Author Topic: AR I-55(7) broken multiplex  (Read 185 times)

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Offline yakra

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AR I-55(7) broken multiplex
« on: January 31, 2019, 12:52:34 am »
Looking at I-55(7)/AR77.
I-55's concurrency with I-40,US61,US64,US79 is broken.

This interchange complex and its associated multiplexes were a bit of a PitA to iron out in Operation Arkansas Cleanup.
At that time, I chose to call it part of the Exit 277 interchange, in order to maintain the concurrencies, and because I-40 & US79 have no access there.

How to handle it? Yecch...
I'm thinking maybe remove the point from I-55, and leave it in place on AR77? There are similar situations in TX where a route intersects another's frontage road(s), with no direct access to the route itself. (Meh, it's imperfect, but so are double trumpets.)

Offline froggie

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Re: AR I-55(7) broken multiplex
« Reply #1 on: January 31, 2019, 09:32:23 am »
A few possible solutions:

- If you keep the point, you'll need to add it to US 61 and US 64 since both routes are concurrent with I-55.
- You could remove the point entirely for the freeway and just leave it on AR 77 as you suggest.  I would concur with this solution.
- Add it to US 61/US 64 as noted above and make it a hidden point on I-40/US 79.  Sure, you may incur a case where someone coming south on I-55 and exiting there would then log a concurrency with I-40/US 79 when they were never on I-40, but at last check the number of users actually using the waypoint for Exit 7 is a nice round number (literally).

Offline mapcat

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Re: AR I-55(7) broken multiplex
« Reply #2 on: January 31, 2019, 02:05:27 pm »
I'll add the point to US 61 & US 64. Not sure what would be served by adding it as a hidden point on the others, except for preserving a concurrency that isn't really a concurrency there.
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Offline mapcat

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Offline Duke87

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AR: I-40/I-55 (and US61/64/79) concurrency broken
« Reply #4 on: April 15, 2019, 07:51:22 pm »
I-40 point "277" and I-55 point "8" are at the same coordinates and should mark the beginning of the concurrency between these two routes. But the concurrency doesn't detect until I-40 point "278" / I-55 point "278(40)", because of the existence of an intervening point "7" on I-55 that does not exist on I-40.

That "7" point corresponds to a single ramp that is accessible only from I-55 southbound. So it is correctly not a point for I-40 except that this breaks the concurrency.

Seems to me one of two things should be done to fix this:
Option 1) Add "+7(55)" to I-40 as a hidden point, with the same coords as the point on I-55. This would generate a visible/hidden collocation error that would need to be marked as FP, and a "+7(I-55)" point would also need to be added to US 79.
Option 2) Just get red of the "7" point on I-55 (it is not currently in use) on the grounds that it's more or less within the footprint of the I-55/I-40 junction, and thus the one point per interchange policy can be invoked. This would also require eliminating "I-55(7)" from US 61 and US 64.
« Last Edit: April 15, 2019, 07:57:02 pm by Duke87 »

Offline rickmastfan67

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Re: AR: I-40/I-55 (and US61/64/79) concurrency broken
« Reply #5 on: April 15, 2019, 11:09:26 pm »
Oof, this is an annoying one.

I'm going to have to side IMO with Option 1.

Option 1) Add "+7(55)" to I-40 as a hidden point, with the same coords as the point on I-55. This would generate a visible/hidden collocation error that would need to be marked as FP, and a "+7(I-55)" point would also need to be added to US 79.

Reason?  You have AR-77 in the mix there, and thus, can't invoke the "one point per interchange policy".  If it wasn't there, I could side more with option 2.

Only difference with US-79 is that I would label the hidden point as "+I-55(7)" to keep it naming wise in sync with the rest of the multiplex.
« Last Edit: April 15, 2019, 11:12:42 pm by rickmastfan67 »

Offline yakra

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Re: AR I-55(7) broken multiplex
« Reply #6 on: April 15, 2019, 11:46:27 pm »
Topics merged.

Option 2) Just get red of the "7" point on I-55 (it is not currently in use) on the grounds that it's more or less within the footprint of the I-55/I-40 junction, and thus the one point per interchange policy can be invoked. This would also require eliminating "I-55(7)" from US 61 and US 64.
This gets my vote. It's what I did for Operation AR Cleanup (see upthread).

- You could remove the point entirely for the freeway and just leave it on AR 77 as you suggest.  I would concur with this solution.
:D
« Last Edit: April 15, 2019, 11:59:58 pm by yakra »