit in a standard 11 foot guide sign.  To minimize height, I elected to put the route shield next to the control city while the 2009 MUTCD has the route shield above the control city.

72-inch Arrows...


54-inch Arrows...


and for reference, the original sign...

[shoptb1]

I was finally able to create reasonable copies of the new arrow-per-lane arrows that are specified in the new MUTCD.  These are not exact duplicates because I cannot find the specs for these new arrows.  Below are two versions of the I-15/I-40 one-half mile advance diagrammatic guide sign in Barstow, CA (one of the few diagrammatic signs in the state).  The first uses the 72-inch arrows (2 x the Interstate shield height) and the result is a very tall sign (almost 14 feet).  The second uses 54-inch arrows and it can fit in a standard 11 foot guide sign.  To minimize height, I elected to put the route shield next to the control city while the 2009 MUTCD has the route shield above the control city.

It will be very interesting to see where this new suggested design is implemented first.  Just a guess, but I am willing to bet it won't be California.   

[Scott5114]

It will be very interesting to see where this new suggested design is implemented first.  Just a guess, but I am willing to bet it won't be California.   

You would be right. It was Milwaukee, actually.



The guys who designed this sign (in place during Summer 08!) just north of the Marquette Interchange must have been working off an advance copy of the 09 MUTCD...note that not only is it using the Canadian arrow treatment, but also the space between exit number and suffix that was added in the 09 MUTCD!