MN-36 @ CSAH 49: Offset SPUI

[Coelacanth]

http://www.sehinc.com/online/rice36/

I've never seen this interchange configuration before. Certainly not around here.

If you think this layout is weird, check out some of the options they rejected!

[rawmustard]

It certainly looks like they want to evenly space the three signals as much as possible, which the conventional SPUI would not allow. The roundabout option would have been good as long as traffic counts don't rise to a ridiculously high level. And for that stretch of Rice Street, three signalized intersections are preferable to four. The only caveat with the preferred alternative is three bridges instead of one, but the extra space at the County B intersection may be well worth it.

[english si]

In the UK, the powers that be think you can get high volumes of traffic through 'dumbell' interchanges (the roundabout option here) - ridiculously high volumes that they can't take (freeway/expressway style roads of national significance interchanging with motorways, for instance). However I would say that they can support a large enough amount of traffic that this junction wouldn't have gone over capacity with that option. It does depend on the size of the roundabouts and number of lanes and all that, but the plan there looked fine.

This offset SPUI looks a better interchange though, if there's the money to built those extra bridges, they should go for that.

[Revive 755]

^ What about getting pedestrians through a dumbell interchange?  If they want to consider peds, the offset SPUI looks like a good option.

[Zmapper]

The I-225 / Alameda interchange in Aurora, CO is very similar to what is proposed.
http://bit.ly/axyV2Y

[TheStranger]

What intrigues me about the offset SPUI is that at its core it is actually simpler, in some respects, than the regular SPUI - this basically being two semi-directional Y interchanges connected to each other.  The only disadvantage then to the usual SPUI setup comes in forcing traffic from one side of the freeway to have to cross the overpass on all movements, but it offers a much easier intersection for pedestrians to cross.

The more traditional single semi-directional Y-to-surface street setup looks like this:

http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=59th+%26+S,+Sacramento&sll=37.0625,-95.677068&sspn=37.052328,56.513672&ie=UTF8&hq=&hnear=S+St+%26+59th+St,+Sacramento,+California&ll=38.55471,-121.437163&spn=0.008944,0.013797&z=16

http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Olive+Mill+Rd+%26+N+Jameson+Ln,+Montecito&sll=34.419549,-119.634118&sspn=0.018869,0.027595&ie=UTF8&hq=&hnear=N+Jameson+Ln+%26+Olive+Mill+Rd,+Montecito,+Santa+Barbara,+California+93108&ll=34.421616,-119.63982&spn=0.002359,0.003449&z=18

[mapman]

Reminded me of this one -- I guess it's a trumpet SPUI?   

http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Claremont,+CA&sll=37.0625,-95.677068&sspn=50.910968,113.203125&ie=UTF8&hq=&hnear=Claremont,+Los+Angeles,+California&ll=34.12225,-117.694988&spn=0.01311,0.027637&t=h&z=16

[TheStranger]

Reminded me of this one -- I guess it's a trumpet SPUI?   

You know, I recall Kurumi suggesting something rather similar to this design MANY years ago:
http://www.kurumi.com/roads/interchanges/oddities.html

I like it!

In terms of advantages/disadvantages, it's the same deal as the offset SPUI using the semi-directional Y style: much better for pedestrians, but forces a little bit more traffic onto the overpass.

[mgk920]

It reminds me of this one - I-90, interchange 82, in Idaho (Wallace East - ID 4):

http://maps.google.com/?ie=UTF8&ll=47.472634,-115.916684&spn=0.008441,0.021973&t=h&z=16

Mike