DDI-Double Diamond Interchanges

edit:Title should read "Diverging Diamond Interchange"

Been out a year or two; but is starting to pop up around the country; (along with roundabouts; which I like by the way; no waiting for a malfunctioning light)
1.they claim it reduces left turn backups and jams
2.says there are 14 points of conflicts vs 26 points of conflicts with the old style
3.you can't say "someone turned left in front of me"
4.feels like your in England for a short distance; ha ha
5.it's called a DDI, diverging diamond interchange; but I call it the "spagetti bowl"
[video=youtube;BNGXHKpRcr8]https://www.youtube.com/watch?v=BNGXHKpRcr8&list=WL&index=95[/video]

I know GR and they are planning DDI here in PHX too. We have a horrible problem with wrong way drivers at the freeways. I see this as only adding to the confusion and the problem. Engineers say it will reduce the wrong way driver.

Our biggest problem with wrong way drivers is their drinking problem.
The DDI idea looks innovative....time and experience will tell.

We have one here that they installed 2 years ago. I was very sceptical when I first read about it, but it has greatly improved traffic flow. This was put in after a very large hospital was built on the north end of town and everybody was trying to turn and go south.

The problem though is that we have many older people and out of town people that come to this hospital are very confused when they first encounter the overpass. Once in a while we do have a accident where somebody tried staying on the right side of the bridge.

I use this overpass every morning and afternoon to enter and exit the freeway. It does cut down on the possible areas of contact, or at least make them more manageable. All in all it has been a success.

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There's a DDI at McCaslin over Hwy 36 in Superior. https://www.google.com/maps/@39.9578204,-105.1656572,17.89z

I rode over it a month or two ago down McCaslin and was 'confused' by it--I thought it very strange for through-traffic and I noticed there seemed to be a lot of vehicles in queue at each light (was slow to get through).

Using your GPS to get through one of those would be a whole lot of fun if its maps aren't up to date.

Navigating a DDI could be in interesting YT video. Where's Capt. Crash when we need him? :grin:

We have one of those in Lexington on Harrodsburg Rd. at New Circle. Drivers seem to be used to it and it has improved traffic flow. I had a fender bender at that same location in 1985 so I was glad to see it.

Traffic flow improvement schemes are 100% user dependent.
Simple example is the traffic circle. This should be an excellent cure for 4-way stop sign runners. But, these same people use the 'roundabout' and ignore the yield signs and will not use their signals. Lots of broken plastic along our local circles. I don't see a net gain.

Oldbikefixr said:

Traffic flow improvement schemes are 100% user dependent.
Simple example is the traffic circle. This should be an excellent cure for 4-way stop sign runners. But, these same people use the 'roundabout' and ignore the yield signs and will not use their signals. Lots of broken plastic along our local circles. I don't see a net gain.

Click to expand...

The net gain is that they are fender benders and not the more severe angle crashes associated with normal 4 way intersections. Fewer injuries/fatalities.

The FL DOT had taxpayers pay for one at I-75 and University in Sarasota. I believe that they opened it too early....at first it was a sea of orange barrels......there were over 20 accidents in the forst 24 hours of operation! It was shut down for a few days to finish striping (VERY important) and to reduce the number of barrels.
There seem to be fewer accidents (at least reported) now....
This is Florida....home of the worst drivers in the USA (you could look it up).

Ride Safe