"Multiplex?"

[hbelkins]

Does anyone know the origin of the term "multiplex" to describe two or more numbered highways running concurrently?

Myself, I hate that term. I prefer "concurrent" or some variation of that word, "co-signed," "routed together," "share pavement" or any number of other words or phrases.

Right: I-64 and I-75 run concurrently around the north and east sides of Lexington.
Right: US 60 and US 460 used to share pavement between Frankfort and Louisville before the latter was decommissioned.
Right: I-64 and I-77 are co-signed along the West Virginia Turnpike between Beckley and Charleston.

Wrong: US 23, US 119, US 460 and KY 80 are multiplexed through Pikeville and south to the Shelbiana area of Pike County.

[xonhulu]

Does anyone know the origin of the term "multiplex" to describe two or more numbered highways running concurrently?

Myself, I hate that term. I prefer "concurrent" or some variation of that word, "co-signed," "routed together," "share pavement" or any number of other words or phrases.

Right: I-64 and I-75 run concurrently around the north and east sides of Lexington.
Right: US 60 and US 460 used to share pavement between Frankfort and Louisville before the latter was decommissioned.
Right: I-64 and I-77 are co-signed along the West Virginia Turnpike between Beckley and Charleston.

Wrong: US 23, US 119, US 460 and KY 80 are multiplexed through Pikeville and south to the Shelbiana area of Pike County.

I agree with you on disliking "multiplex" or any of its variants, like "duplex" or "triplex."

My preference would be "co-signed," with or without the hyphen.

[NE2]

m.t.r.

"Overlap" sounds most natural to me. "Co-signed" doesn't work if the routes aren't signed.

[hbelkins]

m.t.r.

I knew that, but I can't remember who coined the term.

[triplemultiplex]

My opinion of it's use should be obvious.


Might have something to do with growing up in an area where the movie theater only has one screen.  The more common definition is just not something in the lexicon of my past.  (You can go to the same building with people and see different movies?!)

I can always say it's a more technical word for "menage a trois". 

[english si]

merger is (was) the official UK term - as shown in documents from before WW2. I've been using it on SABRE (and concurrent) for ages, but the rest SABRE keeps on using multiplex almost universally. 

[Mapmikey]

In older CTB documents Virginia has used the terms "overlay" and "concurrency"


Mapmikey

[J N Winkler]

Multiplex is fundamentally an electrical engineering term and I remember it from my first days on MTR back in 2001.  As applied to route overlaps, it has always grated on me.  It implies a focus on routing at an abstract, topological level that not only fails to do justice to the historical, cultural, and scenic attributes of the road under discussion, but also is frequently not supported by the actual administrative detail of route designation.

This said, the electrical engineering definition of multiplex actually makes more sense than the movie-theater definition when applied to route overlaps.  The former usage is also older (Wikipedia suggests 1910 versus 1930's).

[ChoralScholar]

I like multiplex because you can add other descriptors, like 'wrong-way multiplex' or 'unsigned multiplex'.  I'm not sure how you would describe those situations with the word 'concurrent' or some such.

[xonhulu]

I like multiplex because you can add other descriptors, like 'wrong-way multiplex' or 'unsigned multiplex'.  I'm not sure how you would describe those situations with the word 'concurrent' or some such.

"Wrong way concurrency" or "unsigned concurrency?"  Sounds o.k. to me.

For that matter, "wrong-way overlap/unsigned overlap" works, too.  Ditto with "overlay."

Unfortunately, my preferred term, "co-sign," doesn't lend itself to this:  "wrong-way co-signage" sounds awkward, and "unsigned co-signage" sounds moronic.

[Avalanchez71]

How about the concurrent multi-plex?  There is a famous one in Nashville where US 70 and US 70S are concurrently multi-plexed.

[Duke87]

As a kid the term I always used was "merge", e.g "route 73 and route 86 are merged for this section of road".

Since I actually started talking to other roadgeeks I've dropped this in favor of "multiplex" or "concurrency" since those are the terms people here commonly understand (to be fair "merge" with respect to roads can also mean something else unrelated, so it isn't a great term for this use).

"Multiplex" has the advantage of being one syllable less, so it makes extended terms like "wrong way multiplex" that much less of a mouthful. But in other situations I have no preference. 

[Scott5114]

I tend to use "concurrency" and "overlap", switching it up to whichever seems more appropriate. So I might say "the US-77/SH-39 concurrency" but "US-77 and SH-39 overlap through Purcell".

Multiplex seems to have fallen out of favor recently. One neat thing about "multiplex" is that you can specify the number of routes if you elect: duplex, triplex, quadruplex... etc.

[bugo]

I hate it too.  I am guilty of saying "duplex" but i prefer "overlap" or a simple "route x/route xx".  Being from Arkansas, I like the term "piggyback".

[realjd]

Multiplex is an old engineering term and has nothing to do with movie theaters. It's used to describe multiple signals being combined to travel across the same medium. Applying it to roads makes sense IMO.

http://en.wikipedia.org/wiki/Multiplexing

[Pete from Boston]

Oldest reference I can find on Google is by one Bob Goudreau, 3/21/1997:

https://groups.google.com/d/msg/misc.transport.road/Uv0QHLoi1oI/B4ayAVLFTnQJ

"But if a northbound interstate (increasing numbers) happened to be
multiplexed onto a *westbound* interstate (decreasing numbers)..."[/list]

[NE2]

I don't think the Goog's archive goes back before 1997.

[Alps]

Oldest reference I can find on Google is by one Bob Goudreau, 3/21/1997:

https://groups.google.com/d/msg/misc.transport.road/Uv0QHLoi1oI/B4ayAVLFTnQJ

"But if a northbound interstate (increasing numbers) happened to be
multiplexed onto a *westbound* interstate (decreasing numbers)..."[/list]

"Multiplexed onto" vs. "multiplexed with", the latter of which is the current usage. The former is more in the engineering sense.

[Pete from Boston]

I don't think the Goog's archive goes back before 1997.

I wish it didn't.  I'd be spared facing the stupid things I said in college otherwise, but sasly they're there.

[NE2]

Aha: http://groups.google.com/advanced_search
Looks like m.t.r was created in December 1995.

HB uses multiplex in response to a post by harry "bugo" sachz: https://groups.google.com/d/msg/misc.transport.road/iI9Ibxs-NPY/TIQmdy2qoLIJ

This seems to be the first use (July 15, 1996), also by Bob Goudreau:
https://groups.google.com/forum/#!topic/misc.transport.road/-BK863Z5o-s

Well, sure, there are lots of places where two routes are multiplexed
onto a single dual-signed roadway.  Where the routes diverged, one
route often has to be accessed by an exit off the other.  Local
examples for me include I-40/I-85 between Greensboro and Hillsboro:
since the I-85 mileposts and exit numbers are used on this dual-signed
stretch, you have to take a numbered exit to remain on I-40 in either
direction.  Even closer to me is the I-440 Raleigh Beltline; the bottom
half of this road is also I-40, so you have to exit in order to stay
on 440.

----------------------------------------------------------------------
Bob Goudreau                        Data General Corporation
goud...@dg-rtp.dg.com                62 Alexander Drive       
+1 919 248 6231                        Research Triangle Park, NC  27709, USA

Sig included because it provides definite evidence of an adaptation of the network definition.

[froggie]

There's worse MTR adages than the term "multiplex".  "BGS", for one...

[Henry]

You know, I used to say multiplex quite a lot, especially back when I first became an Internet regular, but I see that there are some better terms out there; concurrency and overlap are my top two. However, I hate the term duplex; it makes me think of a large house that's literally divided into two smaller ones.

[Pete from Boston]

There's worse MTR adages than the term "multiplex".  "BGS", for one...

Is "button copy" an MTRism?

[agentsteel53]

Is "button copy" an MTRism?

nope.  I have Caltrans references as old as 1978 which refer to "reflector button copy" and "button copy".  I probably have older; just don't have my files organized as well as I would like.

[NE2]

There's worse MTR adages than the term "multiplex".  "BGS", for one...

On the other hand, 'big green sign' works well when talking to a non-roadgeek.