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Diverging Diamond Interchange (wikipedia.org)
10 points by mojoe on Oct 12, 2015 | hide | past | favorite | 8 comments

We are getting one here in Naperville, IL. They put out a pretty decent video showing how it will work and what it will look like when they are all done.



Utah has one. I think they are more common when the non freeway road has very high levels of traffic.

An even more efficient interchange is the roundabout interchange https://en.wikipedia.org/wiki/Roundabout_interchange

The only problems with the roundabout interchange are that you need two different bridges spaced a distance apart which can add construction costs and they require more area than a standard interchange, although about the same as a clover leaf.

Minnesota has one near the airport (http://www.dot.state.mn.us/funding/projects/bloomington.html) that also has a light rail line running through it. It seems to work well but is definitely a little alarming the first time you drive through it.

Colorado is putting a diverging diamond interchange in near where I live in Boulder county. Work will be finishing soon and I was wondering if any HNers have had experience with these types of interchanges. It looks very promising, and hopefully drivers will get used to it quickly!

Where I live we have 5-6 and they have worked great. The first time through can be interesting. Years later they are just a normal part of the the road. Everything is clearly marked and lanes are painted brightly. The upgraded intersections are very quick to get through now. In the past you could wait six or seven light cycles before getting through. Now you might have one short stop.

They can be pretty crazy to figure out how to navigate on larger intersections (which have the double diamond plus other intersections in the same area). I can't tell you how many times I've missed my turn and had to take a long way around trying to get through this intersection in Austin: http://www.openstreetmap.org/#map=17/30.23595/-97.82471

Edit: On second thought I'm not entirely sure that is a double-diamond, although I've heard people refer to it as one. It doesn't seem to match up with the wikipedia article, however.

They are all over Missouri. I think the first one in the country was in Springfield, MO (because there is a sign there stating this). They are very confusing the first few times through, but you get used to it.

In the UK, we have something similar to this for most of our motorway junctions, except that the traffic lights are replaced by roundabouts and there's no need for changing sides of the road.

I take it all this extra complexity is just to avoid roundabouts?

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