(https://i.imgur.com/1LBDvcr.jpg)
Is there an example of an interchange like this? I overlaid it on top of the University Parkway DDI in Florida for perspective. Below is a link to a similar interchange design i used for inspiration:
I-94 & Conner (Detroit, MI):
https://www.google.com/maps/@42.3957705,-82.9875861,388m/data=!3m1!1e3
Plenty of weaving and left-side merging to go around there, I see...
Quote from: kphoger on October 24, 2018, 02:10:02 PM
Plenty of weaving and left-side merging to go around there, I see...
The four green dots in the picture represent traffic signals. The traffic signals should help with the merge points.
Here is a simplified version of the interchange i was imagining:
(https://i.imgur.com/MrP59GN.jpg)
Huh. The interchange I thought of turns out to not quite match your drawing, but I stumbled upon a DDI in Mexico while I was looking. I didn't realize any DDIs existed there.
A mirror image with weaving instead of lights, MA 128 at US 20: https://www.google.com/maps/@42.3708793,-71.2696918,626m/data=!3m1!1e3
Somewhat close, I-270 at MO 100: https://www.google.com/maps/@38.6026606,-90.4503011,662m/data=!3m1!1e3
Quote from: NE2 on October 24, 2018, 03:27:29 PM
A mirror image with weaving instead of lights, MA 128 at US 20: https://www.google.com/maps/@42.3708793,-71.2696918,626m/data=!3m1!1e3
I was literally about to post a link to this interchange! It's not quite the same design though as the freeway off-ramps are outside of the "square".
Quote from: NE2 on October 24, 2018, 03:27:29 PM
A mirror image with weaving instead of lights, MA 128 at US 20: https://www.google.com/maps/@42.3708793,-71.2696918,626m/data=!3m1!1e3
I'm not entirely sure that's equivalent. I'm trying to trace where all the turning movements go in relation to one another, and it's making my brain hurt. At any rate,
here's the one I had thought of (https://goo.gl/maps/ynsXPJPhAyN2), but I don't think it's quite equivalent either.
Quote from: tradephoric on October 24, 2018, 03:35:30 PM
Quote from: NE2 on October 24, 2018, 03:27:29 PM
A mirror image with weaving instead of lights, MA 128 at US 20: https://www.google.com/maps/@42.3708793,-71.2696918,626m/data=!3m1!1e3
I was literally about to post a link to this interchange! It's not quite the same design though as the freeway off-ramps are outside of the "square".
You replied while I was typing. Yes, "outside of the square" describes what I was thinking didn't match up.
Quote from: tradephoric on October 24, 2018, 01:59:59 PM
(https://i.imgur.com/1LBDvcr.jpg)
↓ Here's my rendering of your interchange ↓
(https://i.imgur.com/G5CUISv.png)
Thank you kphoger! I'm not good with rendering these designs and botch them up pretty bad. Your drawing is much better at showing this conceptual design. If you get a chance could you render up the simplified interchange design too?
I feel like the grade might be too steep here.
Quote from: 1 on October 24, 2018, 04:16:25 PM
I feel like the grade might be too steep here.
Here's a streetview showing the interchange grade at I-94 and Conner in Detroit. After exiting the freeway, drivers only travel 620 feet before merging onto Conner Street. It gives you an idea of what the off-ramp grade might look like.
https://www.google.com/maps/@42.3957152,-82.9887019,3a,75y,29.5h,86.52t/data=!3m6!1e1!3m4!1s1tvG0JdEGYNLdo5zuJB2nw!2e0!7i16384!8i8192!5m1!1e1
Quote from: tradephoric on October 24, 2018, 04:16:02 PM
Thank you kphoger! I'm not good with rendering these designs and botch them up pretty bad. Your drawing is much better at showing this conceptual design. If you get a chance could you render up the simplified interchange design too?
Quote from: tradephoric on October 24, 2018, 02:52:06 PM
(https://i.imgur.com/MrP59GN.jpg)
(https://i.imgur.com/Wai7nZE.png)
Quote from: 1 on October 24, 2018, 04:16:25 PM
I feel like the grade might be too steep here.
Depends how much land the interchange takes up. Look at the Mexican almost-example I linked to earlier.
I created a model of the interchange in SYNCHO.
https://www.youtube.com/watch?v=2IZ3lzQ3ISA&feature=youtu.be
Since the crossroad gets signalized anyway I wonder if there is a big benefit to that extra bridged-ramp. I also wonder how difficult pedestrian crossings would be in those two unsignalized corners: they either cross a free right or free left turn. In my head it's moving close to a split diamond, but with a wide median rather than two cross roads. (or like a "town center" + freeway) That would result in four two-phase signals.
(https://upload.wikimedia.org/wikipedia/commons/thumb/5/57/Split_diamond_interchange.svg/290px-Split_diamond_interchange.svg.png)
Quote from: kphoger on October 24, 2018, 03:04:35 PM
I stumbled upon a DDI in Mexico while I was looking. I didn't realize any DDIs existed there.
Was it this one? https://www.google.com/maps/@19.6238016,-99.1925003,200m/data=!3m1!1e3
Slightly different looking than the ones built in the US!
Quote from: johndoe on October 26, 2018, 09:47:21 AM
Quote from: kphoger on October 24, 2018, 03:04:35 PM
I stumbled upon a DDI in Mexico while I was looking. I didn't realize any DDIs existed there.
Was it this one? https://www.google.com/maps/@19.6238016,-99.1925003,200m/data=!3m1!1e3
Slightly different looking than the ones built in the US!
From what I can see, there is absolutely zero signage indicating that the directions cross over. And the eastern crossover isn't even signalized!
I wonder what the crash rate there is, or how many drivers go the wrong way on the overpass.
Quote from: US 89 on October 26, 2018, 11:00:39 AM
Quote from: johndoe on October 26, 2018, 09:47:21 AM
Quote from: kphoger on October 24, 2018, 03:04:35 PM
I stumbled upon a DDI in Mexico while I was looking. I didn't realize any DDIs existed there.
Was it this one? https://www.google.com/maps/@19.6238016,-99.1925003,200m/data=!3m1!1e3
Slightly different looking than the ones built in the US!
From what I can see, there is absolutely zero signage indicating that the directions cross over. And the eastern crossover isn't even signalized!
I wonder what the crash rate there is, or how many drivers go the wrong way on the overpass.
Holy fuckarooni, Batman! The only signage I see is this:
https://goo.gl/maps/LobQdTKNVys
https://goo.gl/maps/8cBVo7o7tzt
Quote from: Brandon on October 26, 2018, 12:05:20 PM
Quote from: US 89 on October 26, 2018, 11:00:39 AM
Quote from: johndoe on October 26, 2018, 09:47:21 AM
Quote from: kphoger on October 24, 2018, 03:04:35 PM
I stumbled upon a DDI in Mexico while I was looking. I didn't realize any DDIs existed there.
Was it this one? https://www.google.com/maps/@19.6238016,-99.1925003,200m/data=!3m1!1e3
Slightly different looking than the ones built in the US!
From what I can see, there is absolutely zero signage indicating that the directions cross over. And the eastern crossover isn't even signalized!
I wonder what the crash rate there is, or how many drivers go the wrong way on the overpass.
Holy fuckarooni, Batman! The only signage I see is this:
https://goo.gl/maps/LobQdTKNVys
https://goo.gl/maps/8cBVo7o7tzt
How did I miss those? :-D
I love that second one. Can I go to the right of the gore point sign or not? :pan:
Quote from: US 89 on October 26, 2018, 12:18:28 PM
Quote from: Brandon on October 26, 2018, 12:05:20 PM
Quote from: US 89 on October 26, 2018, 11:00:39 AM
Quote from: johndoe on October 26, 2018, 09:47:21 AM
Quote from: kphoger on October 24, 2018, 03:04:35 PM
I stumbled upon a DDI in Mexico while I was looking. I didn't realize any DDIs existed there.
Was it this one? https://www.google.com/maps/@19.6238016,-99.1925003,200m/data=!3m1!1e3
Slightly different looking than the ones built in the US!
From what I can see, there is absolutely zero signage indicating that the directions cross over. And the eastern crossover isn't even signalized!
I wonder what the crash rate there is, or how many drivers go the wrong way on the overpass.
Holy fuckarooni, Batman! The only signage I see is this:
https://goo.gl/maps/LobQdTKNVys
https://goo.gl/maps/8cBVo7o7tzt
How did I miss those? :-D
I love that second one. Can I go to the right of the gore point sign or not? :pan:
Quote from: Brandon on October 26, 2018, 12:05:20 PM
Quote from: US 89 on October 26, 2018, 11:00:39 AM
Quote from: johndoe on October 26, 2018, 09:47:21 AM
Quote from: kphoger on October 24, 2018, 03:04:35 PM
I stumbled upon a DDI in Mexico while I was looking. I didn't realize any DDIs existed there.
Was it this one? https://www.google.com/maps/@19.6238016,-99.1925003,200m/data=!3m1!1e3
Slightly different looking than the ones built in the US!
From what I can see, there is absolutely zero signage indicating that the directions cross over. And the eastern crossover isn't even signalized!
I wonder what the crash rate there is, or how many drivers go the wrong way on the overpass.
Holy fuckarooni, Batman! The only signage I see is this:
https://goo.gl/maps/LobQdTKNVys
https://goo.gl/maps/8cBVo7o7tzt
Technically there is
this (vague) (advance) signage (https://goo.gl/maps/cFx18aqiivC2) indicating a veer to the left, but only on one approach.
Just found another DDI in Mexico. How did I not realize these existed down there?
https://goo.gl/maps/aSbssirX4fB2 (https://goo.gl/maps/aSbssirX4fB2)
Quote from: kphoger on October 26, 2018, 03:12:57 PM
Just found another DDI in Mexico. How did I not realize these existed down there?
https://goo.gl/maps/aSbssirX4fB2 (https://goo.gl/maps/aSbssirX4fB2)
Holy head-on collisions! How can you tell it's a DDI from the 2017 Google Street View!?! 2012 has some signage, but 2017 completely lacks signage.
Who needs complexity and stop lights when a roundabout will work just fine in a similar layout ... https://www.google.com/maps/@39.9419367,-86.0187932,19.19z
https://www.youtube.com/watch?v=r_fL4rqvZG0
https://www.youtube.com/watch?v=yG1ittH-seI
Something tells me that will perform better than the typical multi-lane roundabout. Very Australian/Kiwi design (not British, as it's not large enough nor would the entrance ramps have chicanes).
Florida is planning several more DDI's including one at I-75 & Martin Luther King Jr. Blvd near Tampa. However, the "lipstick interchange" as i'm affectionately calling it could fit in the same amount of ROW as the proposed DDI.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.tampabay.com%2Fassets%2Fjpg%2FHI427521.JPG&hash=3d27380f7ee4e176304b3754c8c3270d860f1e23)
(https://i.imgur.com/ewcuH1P.jpg)
^Just like a Town Center Intersection (TCI) you can have commercial development in the median where the arterial street branches out. Here's an example of a gas station at a TCI in California:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi478.photobucket.com%2Falbums%2Frr144%2Ftradephoric%2FTransportation%2520Pictures%2FRandom%2Funtitled7_zps97927a27.jpg&hash=2fcb65095efd7d07f0af7597c9f8ff2d958c0d03) (http://s478.photobucket.com/user/tradephoric/media/Transportation%20Pictures/Random/untitled7_zps97927a27.jpg.html)
Quote from: johndoe on October 26, 2018, 09:47:21 AM
Since the crossroad gets signalized anyway I wonder if there is a big benefit to that extra bridged-ramp. I also wonder how difficult pedestrian crossings would be in those two unsignalized corners: they either cross a free right or free left turn. In my head it's moving close to a split diamond, but with a wide median rather than two cross roads. (or like a "town center" + freeway) That would result in four two-phase signals.
(https://upload.wikimedia.org/wikipedia/commons/thumb/5/57/Split_diamond_interchange.svg/290px-Split_diamond_interchange.svg.png)
The interchange does closely resemble a split diamond or volleyball interchange. Here is an interchange in Edmonton that closely resembles the interchange i was picturing:
https://www.google.com/maps/@53.4805077,-113.4935405,468m/data=!3m1!1e3
...and just a mile to the west is this Volleyball (or split diamond) interchange. By the way is there a technical difference between a split diamond interchange and a volleyball interchange or are they essentially the same thing?
https://www.google.com/maps/@53.4828018,-113.5169789,234m/data=!3m1!1e3
Quote from: tradephoric on October 29, 2018, 10:06:23 AM
By the way is there a technical difference between a split diamond interchange and a volleyball interchange or are they essentially the same thing?
They are the same thing.
kurumi came up with the term. See below, from
his website (http://www.kurumi.com/roads/interchanges/volleyball.html):
Quote from: kurumi.com – Interchanges: Volleyball
This interchange is better known as the 3-level diamond or split-level diamond. The term "volleyball interchange," one of my few contributions to colloquial English, will get you blank stares at a job interview, but a smile of recognition among many road fans.
Split diamond interchanges are pretty unusual in WA, although one does exist in Spokane: https://goo.gl/JA2htC
Weirdly, the double left turns at this interchange permit turns on red, but the single lefts do not. The difference is that, the NTOR restriction is for traffic turning left across off-ramp traffic, rather than
across NB or SB arterial traffic.
Operationally, I don't see that many differences between split diamonds and signalized roundabout interchanges. The video posted on the last page from Indiana shows what is effectively a split diamond roundabout:
Quote from: cjw2001 on October 26, 2018, 09:17:45 PM
https://www.youtube.com/watch?v=r_fL4rqvZG0
Split-level diamond = volleyball.
Split diamond ≠ split level diamond.
Split diamond = elongated diamond and is the general term for diamond interchanges where the ramps are "split" between two or more cross-roadways. Jake: the Thor St/Freya St interchange on I-90 (Exit 283B) is a better Spokane example. Other examples include I-494 MN Exit 65 (5th Ave & 7th Ave), I-55 MS Exit 107 (Colony Park Blvd & Madison Ave), and I-664 VA Exit 4 (Roanoke Ave & Chestnut Ave).
Quote from: froggie on October 29, 2018, 03:32:09 PM
Jake: the Thor St/Freya St interchange on I-90 (Exit 283B) is a better Spokane example.
I was going to post it, but it does not involve any freeway ramps, only frontage roads (although it once did -- westbound exit). The Exit 287 interchange at least involves two freeway ramps.
Quote from: jakeroot on October 29, 2018, 03:17:38 PM
Split diamond interchanges are pretty unusual in WA, although one does exist in Spokane: https://goo.gl/JA2htC
That's a great example of a freeway connecting to a one-way couplet. It seems like these types of interchanges would naturally exist along one-way grids but i'm surprised how few examples i could find.
Quote from: tradephoric on October 29, 2018, 03:58:08 PM
Quote from: jakeroot on October 29, 2018, 03:17:38 PM
Split diamond interchanges are pretty unusual in WA, although one does exist in Spokane: https://goo.gl/JA2htC
That's a great example of a freeway connecting to a one-way couplet. It seems like these types of interchanges would naturally exist along one-way grids but i'm surprised how few examples i could find.
Split (not split level) diamond interchange at a one-way couplet near me in Wichita:
I-135 & 1st & 2nd Streets (https://goo.gl/maps/NLc4KoYMbVr)
Quote from: jakeroot on October 29, 2018, 03:35:06 PM
Quote from: froggie on October 29, 2018, 03:32:09 PM
Jake: the Thor St/Freya St interchange on I-90 (Exit 283B) is a better Spokane example.
I was going to post it, but it does not involve any freeway ramps, only frontage roads (although it once did -- westbound exit). The Exit 287 interchange at least involves two freeway ramps.
Whether the ramps directly tie into frontage roads or not doesn't matter. Exit 283B is still fundamentally a split-diamond.
Quote from: froggie on October 29, 2018, 05:08:44 PM
Quote from: jakeroot on October 29, 2018, 03:35:06 PM
Quote from: froggie on October 29, 2018, 03:32:09 PM
Jake: the Thor St/Freya St interchange on I-90 (Exit 283B) is a better Spokane example.
I was going to post it, but it does not involve any freeway ramps, only frontage roads (although it once did -- westbound exit). The Exit 287 interchange at least involves two freeway ramps.
Whether the ramps directly tie into frontage roads or not doesn't matter. Exit 283B is still fundamentally a split-diamond.
I don't disagree. I was just trying to find an example where the frontage roads were not part of a local grid system, rather just natural extensions of an off-ramp. Exit 283B could not have been easily built as anything but a split diamond, however Exit 287 very easily could have been built as a regular diamond, or something else.
Quote from: tradephoric on October 25, 2018, 05:06:34 PM
I created a model of the interchange in SYNCHO.
https://www.youtube.com/watch?v=2IZ3lzQ3ISA&feature=youtu.be
Below is a slight modification to the model that includes loop ramps. The advantage is it takes up less ROW and there are fewer pedestrian crossing along the arterial. The disadvantage is it increases driver delay quite significantly for traffic exiting the freeway wanting to continue right on the arterial (much farther distance traveled). Still, the operational advantages of either of these models would blow the DDI out of the water.
https://www.youtube.com/watch?v=HFlo90vZxmM
Lipstick on a pig parclo B4?
Quote from: NE2 on November 01, 2018, 07:22:07 AM
Lipstick on a pig parclo B4?
Since i called it the "lipstick" interchange i feel like i was setting myself up for that! One of the knocks against any Parclo is the amount of ROW they take up. But with a Milwaukee interchange it can once again be quite compact....
(https://www.roadtraffic-technology.com/wp-content/uploads/sites/17/2017/10/5l-image-10.jpg)
Not to mention the Milwaukee B minimizes travel times through the interchange when compared to the DDI, Diamond, Milwaukee A, Parclo B, or Synchronized interchange (i'm sure you could add SPUI into the list but this particular study didn't analyze the SPUI). Notice how poorly the DDI is for through traffic on the arterial? It's even worse than the lowly diamond interchange...
(https://i.imgur.com/Tvo2srH.png)
https://digitalcommons.wayne.edu/cgi/viewcontent.cgi?article=2844&context=oa_dissertations
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgflip.com%2F2lhav3.jpg&hash=6d26f934d431a91fad55d849e393cc86b607719e)
Quote from: tradephoric on November 01, 2018, 09:45:51 AM
Notice how poorly the DDI is for through traffic on the arterial? It's even worse than the lowly diamond interchange...
Has anyone ever claimed otherwise? I thought everyone knew all along that through-traffic on the arterial was going to be sacrificing efficiency for the sake of the other movements.
Quote from: kphoger on November 01, 2018, 12:04:10 PM
Has anyone ever claimed otherwise? I thought everyone knew all along that through-traffic on the arterial was going to be sacrificing efficiency for the sake of the other movements.
The problem is the DDI has longer travel times for other movement compared to the Milwaukee B. I could understand nearly 50 second longer travel times for arterial traffic along the DDI if it meant a dramatic drop in travel times for the other movements... but that's not what you see.
(https://i.imgur.com/Tvo2srH.png)
According to the study the DDI has worse travel times for every movement compared to the Milwaukee B except for the "Right turn from freeway to arterial" movement (where they are basically the same). I question if delay is lower at a DDI for that movement since at many DDI's you are restricted from making a simple right on red coming off the freeway. Here is a streetview of the newly constructed University Parkway DDI in Florida. To me "NO TURN ON RED" equals DELAY.
(https://i.imgur.com/WexrA24.png)
https://www.google.com/maps/@27.3883793,-82.4468742,3a,75y,55.35h,87.02t/data=!3m6!1e1!3m4!1sQHH9K4LBB1Y0PATz1sf3Qw!2e0!7i13312!8i6656
Quote from: tradephoric on November 01, 2018, 12:29:38 PM
Quote from: kphoger on November 01, 2018, 12:04:10 PM
Has anyone ever claimed otherwise? I thought everyone knew all along that through-traffic on the arterial was going to be sacrificing efficiency for the sake of the other movements.
The problem is the DDI has longer travel times for other movement compared to the Milwaukee B. I could understand nearly 50 second longer travel times for arterial traffic along the DDI if it meant a dramatic drop in travel times for the other movements... but that's not what you see.
According to the study the DDI has worse travel times for every movement compared to the Milwaukee B except for the "Right turn from freeway to arterial" movement (where they are basically the same).
Sorry, I meant that people aren't generally comparing a DDI to a Milwaukee B interchange, because they've never heard of a Milwaukee B interchange. Also, DDIs tend to get built because the state only wants to install one bridge, and that advantage goes out the window with a Milwaukee B interchange. It seems to me that DDIs are installed as a cheap-ish upgrade from a standard diamond interchange. And, if you look at that chart, a DDI does better than a diamond on every movement
except through-traffic on the arterial–and even that's just barely worse.
It's one thing to build a DDI to replace an existing Diamond where you don't have the space to build anything else. It's entirely different to build a supersized DDI where a more efficient interchanges could fit. Does this look like a cheap-ish upgrade from a standard diamond interchange to you?
(https://www.gannett-cdn.com/-mm-/84d36a0d65abc19d43ee214b293423386fef9cf5/c=3-0-1474-831/local/-/media/2017/08/09/Brevard/Brevard/636378803418007586-FNP0912DivergingDiamond001.jpg)
The Split Milwaukee B interchange wouldn't fit everywhere, but when Florida decides to build these massive DDI's it suddenly becomes an option. Below is the required footprint of the Split Milwaukee B interchange juxtaposed over the University Parkway DDI in Florida. If anything the Split Milwaukee B would take up less ROW than that massive DDI they built... and there would be a lot less delay for nearly every turning movement.
(https://i.imgur.com/NttjPFV.png)
Quote from: tradephoric on November 01, 2018, 03:26:52 PM
It's one thing to build a DDI to replace an existing Diamond where you don't have the space to build anything else. It's entirely different to build a supersized DDI where a more efficient interchanges could fit. Does this look like a cheap-ish upgrade from a standard diamond interchange to you?
(https://www.gannett-cdn.com/-mm-/84d36a0d65abc19d43ee214b293423386fef9cf5/c=3-0-1474-831/local/-/media/2017/08/09/Brevard/Brevard/636378803418007586-FNP0912DivergingDiamond001.jpg)
The Split Milwaukee B interchange wouldn't fit everywhere, but when Florida decides to build these massive DDI's it suddenly becomes an option. Below is the required footprint of the Split Milwaukee B interchange juxtaposed over the University Parkway DDI in Florida. If anything the Split Milwaukee B would take up less ROW than that massive DDI they built... and there would be a lot less delay for nearly every turning movement.
(https://i.imgur.com/NttjPFV.png)
All I see in that first picture is pavement, barriers, sign gantries and stoplights. Not knowing how much r/o/w they had to work with, I couldn't say how cheap-ish that looks to me. What I do
not see in that picture are any additional bridges, and I'd say that has a lot of bearing on the price tag.
With the arterial passing underneath the freeway, it's going to be two bridges no matter what–one for each carriageway of the freeway. Changing that to a "lipstick interchange" would increase that number by at least two more bridges, probably four. That is a significant increase in construction cost. No matter how you slice it, a DDI has a lot less bridge work than the "lipstick".
Quote from: kphoger on November 01, 2018, 03:38:41 PM
What I do not see in that picture are any additional bridges, and I'd say that has a lot of bearing on the price tag.
Judging by the length of the overpasses corresponding exactly to the width of the roadway, the overpasses were rebuilt to accommodate the new width of the arterial. Parclo designs would have likely required wider overpasses but a narrower arterial and shorter overpasses.
I don't know how closely related this is, but check out the junction of TX-136 & TX-207 (https://goo.gl/maps/xVHThxeR6zG2).
I like the roundabout option for the intersection of US 75 and US 82 in Sherman, TX. All traffic exiting from one to the other must negotiate the frontage roads paralleling each. Right turns are easy, left turns mean hitting 3 traffic lights. A roundabout setup would eliminate the need for signals.
(My preference for this particular interchange is a stack with flyovers, but this is a road board, not a comedy board.)
Quote from: Road Hog on November 26, 2018, 01:22:22 AM
I like the roundabout option for the intersection of US 75 and US 82 in Sherman, TX. All traffic exiting from one to the other must negotiate the frontage roads paralleling each. Right turns are easy, left turns mean hitting 3 traffic lights. A roundabout setup would eliminate the need for signals.
(My preference for this particular interchange is a stack with flyovers, but this is a road board, not a comedy board.)
Volleyball.
Quote from: kphoger on November 24, 2018, 05:15:10 PM
I don't know how closely related this is, but check out the junction of TX-136 & TX-207 (https://goo.gl/maps/xVHThxeR6zG2).
There are a few other examples of this interchange that i know of but not nearly as compact as your example:
https://www.google.com/maps/@42.3711408,-71.269529,463m/data=!3m1!1e3
https://www.google.com/maps/@42.5937032,-70.9634984,919m/data=!3m1!1e3
Here's my interpretation of the interchange on SYNCHRO:
https://www.youtube.com/watch?v=yplEKcvOk5o
Quote from: NE2 on October 24, 2018, 03:27:29 PM
A mirror image with weaving instead of lights, MA 128 at US 20: https://www.google.com/maps/@42.3708793,-71.2696918,626m/data=!3m1!1e3
Somewhat close, I-270 at MO 100: https://www.google.com/maps/@38.6026606,-90.4503011,662m/data=!3m1!1e3
I was going to post the first one lol
iPhone
what is SYNCHRO and where can i get it? im interested in these types of illistrations.
Quote from: MCRoads on November 27, 2018, 05:33:49 PM
what is SYNCHRO and where can i get it? im interested in these types of illistrations.
Synchro Studio is a software suite that includes the Simtraffic program. It costs $3299 for a single-machine licence.
No idea if
Trade acquired it some other way.
Synchro does have a few issues that I've noticed. It's not "variable" enough, from what I've seen. For example, not all drivers turn right on red (or via a slip lane) when the closest lane is open, instead waiting until the closest two lanes are open (safety perception). Cars in Synchro seem to be "ballsier" than real drivers.
Also (this is my bigger gripe), it assumes that drivers at permissive turns take the same turning path as drivers with protected turns. In my experience, drivers at permissive turns take sharper turns, with the turn taking place further out into the intersection. This is because the driver is yielding usually from a point other than the stop line. Protected turns are often more "sweeping", occurring immediately after the stop line rather than from a point beyond it.
Why is this important? The waiting point for turning drivers is usually the point right before the turning and non-turning paths overlap. If traffic waits beyond the stop line, that point is potentially far enough beyond the stop line for one, two, or more cars to turn after the red light comes up. Synchro has no way of calculating this because it does not permit such behaviour. From my perspective, that is a serious number of cars that are not being considered when calculating capacity, especially left turn capacity.
To add on to my post above, here's an intersection in Vancouver where we can see cars doing something that Synchro does not understanding...waiting beyond the stop line.
The blue line is the path for protected-left traffic. The fuchsia line is permissive-left traffic. Note they are two different paths.
(https://i.imgur.com/UHNJTLB.png)
ah. Thank you for the info. somhow i doubt im going to get synchro. any other programs that are free to use, but function the same as (if not better than) synchro?
Sorry to derail the topic.