I like the diverging diamond way better than circles. But I'd build a X-shaped walkway above the diamond with ramps at all 4 corners for walkists and cyclers.
@@fredashay As much as this has more conflict points for pedestrianized traffic, which I agree is definitely is a downside, these aren't being installed in places with extremely high pedestrian traffic volume anyway... Yes, you could argue that this further hinders pedestrians from crossing, but I think the highway itself does that more than anything else, so I don't think the DDI interchange actually makes a big difference.
They have built several of these in Atlanta. I drive through one all the time. It is pretty hard to not understand how to navigate one. If you can't figure a DD interchange, you probably shouldn't be driving. They are very well signed and marked.
As a professional truck driver it makes getting around interchanges safer by creating more space for 18-wheelers and cars to move around each other. The negative is as you said if I need to go across or make a mistake and get off on the wrong interchange getting turned around can be an utter nightmare and when you are used to The Interchange being a certain way I find myself in the wrong lane because I'm used to it being a Cloverleaf that's the ones that they usually are converting to this system that you're describing. Thank you for your videos they are absolutely fascinating to me been doing this for 20 years up and down the interstate and thanks your videos are educational and better understand and safely navigate the interstate system. As a trainer it's a big help keep doing what you doing man appreciate it
That is another downside. It might be a good idea where there is an existing diamond interchange and population growth necessitates increasing road capacity. But if we already have a cloverleaf, then a diverging diamond is not as big an improvement, for a number of reasons, including the one you stated. There should also be a fairly straightforward means of u-turning on the roads leading to and from a diverging diamond that allows a lost driver to get back on the expressway.
The interchange that is proving to be unpopular in densely populated areas is the cloverleaf interchange. Cloverleafs here in Maryland seem to be all being reconstructed into hybrid partial cloverleafs or, if it’s not an interchange featuring two interstates, a typical diamond. I personally like the single point urban interchange (SPUI) because it’s more free-flowing even with a single traffic light.
TDOT recently built a SPUI (Exit 82) in jackson tn, my birthplace and it heavily depends. it replaced a outdated and heavily backed up cloverleaf service interchange. the lights weren't synchronized and a lot of traffic from highland avenue often don't turn onto the interstate, they often turn onto Vann Drive to get to major shopping at the columns and the columns II and with the columns III being developed now, its only a matter of time before TDOT would need to fix the biggest mistake they made. they assumed drivers would take the interstate to vann drive (Exits 80B, and 79) but that isn't the case, especially since theres no ramp to vann drive if you take exit 80B and you'd have to drive a extra mile to the very next exit (Exit 79) theres a indirect way to Vann Drive from the same exit, exit 80B, which takes you to stonebridge blvd. but that road is already very congested during rush hour and probably will not be able to keep up with local demands for very long. if anything, TDOT and the City of Jackson need to figure out how to best deal with that area, or its gonna be like a blood clot on a 85 year old man, and back up the surrounding roads, like US 45 bypass, I-40 WB, stonebridge blvd, union university Dr, Pleasant Plains Extension, channing way, and Emporium drive. it might even back up country club ln, as well but idk. either way, hope TDOT realizes their mistake there, or its gonna get bad within the first 20 years after 2024 when they finally finish the I-40 widening project.
@@MileageMikeTravels Oh boy.. wait till you drive on the long island (NY) parkways.. filled with outdated cloverleafs that are tight and dangerous. Oh, and absolutely no time to merge on with the tight parkway.
I used the one at Ashford-Dunwoody and I-285 often and did feel like it improved traffic flow. With it only being 2 signal phases, they feel pretty long and enough for you to clear the entire thing most of the time.
They converted the I-88/IL-59 interchange to a diverging diamond type recently. It was weird at first, but you just follow the signs and all is good. Those two lights come up unexpectedly so it takes a little getting used to. You wonder, at first why they complicated the simple interchange we had, this video explains it, so thank you for that!
The nice thing about diverging diamonds here in NC (so far as the posting of this comment) they are utilized well and it is very straight forward on what to do. if someone gets confused all they would have to do is follow the flow of traffic since the lanes are well marked. edit: That and single point interchanges, it saves the need for two intersections into one. I like both and we should implement them more often. Of course make them easy to transverse as a biker or pedestrian if we could.
I went slightly out of my way to sample one at El Paso. It worked very smoothly, and I approve. The way it was marked and signaled, it was almost a non-event. A solid barrier between the opposing lanes in the reverse-running segment is important to prevent confusion.
The DDI on I-75 in Florida at University Parkway (Exit 213) did somewhat help with the backups getting to the interstate, especially with expanding the amount of lanes available, though with several shopping centers next to it, traffic can vary as it comes and goes.
I live nearby this interchange and I agree with you. A great design that replaced the standard diamond, but now with the massive UTC shopping district right next to it, University Pkwy backs up for almost a mile approaching the interchange during the afternoon. There is too much traffic on the Cattlemen/Cooper Creek light now which holds up traffic. A very efficient design, but everything around it reduces its efficiency a lot.
@John Williamson Whether a design is ugly or not is a personal preference so if is ugly to you that is ok. Now if you are referring to how organized the interchange is, it is not more unorganized than a standard diamond interchange. It takes up just about the same right of way and nothing about the DDI’s layout is unnecessary to achieve its goal. Concerning your opinion that no one in the United States should not drive on the left side of the road, why is that such a problem according to you? First off, the portion of left-hand side driving in a DDI is very short. It takes seconds to enter and leave that portion of road. Second of all, that section of road is heavily divided from the opposing lanes. If the driver isn’t distracted, they wouldn’t even notice the other side of the road. It is like driving on a one way street. Finally, it is not confusing or hard to use. It is unusual to most people as they haven’t been used in the US until recently and is a foreign design, originating from France. However, all DDIs that I have used are heavily marked on the road and are signed very well, more so than most other interchanges. The DDI forces you to face directly at the lanes you will enter at each traffic signal. It is almost impossible to enter the opposite lanes without activity trying. By the way, France drives on the right side of the road, just like the US. The DDI was made by them and still exists. Should France stop using them too just because according to you no one in the US should not have to drive on the opposite side of the road? Like many others have said in the comments, if you can’t ‘navigate’ a DDI, you shouldn’t even be driving in the first place.
@John Williamson I don’t think you understand that a standard diamond used in a largely developed area doesn’t work very well at all. In a rural setting where there isn’t high traffic on the highway and the road, yes a standard diamond works and it is very cheap to construct and maintain. If you have a 3+ lane major interstate and a 3+ lane arterial intersecting each other in a large commercial area that leads to a moderately busy commercial airport, many shopping districts, and runs in the middle of a 400,000+ populated area, a standard diamond fails to keep the traffic flowing smoothly enough. Why do you think standard diamonds in areas like that are being replaced? They ran traffic studies for a few years here on Exit 213 which was a standard diamond before replacing it with a DDI. It wasn’t enough to handle the growing development anymore. Sure, it worked fine when it was first constructed half of the surrounding area was cow fields and unused land with a few spots of commercial areas. Now all the empty land is filled with commercial districts. They replaced it with a DDI back in 2015-2016 and in 2022, it is still running smoother than ever. The DDI works in areas like this, the standard diamond doesn’t. Good luck trying to defend the standard diamond. It is not a flawed or broken design, but it doesn’t work everywhere. It is meant for low traffic volumes only. As long as the US keeps growing, their presence on the interstate system will dwindle. Also, if you think a DDI is confusing, have you ever been through a rotary/traffic circle? I see people stopping left and right inside the circle to let those who aren’t inside of it go ahead all the time because they don’t know how to use it. I don’t see people acting like that in a DDI. Like I said before, it is extremely well marked and divided from the opposing lanes. It is hard to fail to understand how to use it. If is a proven safe design and I have never seen an accident inside a DDI. I have seen many accidents in and near a rotary/traffic circle.
@John Williamson I must say you are extremely ignorant or just a troll. You ask for everyone’s credentials while you can’t even provide any reasoning as to why you believe your opinion. Believe want you want but the facts and research are there all over the internet and in the real world for you to see but you don’t want to open your eyes. You want to interject your baseless opinions everywhere and call people fools for believing a lie that doesn’t exist. When someone provides their reasoning, you just continue to restate your opinion without any reason regardless of what they say. I’m a fool for wasting my time. There are too many pig-headed people like you out there, especially in the US. There’s no wonder why we are in such turmoil. I’m done here, I’ve wasted enough time arguing with a brick wall.
A DDI interchange was constructed in the renovation of Interstate 285 and Georgia Highway 400 in the Atlanta Suburb of Sandy Springs. Thanks for the video. You have a great voice, Mileage Mike. God Bless and Keep Your I like your narration Videos where you talk doing them. You have a good voiew to use on them.
here in Miami SR836 and SR9/27th Ave was recently converted into a DDI. When these are proposed, there’s always comments about confused drivers. There has never been an incident of a wrong way driver at this interchange because as you drive through it, you cannot sense that you’re on the opposite side of the road. It’s only at an ariel view can you see the lane switch
They converted an interchange along I-26 just south of Asheville, NC into one of these several years ago and it’s worked very well. The interstate is currently being widened and they’re working on converting another interchange into a DDI
Great video as usual. Just wondering if you could make a video on round-abouts or “rotaries”. I heard they reduce accidents and have better traffic flow at intersections as well.
@@MileageMikeTravels Yes, a video about Roundabouts ( both positives and negatives) would be an interesting topic to cover by someone like you who is an expert.
The DD you mentioned at I-85 & Jimmy Carter in Atlanta is TIGHT! All the concrete walls have semi trailer tire scrub marks from big trucks trying to squeeze through! We don’t have too many in Florida or head-on collisions will go way up!!😮
WA state recently completed its first DDI in Lacey at Exit 111 on I-5 (Marvin Road exit). There's a bit of resistance from those who don't like the new way of doing things, but people will eventually get used to it. The state is starting to build its second one at the junction of I-90 and SR 18 near North Bend.
While there are more crossings for pedestrians, the overall design is safer. They typical have a barrier separation in the center and several short crossings.
4:27 Actually you are not guaranteed to stop at somepoint in the interchange unless you’re turning left from the freeway onto the arterial road. If you’re on the arterial going straight through you should get both greens if already green when entering. As for left turning onto the freeway, you only need to pass through one light. For all right turns it’s free flowing.
Here in Alabama. The first DDI was built in Daphne, Alabama. I live about 20 minutes north of Daphne. After it was built (To Me) I really didn't see any change. It's like more, more, and more people are moving to the area and more, more, and more traffic is backed up even on the DDI. I have seen accidents were people are trying to beat the light. It can be crazy at times. But it has It's Pro's and Con's.
I drove the SR 13 / I-44 a few years after it opened. When doing a Right Turn on Red, you must be careful where you look since the traffic crosses from the left to the right. DDIs work very well when there is a lot of traffic entering/exit the freeway, but not so go for thru traffic. The SPUI is the better choice for high-traffic interchanges without Fly Over ramps. As usual, the DOTs gets a 'new idea', and they go overboard with it. For low volume interchanges, I seem to like the dumbbell over the standard diamond exchange.
I drove one that was in Tulsa, Oklahoma. They had just finished building it recently, and I didn’t know they had plans to put the interchange at Memorial and OK169 until I ended up driving through that to get home. I was so confused by it. It didn’t effect me getting home, and I think that’s pretty good even though I think they’re still working on some small final touches in order to make sure everyone has a way to get through the interchange. But overall, it did great.
Yes Virginia... loves them! I-64 and US 15... the literal "Zion Crossroads." Think it's funny every time I drive pass that. Then I-66 and US 15 in Haymarket. They're building a new one in Charlottesville right now. I-64 exit 124 crossing US 250. The first one I've seen where the crossroad is under the Interstate rather than over. Say it'll be done by end of year. Be safe out there you all!
The I-196/US 131 interchange in Grand Rapids, Michigan is much like a diverging diamond except that the opposing lanes of US 131 are separated with bridges. This is a two-freeway crossing, and it works well.
The left exits are a big problem with that interchange, though. Slower traffic has to merge into the passing lane to take 131N to 196W, or the reverse. Also, this is less than a mile from the dramatic curve by The Intersection, hence why there are so many accidents here relative to other interchanges in Michigan.
i drove through a DDI and loved it tbh. paducah, ky exit 4. KTC built a DDI for exit 4 on I-24 in paducah, ky, felt great to drive on, especially when i had that nissan versa as its literally a breeze to get onto the interstate. and i don't normally have problems missing the exit or taking the wrong exit, but it does make it safer for people who missed a exit and have to take a exit with a DDI in it to turn around as you don't risk a serious accident making 2 left turns to turn around, you still make them but you don't cross traffic to get to it, which is a plus tbh. yes traffic that took the wrong exit and need a exit or two down, they would be forced to turn around at a local shopping center or someplace nearby, which can add to local traffic. but maybe a roundabout a intersection or two down from each DDI might work?
One is still being discussed for I-89 and US-2 in Colchester, VT (exit 16 just past the Winooski town line) but it's been in the planning phase for years.
The state of Michigan is implementing these all over the place. There are several in the Detroit area now. Big Beaver and I75, University Dr & I75, and a new one currently being constructed at 12 Mile and I75.
There is 4 on I-75 in Oakland Co, MI. 2 of them are fully built and the other 2 are under construction. They are part of the reconstruction of I-75 through Oakland Co. that is upgrading from the original design. The first DDI was built in 2015 and is Exit 79 University Dr. The other 3 are exit 69 Big Beaver Rd.(16 Mile Rd.) exit 65 14 Mile Rd. and exit 63 12 Mile Rd. I have driven straight through on the Big Beaver Rd. which was weird at first but have not used the ramps yet.
I glance over 12 Mile Road all of the time, which is closed east of Stephenson Highway. It’s progressing as they have the traffic signals up on that side.
I like these interchanges, there is one I sometimes frequent at I-35 and 95th Street in Overland Park, KS. I just knew that one of the "downsides" to these interchanges is stupid drivers. Kind of like how people are anti-roundabouts because they don't know how to drive. However, that shouldn't be a deterrent to building more efficient and safe roads.
There is one at the US-21 and I-40 intersection in Statesville, NC. The intersection is nice but the signaling for the interchange is poorly done, the ground mounted signal isn't visible at all and the overhead signals are barely visible, even less so during the day.
I used the I44 / SR 13 DDI in Springfield a couple of years after it opened. If you have a lot of traffic entering and exiting the Freeway, it works very well. Unfortunately, I expect State DOTs will overuse this design. I have driven the new I 69 between Martinsville IN and SR 144. Both SR 44 and Henderson Ford road are 'dumbbell' exchanges. I think these are much safer than the original diamond exchange. It will be interesting how the SR 44 / I 69 2-lane 'dumbbell' interchange will hold up as traffic increases. One advantage of dumbbell exchanges -- it is very easy to reverse travel. In the event you got off at the wrong interchange, it is very easy to loop around and get back on.
I live in Charlotte, so I see these pretty often. I did go through one in Colorado Springs last year that kind of surprised me as I thought it was mostly an NC and GA thing.
There's one at College Dr. and I-25 in Cheyenne, WY. First time I used it, didn't care for it and it was a bit confusing, especially getting off from SB I-25 and not recognizing traffic coming from the right at the yield sign to go left. Now however, I like the design. Better than left turn lanes and arrows.
Indiana has built a handful as far as I'm aware. The first one was at Worthsville road and I-65. There is another on the northeast side of Indianapolis, and two more are near completion on I-65 near Whitestone Indiana. These two, (one being a conversion, and the other an entirely new interchange) are only a mile or so apart from each other. Edit: After recounting, there are four completed DDI's in Indiana, and two nearly completed DDI's.
Yes, and at one point, there was supposed to be a DDI at the I-265 with SR 62 in Jeffersonville. INDOT dropped that idea and replaced it with a really badly-designed roundabout interchange.
IIRC, Illinois' first DDI was I-88 at Route 59. I remember extreme confusion when it first opened, but it works so much better now - that Intersection used to constantly back up well onto the freeway, and it doesn't nearly as often now.
FDOT announced plans to convert I-10 Exits 5 and 7 near Pensacola to DDIs. Locals are freaking out about it, just as they did when FDOT converted a major intersection to a roundabout/flyover last year.
The Diverging Diamond Interchange is at I-95's Exit 22 in Lumberton, N.C. Another interchange is being constructed at I-20's Exit 190 in Grovetown, Ga.
There is one of these at the intersection of US 15 and I 64 in Virginia. It is absolutely amazing. A shame they can only stick them in rural areas instead of the Urban Areas where they are desperately needed.
I don’t understand why you say they can only put these in “rural” areas. The one at Zion Crossroads you mention (I-64 at US 15) is likely one of the most rural locations with one that I have heard of. It seems most of them are being put in very busy, suburban areas where there is clearly a significant need for them…
They have a DDI at 222/322 interchange in Ephrata, Lancaster County, PA. It messed me up at first, but once I did a little research, it made sense. I don't actually live in the area, so have no idea if it's helped congestion there.
I have used almost all the diverging diamond interchanges in Georgia and they do have many advantages however many people get confused as to which lane turns left onto the highway.
I've seen several DDI's here in North Carolina, including one at Gate City Boulevard and I-73 in Guilford County and one at Research Parkway and US 52 in Winston-Salem.
In my opinion, I think that they are not that hard to navigate. The signs are usually great since most are built in recent times. Another DDI is coming to GA at Exit 4 on I-185 (Buena Vista Rd). I watched the one at Exit 2 on I-285 get built. I like DDI's and I think they are better than traffic circles/roundabouts. I think roundabouts should only be used in residential areas because they're not the best for truckers. You should also do a video about roundabouts, and maybe all types of interchanges and intersections.
I'm mad I immediately identified the Charlotte area interchanges. But go through quite a few of them. Nice shot of the Ben Franklin Bridge at the end too.
Here in the Kansas City, Missouri area, in Lee's Summit, there is a dirvegabout. It is a diverging diamond with a roundabout on one end. I did not think that it would work, but it does, and flows nicely.
i live near the Raleigh Durham NC area and I've seen on the news where the DDI was being built on Airport Blvd by the RDU airport and on the Western Blvd / Blue Ridge Rd intersection in Raleigh. Being a former Uber/Lyft driver I was hoping to experience a DDI drive thru on one of those. Just last week though, I unexpectedly went thru a DDi in the Mebane Burlington area, making a left onto the interstate. It was a short wait at one traffic light. After that , it was a free flowing exit with no head-on interactions with another car, just as shown in this video.
I've been through one at Gold Hill Road and I-77 one time when I was riding in a car with my brother and my dad. My dad felt like he was on the wrong side of the street.
In Michigan, MDOT has built a ton of them recently: I-96 at Cascade Rd in Grand Rapids I-75 at University Dr in Auburn Hills I-75 at Big Beaver Rd in Troy I-75 at 14 Mile Rd in Madison Heights I-75 at 12 Mile Rd in Madison Heights I-94 at US 127/M-50 in Jackson I suspect we will see more in the future at other known trouble spots on Michigan's freeways. I'm hoping that there are plans in the work to convert the interchange of I-75/US 23 at M-54/M-83 in Birch Run to one of these. Would really help.
I live near Joplin, MO. There's one at I-44, Exit 8, Range Line Road. It seems to always do a good job moving traffic through. People walk on a sidewalk in the middle protected by barriers and it actually seems decent for them. Not many people seem to walk near the interchange anyways. I have witnessed a few people go the wrong way when going straight through, including a couple at me but thankfully in the other lane. I have seen many people make very odd and dangerous U-turns on the Range Line intersection. There's really no good reason for this!! You could get hit by traffic turning off the freeway that is not expecting you to suddenly illegally U-turn back in their path.
Virginia has two DDI's on US-15; at I-64 and at I-66. VDOT is currently rebuilding US-250 into a DDI at I-64 near Charlottesville. Why didn't someone come up with this idea sooner?
@@MileageMikeTravels I think they are ugly, in that they are usually lined with commercial sprawl that seems to go on forever. I would rather see forest along the highway, which you see in most other, especially Eastern, states.
I support DDIs, but they are not appropriate everywhere. A DDI is supposed to be at the I-66 Nutley St interchange but decided to do an unsignalized double roundabout interchange with loop ramps entering the I-66 regular lanes instead. This change made the most sense. I even heard of a proposal to change the cloverleaf interchange at the Old Ox Rd/Route 28 interchange to a DDI based on what I heard from VDOT about improving the Route 28 corridor between Frying Pan Rd and Sterling Blvd in order to reduce traffic weaving although auxiliary lanes are provided there.
Diverging Diamonds seem very confusing. They are planning for one in my area at FM 60 / University Drive and Hwy 6 / Earl Rudder Fwy in College Station, Texas.
Yes, and at one point, there was supposed to be a DDI at the I-265 with SR 62 in Jeffersonville. INDOT dropped that idea and replaced it with a really badly-designed roundabout interchange.
I live around the New York City Metro Area So We Dont See DDI’s Around Here When I drove to Atlanta for the first time My First was The Pleasant Hill Rd that was shown at 0:14 I was so confused. But the more I went on it i started to like it.
Diverging Diamonds are okay I guess. The biggest problem is that most DOTs aren't designing them correctly. A majority of DDIs use no-turn-on-reds at most, if not _all_ , merging movements, which significantly impairs traffic flow. VDOT installed a DDI at the interchange of I-66 and US-15 in Haymarket, and that intersection has become a total traffic flow trainwreck since. I avoid that intersection at all costs.
Returning from South Carolina to Pennsylvania, I used US 15 as an alt to the ridiculous traffic on 95. Went through this exact DDI and didn't experience any problems. Ofc just a one time experience but it was on Labor Day where traffic would've been at a peak.
I use the Haymarket DDI several times a week. I've never had a problem traversing it, nor heard anyone refer to it as a trainwreck. It's much better than what was there before, especially for traffic from southbound Rt 15 heading east on I-66.
@@gr8deadfan75 It's _especially_ bad for motorists heading north on US-15. The interchange itself should not have been a DDI given that both I-66 and US-15 are major through routes, so both need to have some degree of free flow, which DDIs do not provide.
@@Mapmaker1559 I agree the no turn on red is unwarranted at that intersection however I’d argue the the US-15/John Marshall Hwy intersection right next to it is far worse. I end up sitting at that one for far longer no matter which way I approach. It’s cycle and timing with the other close lights is all sorts of messed up
The Austin district of TxDOT has been retrofitting existing interchanges with them for several years now. They've also built a new one from scratch at Mopac and Slaughter Ln in south Austin.
My solution for the confusion from driving temporarily on the left side of the road: block the view of the opposing traffic on the other side with a barrier.
The interchange at I-66 and US-15 in Haymarket does not flow better since becoming a DDI. Especially for traffic heading north on US-15. The interchange has become a nightmare for traffic flow. I've gone through it several times, I can personally attest that it is _not_ good. Maybe DDIs work well at other intersections, but that interchange in particular should _not_ be a DDI, one of VDOT's worst mistakes ever.
@@willn703 Exactly. The extremely poor signal timing is the biggest reason traffic flow through the interchange is so bad. Even if the interchange doesn't congest terribly, the signal light delays are awful, and that factors into a measure of traffic flow.
DD are just another example of self-indulgent incompetence and the lack of any real innovation in the road bureaucracy. Express way crossings should have...wait for it...0 (zero) crossings. The solution is shockingly simple...anyone??????? And no, the answer is not a round-about, though that would be way better then a DD.
Roundabouts lose efficiency at 25,000 vehicles per day (45,000 for dual lanes). Not to mention the added cost for right of way that would still be inefficient for the large volumes this interchange would handle. Roundabout interchanges are best for rural areas.
Thanks for watching.
See more Commentary Style Videos Here: th-cam.com/play/PLnS3Ajs4YX_y7SG4bKBuqHcBmfOaOoIn4.html
I like the diverging diamond way better than circles.
But I'd build a X-shaped walkway above the diamond with ramps at all 4 corners for walkists and cyclers.
@@fredashay As much as this has more conflict points for pedestrianized traffic, which I agree is definitely is a downside, these aren't being installed in places with extremely high pedestrian traffic volume anyway... Yes, you could argue that this further hinders pedestrians from crossing, but I think the highway itself does that more than anything else, so I don't think the DDI interchange actually makes a big difference.
They have built several of these in Atlanta. I drive through one all the time. It is pretty hard to not understand how to navigate one. If you can't figure a DD interchange, you probably shouldn't be driving. They are very well signed and marked.
As a professional truck driver it makes getting around interchanges safer by creating more space for 18-wheelers and cars to move around each other. The negative is as you said if I need to go across or make a mistake and get off on the wrong interchange getting turned around can be an utter nightmare and when you are used to The Interchange being a certain way I find myself in the wrong lane because I'm used to it being a Cloverleaf that's the ones that they usually are converting to this system that you're describing. Thank you for your videos they are absolutely fascinating to me been doing this for 20 years up and down the interstate and thanks your videos are educational and better understand and safely navigate the interstate system. As a trainer it's a big help keep doing what you doing man appreciate it
That is another downside. It might be a good idea where there is an existing diamond interchange and population growth necessitates increasing road capacity. But if we already have a cloverleaf, then a diverging diamond is not as big an improvement, for a number of reasons, including the one you stated. There should also be a fairly straightforward means of u-turning on the roads leading to and from a diverging diamond that allows a lost driver to get back on the expressway.
The interchange that is proving to be unpopular in densely populated areas is the cloverleaf interchange. Cloverleafs here in Maryland seem to be all being reconstructed into hybrid partial cloverleafs or, if it’s not an interchange featuring two interstates, a typical diamond. I personally like the single point urban interchange (SPUI) because it’s more free-flowing even with a single traffic light.
True. Been traveling through New Jersey lately and seeing lots of dated, dangerous cloverleafs with very short merge areas.
TDOT recently built a SPUI (Exit 82) in jackson tn, my birthplace and it heavily depends. it replaced a outdated and heavily backed up cloverleaf service interchange. the lights weren't synchronized and a lot of traffic from highland avenue often don't turn onto the interstate, they often turn onto Vann Drive to get to major shopping at the columns and the columns II and with the columns III being developed now, its only a matter of time before TDOT would need to fix the biggest mistake they made.
they assumed drivers would take the interstate to vann drive (Exits 80B, and 79) but that isn't the case, especially since theres no ramp to vann drive if you take exit 80B and you'd have to drive a extra mile to the very next exit (Exit 79)
theres a indirect way to Vann Drive from the same exit, exit 80B, which takes you to stonebridge blvd.
but that road is already very congested during rush hour and probably will not be able to keep up with local demands for very long. if anything, TDOT and the City of Jackson need to figure out how to best deal with that area, or its gonna be like a blood clot on a 85 year old man, and back up the surrounding roads, like US 45 bypass, I-40 WB, stonebridge blvd, union university Dr, Pleasant Plains Extension, channing way, and Emporium drive. it might even back up country club ln, as well but idk.
either way, hope TDOT realizes their mistake there, or its gonna get bad within the first 20 years after 2024 when they finally finish the I-40 widening project.
@@MileageMikeTravels Oh boy.. wait till you drive on the long island (NY) parkways.. filled with outdated cloverleafs that are tight and dangerous. Oh, and absolutely no time to merge on with the tight parkway.
I used the one at Ashford-Dunwoody and I-285 often and did feel like it improved traffic flow. With it only being 2 signal phases, they feel pretty long and enough for you to clear the entire thing most of the time.
They converted the I-88/IL-59 interchange to a diverging diamond type recently. It was weird at first, but you just follow the signs and all is good. Those two lights come up unexpectedly so it takes a little getting used to. You wonder, at first why they complicated the simple interchange we had, this video explains it, so thank you for that!
They did one at I-55 and Weber Road in Bolingbrook just recently
The nice thing about diverging diamonds here in NC (so far as the posting of this comment) they are utilized well and it is very straight forward on what to do. if someone gets confused all they would have to do is follow the flow of traffic since the lanes are well marked.
edit: That and single point interchanges, it saves the need for two intersections into one. I like both and we should implement them more often. Of course make them easy to transverse as a biker or pedestrian if we could.
@John Williamson I don't mind it either way but I can understand an average pedestrian or average driver uncomfortable with such designs
I went slightly out of my way to sample one at El Paso. It worked very smoothly, and I approve. The way it was marked and signaled, it was almost a non-event. A solid barrier between the opposing lanes in the reverse-running segment is important to prevent confusion.
The DDI on I-75 in Florida at University Parkway (Exit 213) did somewhat help with the backups getting to the interstate, especially with expanding the amount of lanes available, though with several shopping centers next to it, traffic can vary as it comes and goes.
I live nearby this interchange and I agree with you. A great design that replaced the standard diamond, but now with the massive UTC shopping district right next to it, University Pkwy backs up for almost a mile approaching the interchange during the afternoon. There is too much traffic on the Cattlemen/Cooper Creek light now which holds up traffic. A very efficient design, but everything around it reduces its efficiency a lot.
@John Williamson Would you care to explain your opinion?
@John Williamson Whether a design is ugly or not is a personal preference so if is ugly to you that is ok. Now if you are referring to how organized the interchange is, it is not more unorganized than a standard diamond interchange. It takes up just about the same right of way and nothing about the DDI’s layout is unnecessary to achieve its goal.
Concerning your opinion that no one in the United States should not drive on the left side of the road, why is that such a problem according to you? First off, the portion of left-hand side driving in a DDI is very short. It takes seconds to enter and leave that portion of road. Second of all, that section of road is heavily divided from the opposing lanes. If the driver isn’t distracted, they wouldn’t even notice the other side of the road. It is like driving on a one way street. Finally, it is not confusing or hard to use. It is unusual to most people as they haven’t been used in the US until recently and is a foreign design, originating from France. However, all DDIs that I have used are heavily marked on the road and are signed very well, more so than most other interchanges. The DDI forces you to face directly at the lanes you will enter at each traffic signal. It is almost impossible to enter the opposite lanes without activity trying. By the way, France drives on the right side of the road, just like the US. The DDI was made by them and still exists. Should France stop using them too just because according to you no one in the US should not have to drive on the opposite side of the road?
Like many others have said in the comments, if you can’t ‘navigate’ a DDI, you shouldn’t even be driving in the first place.
@John Williamson I don’t think you understand that a standard diamond used in a largely developed area doesn’t work very well at all. In a rural setting where there isn’t high traffic on the highway and the road, yes a standard diamond works and it is very cheap to construct and maintain. If you have a 3+ lane major interstate and a 3+ lane arterial intersecting each other in a large commercial area that leads to a moderately busy commercial airport, many shopping districts, and runs in the middle of a 400,000+ populated area, a standard diamond fails to keep the traffic flowing smoothly enough. Why do you think standard diamonds in areas like that are being replaced?
They ran traffic studies for a few years here on Exit 213 which was a standard diamond before replacing it with a DDI. It wasn’t enough to handle the growing development anymore. Sure, it worked fine when it was first constructed half of the surrounding area was cow fields and unused land with a few spots of commercial areas. Now all the empty land is filled with commercial districts. They replaced it with a DDI back in 2015-2016 and in 2022, it is still running smoother than ever. The DDI works in areas like this, the standard diamond doesn’t.
Good luck trying to defend the standard diamond. It is not a flawed or broken design, but it doesn’t work everywhere. It is meant for low traffic volumes only. As long as the US keeps growing, their presence on the interstate system will dwindle.
Also, if you think a DDI is confusing, have you ever been through a rotary/traffic circle? I see people stopping left and right inside the circle to let those who aren’t inside of it go ahead all the time because they don’t know how to use it. I don’t see people acting like that in a DDI. Like I said before, it is extremely well marked and divided from the opposing lanes. It is hard to fail to understand how to use it. If is a proven safe design and I have never seen an accident inside a DDI. I have seen many accidents in and near a rotary/traffic circle.
@John Williamson I must say you are extremely ignorant or just a troll. You ask for everyone’s credentials while you can’t even provide any reasoning as to why you believe your opinion. Believe want you want but the facts and research are there all over the internet and in the real world for you to see but you don’t want to open your eyes. You want to interject your baseless opinions everywhere and call people fools for believing a lie that doesn’t exist. When someone provides their reasoning, you just continue to restate your opinion without any reason regardless of what they say. I’m a fool for wasting my time. There are too many pig-headed people like you out there, especially in the US. There’s no wonder why we are in such turmoil.
I’m done here, I’ve wasted enough time arguing with a brick wall.
A DDI interchange was constructed in the renovation of Interstate 285 and Georgia Highway 400 in the Atlanta Suburb of Sandy Springs. Thanks for the video. You have a great voice, Mileage Mike. God Bless and Keep Your I like your narration Videos where you talk doing them. You have a good voiew to use on them.
here in Miami SR836 and SR9/27th Ave was recently converted into a DDI. When these are proposed, there’s always comments about confused drivers. There has never been an incident of a wrong way driver at this interchange because as you drive through it, you cannot sense that you’re on the opposite side of the road. It’s only at an ariel view can you see the lane switch
They converted an interchange along I-26 just south of Asheville, NC into one of these several years ago and it’s worked very well. The interstate is currently being widened and they’re working on converting another interchange into a DDI
Great video as usual. Just wondering if you could make a video on round-abouts or “rotaries”. I heard they reduce accidents and have better traffic flow at intersections as well.
Good idea!
@@MileageMikeTravels Yes, a video about Roundabouts ( both positives and negatives) would be an interesting topic to cover by someone like you who is an expert.
The DD you mentioned at I-85 & Jimmy Carter in Atlanta is TIGHT! All the concrete walls have semi trailer tire scrub marks from big trucks trying to squeeze through! We don’t have too many in Florida or head-on collisions will go way up!!😮
WA state recently completed its first DDI in Lacey at Exit 111 on I-5 (Marvin Road exit). There's a bit of resistance from those who don't like the new way of doing things, but people will eventually get used to it. The state is starting to build its second one at the junction of I-90 and SR 18 near North Bend.
While there are more crossings for pedestrians, the overall design is safer. They typical have a barrier separation in the center and several short crossings.
Yeah, my mom freaked out when we crossed Windy Hill Rd at its DDI at I-75 near Truist Park.
4:27
Actually you are not guaranteed to stop at somepoint in the interchange unless you’re turning left from the freeway onto the arterial road. If you’re on the arterial going straight through you should get both greens if already green when entering. As for left turning onto the freeway, you only need to pass through one light. For all right turns it’s free flowing.
Here in Alabama. The first DDI was built in Daphne, Alabama. I live about 20 minutes north of Daphne. After it was built (To Me) I really didn't see any change. It's like more, more, and more people are moving to the area and more, more, and more traffic is backed up even on the DDI. I have seen accidents were people are trying to beat the light. It can be crazy at times. But it has It's Pro's and Con's.
You guys also have that new bridge about to come over the Mobile River.
@@MileageMikeTravels Yes......It's been long, long, long overdue.
I drove the SR 13 / I-44 a few years after it opened. When doing a Right Turn on Red, you must be careful where you look since the traffic crosses from the left to the right.
DDIs work very well when there is a lot of traffic entering/exit the freeway, but not so go for thru traffic. The SPUI is the better choice for high-traffic interchanges without Fly Over ramps.
As usual, the DOTs gets a 'new idea', and they go overboard with it.
For low volume interchanges, I seem to like the dumbbell over the standard diamond exchange.
The one we have in Hebron, Kentucky, states "no turns on red"
There is a new one at the i75 and and Florida 56 in Wesley Chapel. It seems to be working better now that most of the construction is over.
I drove one that was in Tulsa, Oklahoma. They had just finished building it recently, and I didn’t know they had plans to put the interchange at Memorial and OK169 until I ended up driving through that to get home. I was so confused by it. It didn’t effect me getting home, and I think that’s pretty good even though I think they’re still working on some small final touches in order to make sure everyone has a way to get through the interchange. But overall, it did great.
Discovered one on I-95, intersection with Viera Blvd, between Melbourne and Cocoa Florida.
There’s two in Brevard County. The one at Viera Blvd that you mentioned. And the other at St John Heritage Pkwy SE exit along I-95.
Yes Virginia... loves them! I-64 and US 15... the literal "Zion Crossroads." Think it's funny every time I drive pass that. Then I-66 and US 15 in Haymarket. They're building a new one in Charlottesville right now. I-64 exit 124 crossing US 250. The first one I've seen where the crossroad is under the Interstate rather than over. Say it'll be done by end of year. Be safe out there you all!
My first experience with DDI was in Spanish Fort, AL at I-10 and AL-181. I thought it was wierd at first but now I like it!
Two DDIs in my county of Brevard County, Florida. I-95 @ Viera Blvd. And I-95 @ St John Heritage Pkwy SE. Drove on both of them.
I was going to mention these. I have driven them both and I like them!
The I-196/US 131 interchange in Grand Rapids, Michigan is much like a diverging diamond except that the opposing lanes of US 131 are separated with bridges. This is a two-freeway crossing, and it works well.
The left exits are a big problem with that interchange, though. Slower traffic has to merge into the passing lane to take 131N to 196W, or the reverse. Also, this is less than a mile from the dramatic curve by The Intersection, hence why there are so many accidents here relative to other interchanges in Michigan.
i drove through a DDI and loved it tbh. paducah, ky exit 4. KTC built a DDI for exit 4 on I-24 in paducah, ky, felt great to drive on, especially when i had that nissan versa as its literally a breeze to get onto the interstate.
and i don't normally have problems missing the exit or taking the wrong exit, but it does make it safer for people who missed a exit and have to take a exit with a DDI in it to turn around as you don't risk a serious accident making 2 left turns to turn around, you still make them but you don't cross traffic to get to it, which is a plus tbh.
yes traffic that took the wrong exit and need a exit or two down, they would be forced to turn around at a local shopping center or someplace nearby, which can add to local traffic.
but maybe a roundabout a intersection or two down from each DDI might work?
@John Williamson actually its a brilliant design, and has drastically reduced traffic and accident rates everywhere its been built.
One is still being discussed for I-89 and US-2 in Colchester, VT (exit 16 just past the Winooski town line) but it's been in the planning phase for years.
The state of Michigan is implementing these all over the place. There are several in the Detroit area now. Big Beaver and I75, University Dr & I75, and a new one currently being constructed at 12 Mile and I75.
There is 4 on I-75 in Oakland Co, MI. 2 of them are fully built and the other 2 are under construction. They are part of the reconstruction of I-75 through Oakland Co. that is upgrading from the original design. The first DDI was built in 2015 and is Exit 79 University Dr. The other 3 are exit 69 Big Beaver Rd.(16 Mile Rd.) exit 65 14 Mile Rd. and exit 63 12 Mile Rd. I have driven straight through on the Big Beaver Rd. which was weird at first but have not used the ramps yet.
I glance over 12 Mile Road all of the time, which is closed east of Stephenson Highway. It’s progressing as they have the traffic signals up on that side.
Waves hi from I- 75/Big Beaver. People are still salty about DDI here.
I like these interchanges, there is one I sometimes frequent at I-35 and 95th Street in Overland Park, KS.
I just knew that one of the "downsides" to these interchanges is stupid drivers. Kind of like how people are anti-roundabouts because they don't know how to drive. However, that shouldn't be a deterrent to building more efficient and safe roads.
Another interchange I'm starting to see a lot is the Single point urban (SPUI). Are you making a video about that one?
Yeah that might be a good topic for a later video. Got a lot of other topics planned to make first though.
There is one at the US-21 and I-40 intersection in Statesville, NC. The intersection is nice but the signaling for the interchange is poorly done, the ground mounted signal isn't visible at all and the overhead signals are barely visible, even less so during the day.
I used the I44 / SR 13 DDI in Springfield a couple of years after it opened.
If you have a lot of traffic entering and exiting the Freeway, it works very well. Unfortunately, I expect State DOTs will overuse this design.
I have driven the new I 69 between Martinsville IN and SR 144. Both SR 44 and Henderson Ford road are 'dumbbell' exchanges. I think these are much safer than the original diamond exchange. It will be interesting how the SR 44 / I 69 2-lane 'dumbbell' interchange will hold up as traffic increases. One advantage of dumbbell exchanges -- it is very easy to reverse travel. In the event you got off at the wrong interchange, it is very easy to loop around and get back on.
I live in Charlotte, so I see these pretty often. I did go through one in Colorado Springs last year that kind of surprised me as I thought it was mostly an NC and GA thing.
Only about 10 mins from where I live we had a diverging diamond interchange built on Airport Rd and I-26 a little while ago in Asheville NC
There's one at College Dr. and I-25 in Cheyenne, WY. First time I used it, didn't care for it and it was a bit confusing, especially getting off from SB I-25 and not recognizing traffic coming from the right at the yield sign to go left. Now however, I like the design. Better than left turn lanes and arrows.
There a College Dr in Baton Rouge Louisiana
Indiana has built a handful as far as I'm aware. The first one was at Worthsville road and I-65. There is another on the northeast side of Indianapolis, and two more are near completion on I-65 near Whitestone Indiana. These two, (one being a conversion, and the other an entirely new interchange) are only a mile or so apart from each other.
Edit: After recounting, there are four completed DDI's in Indiana, and two nearly completed DDI's.
Yes, and at one point, there was supposed to be a DDI at the I-265 with SR 62 in Jeffersonville. INDOT dropped that idea and replaced it with a really badly-designed roundabout interchange.
@@NWIndianaElevators I never really understood why it was designed that way, but that clears it up nicely.
In Louisiana, there's a DDI at I-10/Loyola Drive interchange in Kenner
IIRC, Illinois' first DDI was I-88 at Route 59. I remember extreme confusion when it first opened, but it works so much better now - that Intersection used to constantly back up well onto the freeway, and it doesn't nearly as often now.
Yeah I think most people adjust to them after using them for a little while.
In Illinois l-90 at Elmhurst road, l-57 at hill ave and l-55 at Webber road have all converted into diverting diamond interchanges
Actually, I do know that the I-57 at The Hill Avenue in Marion was the first DDI in Illinois which was completed in 2015.
FDOT announced plans to convert I-10 Exits 5 and 7 near Pensacola to DDIs. Locals are freaking out about it, just as they did when FDOT converted a major intersection to a roundabout/flyover last year.
The Diverging Diamond Interchange is at I-95's Exit 22 in Lumberton, N.C. Another interchange is being constructed at I-20's Exit 190 in Grovetown, Ga.
There is one of these at the intersection of US 15 and I 64 in Virginia. It is absolutely amazing. A shame they can only stick them in rural areas instead of the Urban Areas where they are desperately needed.
I don’t understand why you say they can only put these in “rural” areas. The one at Zion Crossroads you mention (I-64 at US 15) is likely one of the most rural locations with one that I have heard of. It seems most of them are being put in very busy, suburban areas where there is clearly a significant need for them…
They have a DDI at 222/322 interchange in Ephrata, Lancaster County, PA. It messed me up at first, but once I did a little research, it made sense. I don't actually live in the area, so have no idea if it's helped congestion there.
LADOTD is building one at I-10/Loyola Drive in Kenner along with new flyovers to and from the airport.
I also believe Baton Rouge will have a DDI at I-10/Pecue Lane
I'm not 100% positive, but I believe the DDI that was installed near me was the first in Texas. I-35 & RM 1431 in Round Rock. Opened in November 2015.
It looks strange with Texas frontage roads.
I have used almost all the diverging diamond interchanges in Georgia and they do have many advantages however many people get confused as to which lane turns left onto the highway.
I've seen several DDI's here in North Carolina, including one at Gate City Boulevard and I-73 in Guilford County and one at Research Parkway and US 52 in Winston-Salem.
NC is on a building frenzy with them.
In my opinion, I think that they are not that hard to navigate. The signs are usually great since most are built in recent times. Another DDI is coming to GA at Exit 4 on I-185 (Buena Vista Rd). I watched the one at Exit 2 on I-285 get built. I like DDI's and I think they are better than traffic circles/roundabouts. I think roundabouts should only be used in residential areas because they're not the best for truckers. You should also do a video about roundabouts, and maybe all types of interchanges and intersections.
I'm mad I immediately identified the Charlotte area interchanges. But go through quite a few of them. Nice shot of the Ben Franklin Bridge at the end too.
Here in the Kansas City, Missouri area, in Lee's Summit, there is a dirvegabout. It is a diverging diamond with a roundabout on one end. I did not think that it would work, but it does, and flows nicely.
That sounds terrifying but hey if it works it works, right?
The design implemented quite nicely!
i live near the Raleigh Durham NC area and I've seen on the news where the DDI was being built on Airport Blvd by the RDU airport and on the Western Blvd / Blue Ridge Rd intersection in Raleigh. Being a former Uber/Lyft driver I was hoping to experience a DDI drive thru on one of those. Just last week though, I unexpectedly went thru a DDi in the Mebane Burlington area, making a left onto the interstate. It was a short wait at one traffic light. After that , it was a free flowing exit with no head-on interactions with another car, just as shown in this video.
I haven’t seen one road tripping yet but I grew up/started driving on Zion Crossroads in VA so nothing phases me lol. Love these breakdowns though.
Exit 407 on I40 in Tennessee has one. Works very well at keeping all that Smokey Mountain tourist traffic flowing
That where Bucees will be at
I don't know when you filmed this but Virginia also has a Diverging Diamond in Haymarket at I-66 and US 15.
I love how you used a lot of pictures here in Charlotte
They're building one of these at S.C. 290 and I 85. It's going to be cool to see the construction process
I've been through one at Gold Hill Road and I-77 one time when I was riding in a car with my brother and my dad. My dad felt like he was on the wrong side of the street.
Been building one for a while @ I 75 and SR 56 on Wesley Chapel Florida.
In Michigan, MDOT has built a ton of them recently:
I-96 at Cascade Rd in Grand Rapids
I-75 at University Dr in Auburn Hills
I-75 at Big Beaver Rd in Troy
I-75 at 14 Mile Rd in Madison Heights
I-75 at 12 Mile Rd in Madison Heights
I-94 at US 127/M-50 in Jackson
I suspect we will see more in the future at other known trouble spots on Michigan's freeways. I'm hoping that there are plans in the work to convert the interchange of I-75/US 23 at M-54/M-83 in Birch Run to one of these. Would really help.
Yes, there is a new ddi in Raleigh, the ground still hasn't even grown back
I live near Joplin, MO. There's one at I-44, Exit 8, Range Line Road. It seems to always do a good job moving traffic through. People walk on a sidewalk in the middle protected by barriers and it actually seems decent for them. Not many people seem to walk near the interchange anyways. I have witnessed a few people go the wrong way when going straight through, including a couple at me but thankfully in the other lane. I have seen many people make very odd and dangerous U-turns on the Range Line intersection. There's really no good reason for this!! You could get hit by traffic turning off the freeway that is not expecting you to suddenly illegally U-turn back in their path.
Virginia has two DDI's on US-15; at I-64 and at I-66. VDOT is currently rebuilding US-250 into a DDI at I-64 near Charlottesville. Why didn't someone come up with this idea sooner?
There is one at Zion Crossroads on I-64 in Va.
You should cover the omnipresent frontage roads found in Texas metropolitan areas as well as the Texas U-turn.
How do you feel about them? I thought the frontage roads were a pretty nice touch on Texas highways.
@@MileageMikeTravels I think they are ugly, in that they are usually lined with commercial sprawl that seems to go on forever. I would rather see forest along the highway, which you see in most other, especially Eastern, states.
I support DDIs, but they are not appropriate everywhere. A DDI is supposed to be at the I-66 Nutley St interchange but decided to do an unsignalized double roundabout interchange with loop ramps entering the I-66 regular lanes instead. This change made the most sense. I even heard of a proposal to change the cloverleaf interchange at the Old Ox Rd/Route 28 interchange to a DDI based on what I heard from VDOT about improving the Route 28 corridor between Frying Pan Rd and Sterling Blvd in order to reduce traffic weaving although auxiliary lanes are provided there.
We have one of these northeast of Indianapolis they built to test it, but I have yet to set new ones pop up
Diverging Diamonds seem very confusing. They are planning for one in my area at FM 60 / University Drive and Hwy 6 / Earl Rudder Fwy in College Station, Texas.
Indiana is starting to use those. The first that I have seen in Indiana is at I-69 and Indiana 1 on the northern fringe of Fort Wayne.
Yes, and at one point, there was supposed to be a DDI at the I-265 with SR 62 in Jeffersonville. INDOT dropped that idea and replaced it with a really badly-designed roundabout interchange.
Mike, we have three that I know of now in the Las Vegas area. There may be more soon.
There’s one that’s kinda on the way in Frederick, Maryland, between I-270/MD 85.
I have enjoyed the DDI of I-5 in Phoenix, Oregon. I think that’s Oregon’s first one.
Lexington was the first city in Kentucky to use those!
Harrodsburg Rd/New Circle Rd
My best friend REFUSES to drive on it!! Lol
She’s like 64/5yo
Haha yeah older drivers don’t want to adjust to the change.
Why hasn't France built more DDI's? The list you showed only has the two built in the 1970's. Could it be the pedestrian crossing issues?
I live around the New York City Metro Area So We Dont See DDI’s Around Here When I drove to Atlanta for the first time My First was The Pleasant Hill Rd that was shown at 0:14 I was so confused. But the more I went on it i started to like it.
The interchange at 1:15 is close to where I live.
In western Pennsylvania we have clover leaf interchanges. They suck. And are very dangerous. Some have less than an eighth of a mile get on ramp.
There’s one in my state and boy do people fly. The lights are synced so you could step on it
Lumberton NC, Exit 22 off I-95 for US 301.
NC is building tons of them.
I live in Louisiana
PA where I grew up has one
you can easily take a U-turn on the highway. You just turn left twice. Am I missing something?
Diverging Diamonds are okay I guess. The biggest problem is that most DOTs aren't designing them correctly. A majority of DDIs use no-turn-on-reds at most, if not _all_ , merging movements, which significantly impairs traffic flow.
VDOT installed a DDI at the interchange of I-66 and US-15 in Haymarket, and that intersection has become a total traffic flow trainwreck since. I avoid that intersection at all costs.
Returning from South Carolina to Pennsylvania, I used US 15 as an alt to the ridiculous traffic on 95. Went through this exact DDI and didn't experience any problems. Ofc just a one time experience but it was on Labor Day where traffic would've been at a peak.
I use the Haymarket DDI several times a week. I've never had a problem traversing it, nor heard anyone refer to it as a trainwreck. It's much better than what was there before, especially for traffic from southbound Rt 15 heading east on I-66.
@@gr8deadfan75 It's _especially_ bad for motorists heading north on US-15. The interchange itself should not have been a DDI given that both I-66 and US-15 are major through routes, so both need to have some degree of free flow, which DDIs do not provide.
@@Mapmaker1559 I agree the no turn on red is unwarranted at that intersection however I’d argue the the US-15/John Marshall Hwy intersection right next to it is far worse. I end up sitting at that one for far longer no matter which way I approach. It’s cycle and timing with the other close lights is all sorts of messed up
@@zacharyyoumans9614 I agree, both intersections are really bad, and yes the intersection of US-15 and VA-55 is very poorly timed as well.
Louisiana where I live
They got DDI in Texas too I'm not sure where
The Austin district of TxDOT has been retrofitting existing interchanges with them for several years now. They've also built a new one from scratch at Mopac and Slaughter Ln in south Austin.
I think they have one in Louisiana but don’t know where
There's one in College Station as well that opened in 2019/2020 I believe
Where are the others in the world?
My solution for the confusion from driving temporarily on the left side of the road: block the view of the opposing traffic on the other side with a barrier.
There's a diverging diamond near me that does this. It works.
Great idea
There's one at I-66 and US-15 in Haymarket, VA. It's made it safer and flow better.
The interchange at I-66 and US-15 in Haymarket does not flow better since becoming a DDI. Especially for traffic heading north on US-15. The interchange has become a nightmare for traffic flow. I've gone through it several times, I can personally attest that it is _not_ good. Maybe DDIs work well at other intersections, but that interchange in particular should _not_ be a DDI, one of VDOT's worst mistakes ever.
@@Mapmaker1559 eh for me when I go through it the biggest issue is the timing of the lights.
@@willn703 Exactly. The extremely poor signal timing is the biggest reason traffic flow through the interchange is so bad. Even if the interchange doesn't congest terribly, the signal light delays are awful, and that factors into a measure of traffic flow.
Terrible for pedestrians though. Just wish they wouldn't build these near urban interchanges.
Only at slip lanes. Otherwise, it is less delay and less crossing distance for pedestrians.
The diverging diamond interchange is bad for pedestrians.
Only at slip lanes. Otherwise, there is less way and shorter crossing distances for pedestrians.
These and roundabouts are the dumbest traffic additions ever...
DD are just another example of self-indulgent incompetence and the lack of any real innovation in the road bureaucracy. Express way crossings should have...wait for it...0 (zero) crossings. The solution is shockingly simple...anyone???????
And no, the answer is not a round-about, though that would be way better then a DD.
Expressways are not limited access. And if the option involves less money, fire away.
In my opinion it is a stupid design. Tried it didn't like it. Will avoid it if at all possible.
Round about is much better.
Roundabouts lose efficiency at 25,000 vehicles per day (45,000 for dual lanes). Not to mention the added cost for right of way that would still be inefficient for the large volumes this interchange would handle. Roundabout interchanges are best for rural areas.