This interchange seems extremely simple, but it seems like this isn't found anywhere else.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fmaps.googleapis.com%2Fmaps%2Fapi%2Fstaticmap%3Fcenter%3D42.734500%2C-71.204000%26amp%3Bzoom%3D15%26amp%3Bsize%3D400x400&hash=19ebe9aaaf6a267f3686def8a36a8d44cb1b0f1f)
This image uses the Google Maps API.
(For reference, this is in Massachusetts. I-93 is marked, and the dashed line at the top right corner is the MA/NH border.)
None that I know of. Nor is such a design encouraged due to the weaving issues caused by the two ramps merging and diverging.
SR 60 at SR 589 in Tampa was a squished version with left exits: http://ufdc.ufl.edu/UF00071755/00028/14x
There are probably some in countries like the UK that have a bunch of roundabouts.
I'm sure weaving occurs in practice but theoretically there is only 1 lane between ramp converge/diverge. The ramp from 93 SB is supposed to yield to the ramp from 213 WB...
But I am also drawing a blank on anywhere that does this in a simplistic interchange like that...
Quote from: NE2 on April 25, 2016, 04:27:18 PM
There are probably some in countries like the UK that have a bunch of roundabouts.
Apropos this, the M32 at M4 interchange (https://www.google.com/maps/place/M32,+Bristol,+UK/@51.512706,-2.5194424,17.62z/data=!4m2!3m1!1s0x4871902a8cd728cf:0xb4e2becc4dba6fd8) is effectively like this (although obviously a lower-speed affair, being a roundabout). More surprisingly, M5 at M50 (https://www.google.com/maps/place/M32,+Bristol,+UK/@52.0476631,-2.1365426,18.14z/data=!4m2!3m1!1s0x4871902a8cd728cf:0xb4e2becc4dba6fd8) isn't (although it was downgraded from a free-flow interchange
to provide access to/from the south for no particular reason, apparently).
One overpass and the weaving, etc is gone. Seems like the 213 ramps were done by the state on the cheap.
Mass. has a love affair with rotaries. This is as close as you can get to a full rotary with a freeway-to-freeway connection.
Quote from: Mapmikey on April 25, 2016, 04:28:49 PM
I'm sure weaving occurs in practice but theoretically there is only 1 lane between ramp converge/diverge. The ramp from 93 SB is supposed to yield to the ramp from 213 WB...
Are you sure that's correct? It seems counterintuitive to me. If it were a cloverleaf weave, entering traffic (from 213 WB) would yield to exiting traffic (from 91 SB).
Quote from: Kacie Jane on April 26, 2016, 04:33:44 PM
Quote from: Mapmikey on April 25, 2016, 04:28:49 PM
I'm sure weaving occurs in practice but theoretically there is only 1 lane between ramp converge/diverge. The ramp from 93 SB is supposed to yield to the ramp from 213 WB...
Are you sure that's correct? It seems counterintuitive to me. If it were a cloverleaf weave, entering traffic (from 213 WB) would yield to exiting traffic (from 91 SB).
I think the interchange is meant to resemble a typical rotary, hence the yield signs for traffic exiting 93 SB: https://goo.gl/mTbVkE.
One was planned in the UK exactly like the I-93 example in the original post. This map is from 1970 but it was eventually built 20 years later (https://www.google.co.uk/maps/@52.5755847,-2.0468682,738m/data=!3m1!1e3) as a roundabout.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.speedcam.uk%2Fd70%2Fbilston.jpg&hash=986f411d83ddd790ce7a0b531f1d5e35f5e12144)
There is something similar in spirit, though a lot more complicated, going on here:
https://www.google.com/maps/@40.5266846,-74.3370103,16z
Do you mind if you can clarify the movements? I can't quite make heads or tails about it.
I'm not (https://www.google.com/maps/place/Indiana+Toll+Rd,+Indiana/@41.5915781,-87.3058814,16.25z/data=!4m2!3m1!1s0x8816ce7b334203bb:0xf971c39a994de20f') quite sure if that's what you're looking for, but I'll see if I can't dig up something more of what you're asking for.
Close enough.
https://goo.gl/maps/W8nRdL7T2PN2
Quote from: Kacie Jane on April 26, 2016, 04:33:44 PM
Quote from: Mapmikey on April 25, 2016, 04:28:49 PM
I'm sure weaving occurs in practice but theoretically there is only 1 lane between ramp converge/diverge. The ramp from 93 SB is supposed to yield to the ramp from 213 WB...
Are you sure that's correct? It seems counterintuitive to me. If it were a cloverleaf weave, entering traffic (from 213 WB) would yield to exiting traffic (from 91 SB).
As someone who has driven through this dozens of times, I can confirm the traffic entering from 93 S/B is supposed to yield. Most don't, but that's the traffic obligated to yield entering.
Quote from: lordsutch on April 25, 2016, 04:52:34 PM
Quote from: NE2 on April 25, 2016, 04:27:18 PM
There are probably some in countries like the UK that have a bunch of roundabouts.
Apropos this, the M32 at M4 interchange (https://www.google.com/maps/place/M32,+Bristol,+UK/@51.512706,-2.5194424,17.62z/data=!4m2!3m1!1s0x4871902a8cd728cf:0xb4e2becc4dba6fd8) is effectively like this (although obviously a lower-speed affair, being a roundabout). More surprisingly, M5 at M50 (https://www.google.com/maps/place/M32,+Bristol,+UK/@52.0476631,-2.1365426,18.14z/data=!4m2!3m1!1s0x4871902a8cd728cf:0xb4e2becc4dba6fd8) isn't (although it was downgraded from a free-flow interchange to provide access to/from the south for no particular reason, apparently).
I've driven through the M32/M4 one. Once upon a time it was a full roundabout, but by 2007 they'd blocked off the southwest side and it's now essentially a teardrop (M4 traffic cannot use it to reverse direction). If you look at the satellite view you'll see the closed-off piece.
(Edited to fix typo)
Quote from: lordsutch on April 25, 2016, 04:52:34 PMMore surprisingly, M5 at M50 (https://www.google.com/maps/place/M32,+Bristol,+UK/@52.0476631,-2.1365426,18.14z/data=!4m2!3m1!1s0x4871902a8cd728cf:0xb4e2becc4dba6fd8) isn't (although it was downgraded from a free-flow interchange to provide access to/from the south for no particular reason, apparently).
They removed the free-flow as 1960-spec trumpet loop was dangerous (capsized lorries galore), and the weaving between the sliproads for the services and the junction was bad.
The south-facing sliproads of the service area merge into the north-facing sliproads of the junction, hence why the junction doesn't look like this sort of one with a teardrop shape.
The M27/M271 roundabout was proposed to be a modified one (southern side of the roundabout closing, just like the M4/M32 one), but that was so controversial that the proposal was never formalised.