# Diverging diamond interchanges **URL:** \ **Category:** Safety\ **Created:** [May 29, 2024, 5:47am UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010 "2024-05-29T05:47:38Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![RandomTroll](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/randomtroll/32/12184_2.png) [@RandomTroll](https://community.cartalk.com/u/RandomTroll)\ **Post date:** [May 29, 2024, 5:47am UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/1 "2024-05-29T05:47:38Z")
> **[The 'diverging diamond interchange' may come soon to a busy intersection near...](https://www.npr.org/2024/05/28/nx-s1-4876879/the-diverging-diamond-interchange-may-come-soon-to-a-busy-intersection-near-you)** > > An unconventional design known as the diverging diamond interchange has proven to be safer and more efficient than conventional left turn lanes. Road planners across the country are switching sides. ---
**Author:** ![It\_s-Me](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/it_s-me/32/12660_2.png) [@It\_s-Me](https://community.cartalk.com/u/It_s-Me)\ **Post date:** [May 29, 2024, 6:35am UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/2 "2024-05-29T06:35:58Z")
I can see where that would take some getting used to > **[Diverging diamond interchange](https://en.wikipedia.org/wiki/Diverging_diamond_interchange)** > > A diverging diamond interchange (DDI), also called a double crossover diamond interchange (DCD), is a subset of diamond interchange in which the opposing directions of travel on the non-freeway road cross each other on either side of the interchange so that traffic crossing the freeway on the overpass or underpass is operating on the opposite driving side from that which is customary for the jurisdiction. The crossovers may employ one-side overpasses or be at-grade and controlled by traf The di... ---
**Author:** ![bloody\_knuckles](https://avatars.discourse-cdn.com/v4/letter/b/ee7513/32.png) [@bloody\_knuckles](https://community.cartalk.com/u/bloody_knuckles)\ **Post date:** [May 29, 2024, 7:49am UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/3 "2024-05-29T07:49:22Z")
Everything new takes some getting used to. The question is whether it is safer and more efficient. The answer is yes on both counts. I have experienced it and it works great. If driving through a DDI confuses you at all after your first time through it then my guess is you should not be driving. ---
**Author:** ![PvtPublic](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/pvtpublic/32/13089_2.png) [@PvtPublic](https://community.cartalk.com/u/PvtPublic)\ **Post date:** [May 29, 2024, 8:20am UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/4 "2024-05-29T08:20:51Z")
We have several here in VA. It took a little getting used to, but easy to navigate. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [May 29, 2024, 11:41am UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/5 "2024-05-29T11:41:03Z")
We have many planned and one currently under construction as well as one or 2 up I 75 from me. I have encountered them… the first time was confusing, the 2nd time was OK. Our nearest one will be completed just before the start of the tourist season. I hope there is a traffic camera accessible from the internet… The car-nage will be hilarious. ---
**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\ **Post date:** [May 29, 2024, 12:13pm UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/6 "2024-05-29T12:13:09Z")
Yep, they work fine. I use one that connects to I-95. At rush hour intersection will have delays, but not as bad as intersections with left turn lanes. IMO, the cloverleaf is still better, no traffic lights required, but they do require more land. ![IMG_2443](https://global.discourse-cdn.com/cartalk/original/3X/2/4/24c788a63597309f1527ed3e11658922c4bc6305.png) ---
**Author:** ![davesmopar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/davesmopar/32/41750_2.png) [@davesmopar](https://community.cartalk.com/u/davesmopar)\ **Post date:** [May 29, 2024, 5:01pm UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/7 "2024-05-29T17:01:15Z")
> [@Purebred](#): > > IMO, the cloverleaf is still better, no traffic lights required, but they do require more land. I agree, never had an issue with a cloverleaf and they are very easy to navigate and safe… I have never even heard of a DDI, but after watching a video of it, I understand it, but I am sure if I had not seen the video and I ran across one, it would be a WTF moment, as well as other drivers would be… ---
**Author:** ![PintoKid](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/pintokid/32/45996_2.png) [@PintoKid](https://community.cartalk.com/u/PintoKid)\ **Post date:** [May 29, 2024, 7:23pm UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/8 "2024-05-29T19:23:44Z")
In NC I navigated one near Asheville, and they are building one outside the Raleigh-Durham airport. It is just a bit strange. I do agree the cloverleaf is better, but yes they need much more space. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [May 29, 2024, 7:36pm UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/9 "2024-05-29T19:36:23Z")
I wonder when the last clover leaf was built. Bet it’s been years. Those tight curls and resulting short merge lanes are a problem. Now all the new ones have long ramps in all directions. Here’s one I pass many days: ![image](https://global.discourse-cdn.com/cartalk/original/3X/0/2/028e77a1114157b630e9d2cfd8ffcba86e150ada.jpeg) ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [May 29, 2024, 7:37pm UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/10 "2024-05-29T19:37:36Z")
The cloverleaf is easy to understand, for sure. My civil engineer father really liked them but as time went on, he agreed it was past its time. Why? Traffic volume. The uphill 270 degree turn slows the traffic at the same time as they are trying to merge into full speed traffic flow which is sharing the very same lane with people slowing to enter a downhill 270 degree turn. That chaos causes tie-ups and accidents right in the middle of an overpass. That’s what diverging diamonds were designed to fix. ---
**Author:** ![lion9car](https://avatars.discourse-cdn.com/v4/letter/l/59ef9b/32.png) [@lion9car](https://community.cartalk.com/u/lion9car)\ **Post date:** [May 30, 2024, 3:15am UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/11 "2024-05-30T03:15:55Z")
> [@Purebred](#): > > IMO, the cloverleaf is still better, no traffic lights required, but they do require more land. A cloverleaf has a weave area. A DDI doesn’t. I wouldn’t say the cloverleaf is better. ---
**Author:** ![Barkydog](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/barkydog/32/2470_2.png) [@Barkydog](https://community.cartalk.com/u/Barkydog)\ **Post date:** [May 30, 2024, 4:29am UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/12 "2024-05-30T04:29:48Z")
Looked at the wiki page, I could deal with that! [https://upload.wikimedia.org/wikipedia/commons/1/10/Diverging\_diamond\_redone.svg](https://upload.wikimedia.org/wikipedia/commons/1/10/Diverging_diamond_redone.svg) ---
**Author:** ![wolyrobb](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/wolyrobb/32/45497_2.png) [@wolyrobb](https://community.cartalk.com/u/wolyrobb)\ **Post date:** [May 30, 2024, 6:02am UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/13 "2024-05-30T06:02:49Z")
There’s been one here for a couple years, works very well once you get used to it. Felt wierd to turn left at the off ramp directly onto the left side of the overpass. Redo of an existing overpass to improve traffic flow going to and from I-5, ---
**Author:** ![Cavell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cavell/32/43396_2.png) [@Cavell](https://community.cartalk.com/u/Cavell)\ **Post date:** [May 30, 2024, 4:13pm UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/14 "2024-05-30T16:13:05Z")
![image](https://global.discourse-cdn.com/cartalk/original/3X/1/8/181aed6a3510a608da053619f1b22d582e39ba52.jpeg) Or, you dont want to merge nicely? You WILL stop and merge now. Highway dept will control how you drive. There is NO merging now. ---
**Author:** ![davesmopar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/davesmopar/32/41750_2.png) [@davesmopar](https://community.cartalk.com/u/davesmopar)\ **Post date:** [May 30, 2024, 4:42pm UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/15 "2024-05-30T16:42:35Z")
Most all of our merge on and off ramps are plenty long, with plenty of merge room… ---
**Author:** ![PvtPublic](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/pvtpublic/32/13089_2.png) [@PvtPublic](https://community.cartalk.com/u/PvtPublic)\ **Post date:** [May 30, 2024, 7:58pm UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/16 "2024-05-30T19:58:15Z")
> [@davesmopar](#): > > Most all of our merge on and off ramps are plenty long, with plenty of merge room… Around the Greenwich area of I95 in CT you are lucky if you get 10 Feet of merge area. I’m glad my car has more than adequate acceleration. 😃 ---
**Author:** ![cigroller](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@cigroller](https://community.cartalk.com/u/cigroller)\ **Post date:** [May 30, 2024, 9:11pm UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/17 "2024-05-30T21:11:59Z")
> [@davesmopar](#): > > Most all of our merge on and off ramps are plenty long, with plenty of merge room… Same here. But too bad so many people don’t know how to use them. There are some short ones in my area, but most are plenty long. The ones I use most frequently (on/off side of same entry/exit) are nice and long. Ideal, really. Yet I frequently find myself behind “that person” who thinks you “cautiously” (!?) go down the entry ramp at like 40-45 only to speed up once entering 70mph traffic!? WTH are you thinking? Then the are the (probably same) ones who think they need to slow down BEFORE hitting the ramp. WTH? I don’t get it. It defies even common sense. As for the diverging diamonds, I have two near me. One has been a god-send in terms of smooth/much faster traffic flow at a busy rural main highway / interstate interchange. The other is also fine, but the lights aren’t synced correctly so it doesn’t work as well as it could. I’ve reported that to DOT, but the DOT people around me are apparently dense. ---
**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\ **Post date:** [May 31, 2024, 1:11pm UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/18 "2024-05-31T13:11:35Z")
Yep, still get behind people that want to merge into 75MPH traffic at 35MPH, no matter how long the merge lane is. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [May 31, 2024, 3:00pm UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/19 "2024-05-31T15:00:12Z")
More on DDI: [Intersection baffling drivers with cars traveling on ‘wrong side of the road’ explained (msn.com)](https://www.msn.com/en-us/news/us/intersection-baffling-drivers-with-cars-traveling-on-wrong-side-of-the-road-explained/ar-BB1nhlF6?ocid=entnewsntp&pc=U531&cvid=d547c0cebde741e6b1d7b33b414f6a7f&ei=10) ---
**Author:** ![Cavell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cavell/32/43396_2.png) [@Cavell](https://community.cartalk.com/u/Cavell)\ **Post date:** [May 31, 2024, 9:12pm UTC](https://community.cartalk.com/t/diverging-diamond-interchanges/195010/20 "2024-05-31T21:12:00Z")
![image](https://global.discourse-cdn.com/cartalk/original/3X/d/2/d2cb0ac5c74c9bd4790c9828627f7281c73d55e1.jpeg) These are odd also. You are on left side and oncoming traffic is on your right. If you exit highway by mistake you cannot drive thru intersection and get back on the highway. [Next page](https://community.cartalk.com/t/diverging-diamond-interchanges/195010.md?page=2)