Does this interchange type exist anywhere else?

[hotdogPi]

This interchange seems extremely simple, but it seems like this isn't found anywhere else.



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.)

[froggie]

None that I know of.  Nor is such a design encouraged due to the weaving issues caused by the two ramps merging and diverging.

[NE2]

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.

[Mapmikey]

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...

[lordsutch]

There are probably some in countries like the UK that have a bunch of roundabouts.

Apropos this, the M32 at M4 interchange is effectively like this (although obviously a lower-speed affair, being a roundabout). More surprisingly, M5 at M50 isn't (although it was downgraded from a free-flow interchange to provide access to/from the south for no particular reason, apparently).

[Sykotyk]

One overpass and the weaving, etc is gone. Seems like the 213 ramps were done by the state on the cheap.

[shadyjay]

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.

[Kacie Jane]

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).

[jakeroot]

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.

[Truvelo]

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 as a roundabout.

[bzakharin]

There is something similar in spirit, though a lot more complicated, going on here:
https://www.google.com/maps/@40.5266846,-74.3370103,16z

[noelbotevera]

Do you mind if you can clarify the movements? I can't quite make heads or tails about it.

I'm not 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.

[webfil]

Close enough.

https://goo.gl/maps/W8nRdL7T2PN2

[SectorZ]

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.

[1995hoo]

There are probably some in countries like the UK that have a bunch of roundabouts.

Apropos this, the M32 at M4 interchange is effectively like this (although obviously a lower-speed affair, being a roundabout). More surprisingly, M5 at M50 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)

[english si]

More surprisingly, M5 at M50 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.