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[JKRhodes]

I'm trying to understand the rationale behind this "hybrid SPUI" at PDN and 2nd Street. There certainly doesn't seem to be any savings in ROW vs a standard SPUI. If anything it appears to take up more:

https://goo.gl/maps/NAQ6UUpRP5dErPkX7

[Plutonic Panda]

And it has left exits yuck

[JKRhodes]

And it has left exits yuck

My main gripe. Upon further study it seems  they may have designed it that way in order to buy a few extra car lengths of queue space for SB 2nd street approaching El Pueblo. Still, very odd. Based on each iteration of street view it doesn't look heavily traveled enough to routinely back up into the SPUI, and there are pylons to eliminate weaving. So a standard SPUI would have probably served its purpose just fine.

[abqtraveler]

And it has left exits yuck

My main gripe. Upon further study it seems  they may have designed it that way in order to buy a few extra car lengths of queue space for SB 2nd street approaching El Pueblo. Still, very odd. Based on each iteration of street view it doesn't look heavily traveled enough to routinely back up into the SPUI, and there are pylons to eliminate weaving. So a standard SPUI would have probably served its purpose just fine.

Using historicaerials.com to view the PDN/2nd Street interchange, it was previously an at-grade intersection that was converted to the current interchange some time between 1991 and 1996. My theory into why they built it the way they did is they had to keep the existing intersection open and unobstructed while construction of the interchange proceeded. You'll notice that the EB and WB left-hand offramps both intersect 2nd Street at the same point where the previous at-grade intersection used to lie. From that, it looks like they built the overpasses outside of the existing intersection to keep the intersection and its approaches unimpeded during construction. When the overpasses were completed, it would be relatively easy to shift PDN traffic onto the new overpasses, and then convert the old PDN roadway to the offramps you see today. 

It's not necessarily how I would have built the interchange, but I can see the logic in the design...it was all about maintaining traffic flow through the intersection while the interchange was being built. 

[triplemultiplex]

Using historicaerials.com to view the PDN/2nd Street interchange, it was previously an at-grade intersection that was converted to the current interchange some time between 1991 and 1996. My theory into why they built it the way they did is they had to keep the existing intersection open and unobstructed while construction of the interchange proceeded. You'll notice that the EB and WB left-hand offramps both intersect 2nd Street at the same point where the previous at-grade intersection used to lie. From that, it looks like they built the overpasses outside of the existing intersection to keep the intersection and its approaches unimpeded during construction. When the overpasses were completed, it would be relatively easy to shift PDN traffic onto the new overpasses, and then convert the old PDN roadway to the offramps you see today.

This has always been my assumption as well.  It was the result of someone's poor planning in terms of construction staging.
Everyone knows that to build a single point interchange under traffic, you rough in the ramps first, shift the traffic over to the ramps, and then build your bridges in the 'median'.  Once the bridges are done, traffic is shifted there, then you clean up the ramps and voila: completed SPUI.

[thenetwork]

A Shocker crossing into the state On US-550 today ...

After nearly 2 years, they FINALLY got around  Is to putting a "Welcome to New Mexico" sign at the border.

THIS,...coming a few weeks after a.FULL resurfacing of US-550 between Aztec and Bloomfield.

Still nothing on US‐491 South yet...

[DJStephens]

And it has left exits yuck

My main gripe. Upon further study it seems  they may have designed it that way in order to buy a few extra car lengths of queue space for SB 2nd street approaching El Pueblo. Still, very odd. Based on each iteration of street view it doesn't look heavily traveled enough to routinely back up into the SPUI, and there are pylons to eliminate weaving. So a standard SPUI would have probably served its purpose just fine.

Using historicaerials.com to view the PDN/2nd Street interchange, it was previously an at-grade intersection that was converted to the current interchange some time between 1991 and 1996. My theory into why they built it the way they did is they had to keep the existing intersection open and unobstructed while construction of the interchange proceeded. You'll notice that the EB and WB left-hand offramps both intersect 2nd Street at the same point where the previous at-grade intersection used to lie. From that, it looks like they built the overpasses outside of the existing intersection to keep the intersection and its approaches unimpeded during construction. When the overpasses were completed, it would be relatively easy to shift PDN traffic onto the new overpasses, and then convert the old PDN roadway to the offramps you see today. 

It's not necessarily how I would have built the interchange, but I can see the logic in the design...it was all about maintaining traffic flow through the intersection while the interchange was being built.

Was under the impression it dated from late eighties.   Just illustrates the non-standard, design-regressive, weird stuff that has been allowed to have been built in this state.   If mid nineties, could  very well have been an excretion from Pete Rahn's school of thought.   

[abqtraveler]

NMDOT's new website just went live. The URL is https://www.dot.nm.gov/

[CanesFan27]

Not all roadtrips are long drives - New Mexico Highway 28 is a great example.  History, scenery, and a lot of pecans.  Come along for the ride.

https://www.gribblenation.org/2022/01/new-mexico-route-28.html

[oscar]

NMDOT's new website just went live. The URL is https://www.dot.nm.gov/

NMDOT still hasn't updated at least its main posted route log since 2010. I just use NMDOT's online Roadway Functional Class map to get the latest, though the "latest" may be a few years old.