Would you drive on this FLIP-FLOPPED interchange? (It's better in every way!)

[@PracticalEngineeringChannel]

Well, I'm taking this topic off my list of video ideas ;) Couldn't have been done better. Awesome video.

[@tompeled6193]

Hello.

[@DavidRiegner]

Can we get a collaboration episode with you two? Love both channels!

[@Marween]

I like your vids as well!

[@MarkReviews]

I love seeing game recognize game. Both your channels are phenomenal!

[@xxbighotshotxx]

I don't think you have to see it that way. The KZbinr AustinMcConnell did a well received video on the same subject and I still enjoyed this video!

[@shaggyfilms]

My mom thought I was autistic when i was a child because i was obsessed with roads and road signs. I still am today and i feel like I have finally found my people. Thanks Rob

[@startreking]

My town got one, it removed horribly programmed lights. I love that.

[@jfbeam]

The problem was the idiots who programmed the lights, NOT the road itself. I see this crap everywhere; no one does a good job setting up lights. My least favorite thing is the bullshit of a left turn lane _and light_ that just flashes yellow all the time. It takes an entire cycle to give turning traffic priority, even when there are sensors to tell it there are approaching cars rendering the flash cycle useless. And then there's the morons that think turning a dual-turn lane into a single lane most of the day will actually speed up traffic. (no you f'ing a-hole, parallel streams of cars moves more cars than a single stream. Of course, this does require the lights to be programmed to allow more than 4s for traffic to move.)

[@sleetskate]

@@jfbeam except with dual lanes you can get stuck behind a red arrow when theres NOBODY COMING, which makes a single lane faster during the 20 hours of the day when the roads arent jam packed. You cant have an FYA with dual lanes.

[@jfbeam]

@@sleetskate Try more like 8hrs a day. The issue with f'ing flashing-yellows is the programming. They flash when there's traffic standing at the opposing light. The result is an entire light cycle that turn traffic can't move. When there's a car on the left sensor and opposing through sensor *NEVER* go to flash mode. It doesn't matter if it's just one car on both sides, *NEVER* go to flash. (hint: there's never just one f'ing car; even if there's only one on any sensor, there'll be 50+ approaching the light.) And yes, multi-lane flashing is possible, just rarely done due to the general volume of traffic at such crossings.

[@sleetskate]

@@jfbeam that still leaves 16 hours per day where traffic is light enough to not warrant red arrows. red arrows are incredibly wasteful, due to wasted emissions from unnecessary idling when there are gaps in traffic that could have otherwise been turned through, along with time wasted stuck at a useless red light. This is exactly why right on red became a thing. sounds like a problem with the light programming, not the FYA itself. FYA is nearly identical to the 5-headed signals that can display both arrows and circles on the same head, aside from the fact that it can operate independently of straight traffic. This is where the FYA/red circle combo comes in: Oncoming traffic is finishing their protected turn phase, but this doesn't stop you from turning left, assuming traffic allows. The main problem with two lane FYA is visibility from the outer lane, not traffic volume. Outside of instances where streets dead end into parking lots or such, where oncoming traffic is minimal, dual FYA is just not feasible, because its impossible to see oncoming traffic from the outer lane.

[@Trainfan1055Janathan]

I remember the first time I saw one of these as a truck driver. I asked my trainer, "so am I supposed to drive on the left side?"

[@mauidano13]

Depends, how many cars can you mow over?

[@michaelmccarthy4615]

Yes...

[@jimdigitalvideo]

Only if there are no witnesses. 🤣🤣🤣

[@davidjones-vx9ju]

never are opposing lanes not completely separated...you don't drive on the left side. the bridge lanes are moved

[@familykaplan1341]

There is one at Glades Rd and I-95 in Boca Raton, Florida and is spectacular and will prevent many accidents!

[@WhyBeNick]

I live in Springfield MO where we got the first one in the US. People whined and cried about it during construction, but quickly realized that these things are amazing. We now have several of them throughout the city.

[@indigo1324]

I remember visiting extended family in Springfield in 2015 and I was so confused as to why the interchanges switched sides since I had never seen a DDI before that. Later I learned what their actual purpose is and how they work and now I love them! I live in the Chicago metro area and there have been several of these interchanges added over the last number of years, which I think is great.

[@Robbie06261995]

Greetings fellow Missourian. Here in STL we’ve got a few of them built so far. Dorsett road & 270 as well as a couple along 70 in St Charles.

[@kpresnell45]

From Springfield as well, Springfield has 5 now with a 6th in Ozark, just 1 exit from Springfield. I love them and they work great. Early days I did see people go the wrong way, but now, so much traffic goes through, it’s nearly impossible to mess up.

[@tonyhogg9839]

I live close to that first interchange. They had just worked on that bridge about a year before. I was confused as to why they had to work on that bridge again, so I looked online and found out what they were doing and immediately thought it was a really good idea, because I knew how badly traffic backed up because of people turning left to get on the highway. That center turn lane could only hold six cars before they start blocking the inside lane that goes straight. It was a problem. Now that problem is gone. No more traffic backed up from I-44 all they way to Kearney (on Kansas Ex) in 5 pm rush hour which was an almost daily thing Monday through Friday.

[@jakebleesmith5370]

I live in a small town in NC and we have one I didn’t know they was this rare

[@brianloper6669]

Yes, now we need more roundabouts. I'm tired of stopping at 4way stop signs from 10pm-5am in rural/suburban areas when nobody is there

[@coherentpanda7115]

When I came bac kto America after 8 years living overseas, my first through driving in town is why the hell are there 4 way stops every single intersection, it's absolutely annoying. America definitely needs to mass produce roundabouts.

[@UDumFck]

In Atlanta, DDIs exist and are going in everywhere. People get used to them quickly. Another newer design is the double roundabout, where there is a roundabout on each end of the bridge. Seems to work pretty well too (for 2 lane crossover streets).

[@richardcleary9107]

We have 3 round about a in a row....hate 'em

[@nthgth]

Seems like it might cost less to just replace half those stop signs with yield signs

[@Zuconja]

@@nthgth Or imagine two stop signs and two right of way (diamond) signs? Or imagine just two stop signs (no sign means you have right of way)? This is how we in Europe deal with this problem.

[@custardo]

A choice quote from the UDOT report: "There are no viable transportation alternatives to cars for residents of West Lehi, Saratoga Springs, or Eagle Mountain." Well done Utah, well done.

[@scottanno8861]

Saratoga and Eagle mountain need expressways at the very least, if not straight up bridges.

[@adamt195]

Classic state DOT. Just ignore alternatives.

[@hacklaurent9412]

Sarasota traffic is not funn

[@scottanno8861]

@@AliciaMcIntire LOL you look and sound like a Karen yourself

[@protorhinocerator142]

This all sounds great until you need to do road maintenance on the bridge and switch people back to the original lane. Now everyone is double confused.

[@MicahPotts]

4:58 if you have ClosedCaptions on it describes the music as "Inexpensive, but surprisingly good, disco stock music" lol. Props to whoever put that together!

[@jefffinkbonner9551]

That’s bloody brilliant! 😂😂😂 Kinda sounds like Another One Bites The Dust by Queen, even though that song didn’t come out till 1980.

[@pigletshut]

Try Technology Connections where he labels the ending theme " smooth jazz" in every video. Gets me every time.

[@ebob1967]

I think the reason people are not turning left on red is that the signal is a red arrow. Around here, that usually means that you cannot make an unprotected left turn. I think it would work better with a solid red (not arrow) and a flashing yellow arrow.

[@pleasedontwatchthese9593]

I admit if I saw that It would take me a while to notice that I could turn

[@Finn-sm3jf]

The sign changes the meaning of the red arrow to mean turning after stopping is allowed

[@SparkyRoosta]

@ebob1967 I agree. The red arrow feels like a hard no.

[@SparkyRoosta]

​@@Finn-sm3jf It might take some time for the extra sign to make sense. In my driving school past, a Red Arrow was a hard no, and I would have a hard time with that.

[@mrcryptozoic817]

You're right, that arrow should be yellow, not red. Red is sending a mixed message that looks like a control box error.

[@RowanHawkins]

The one in Rochester was the first one in NY. It has a high center wall under the bridge and frankly helps enforce traffic exiting the interstate it ends before the cross point so it doesn't block vision there. It also helps with idiots leaving their high beams on coming off the unlit 3digit interstate onto a lit city street.

[@mjrc123]

This channel is still so massively underrated.

[@Arjay404]

I actually really like these, they are very simple, just follow the arrows/lanes, they are safer and from a Cities Skylines player perspective I love that they are "small".

[@mrniusi11]

Hell yeah, skylines traffic savers

[@krisswolf2011]

“Left on red after stop” problem can be solved by just making the red arrow blink instead of a solid red

[@paulwoodman5131]

Yes

[@GreenJeep1998]

Or even blinking yellow.

[@thaintriguing1]

NC has blinking yellow lights

[@krisswolf2011]

@@GreenJeep1998 I’m not sure about yellow.. i think blinking red means same thing as stop sign, “come to complete stop, then go”? I think Blinking yellow means same as yield sign, “yield to other traffic, but otherwise proceed”, you don’t have to stop at all if you don’t see cross traffic

[@chernobyl68]

The red arrow prohibits a turn, so the signal conflicts with the sign. It should be a red ball instead.

[@JP-su8bp]

The first time I saw one of these was when I exited for fuel. My first thought was, "Who thought up this crazy {insert bad word here}?" While filling my fuel tank, I watched vehicles travel through the intersection and noticed how few had to stop. By the time I'd replaced my fuel cap, I was thinking, "Who thought up this brilliant {insert bad word here}?"

[@think-forge]

The production and the jokes are next-level! On a more serious note, when do you plan on releasing a review on the Mitsubishi Mirage?

[@petuniasevan]

They put in a DD intersection in Appleton Wisconsin recently; it's at highway 441 on Oneida Street. I was suspicious of it at first as to its ability to control traffic as advertised (unlike all the interchange embedded traffic circles around here that are poorly designed) but the DDI setup is working so far. Great video, Rob; I didn't even know what the nomenclature was for this setup before I watched this.

[@DblIre]

Familiar with it. BTW, I like the roundabouts, it's the people that don't understand them and use them properly that's the problem. Like stopping in the middle of them.

[@kingsford3657]

I was just thinking the other day “when will we get another RGR video?” And I clicked as soon as I saw the notification 😃

[@HendrixColtrane]

The wait is worth it, majorly informing, current information, and Rob goes the extra mile with production. Talking about an interchange in Utah - goes to Utah

[@vizender]

19:48. At this situation, as a French guy, I’ll just make the two intersections roundabouts. The freeway exit is always the busiest, so the roads from the DDI are also the busiest, and roundabouts are great at dealing with this kind of imbalanced traffic, and it seems there is enough room to put 3 lanes roundabouts at least

[@traffic.engineer]

Given that America has much greater car ownership, the project volumes would be much greater than upper threshold of roundabout efficiency. Roundabout interchanges work much better in more rural and suburban environments.

[@vizender]

@@traffic.engineer And that’s where I disagree. Roundabouts handle way better asymmetrical traffic than basic traffic light does, because it allow for a constant flow of traffic

[@JETZcorp]

@@vizender You have to take into account that a freeway interchange would either require 2 roundabouts in a dumbbell configuration, or 1 very large and very expensive one. Roundabouts reduce in efficiency as lane counts increase, and a 2-phase traffic light is MUCH more efficient than the usual 4-phase light or 2-phase with left yield that roundabouts are typically compared to. The entire DDI system acts as a coordinated 2-phase system, with a couple continuous flowing elements (eg. right turns) for extra flavor. All told, I think a DDI outperforms a roundabout in this application, especially given the cost. Roundabouts are excellent for surface-level crossings though.

[@MarloSoBalJr]

That was my first thought as well. A roundabout can prove to be beneficial

[@MarloSoBalJr]

@@JETZcorp I think he meant adding two roundabouts at the two frontage roads that lead into the DDI interchange of the freeway.

[@bradybirdy9243]

It's so cool watching your videos as a SLC local, I worked as a driver for a couple of years and spent a lot of time traveling back and forth through the valley. Spent a lot of time thinking about how these roads work, so seeing your detailed explanations while using those same very roads as examples is really awesome! Thanks for the great content man, keep it up!

[@forrestihler504]

Loved the Doug DeMuro reference at the beginning. Great video as usual. Utah’s neighbor to the north in Pocatello Idaho got one several years ago. Works great. Now Rexburg Idaho is getting 2 of these at the same time in 2 years. It’s needed badly, they are taking 2 diamond interchange with NO traffic lights and switching them both to DDI’s. It’s definitely long overdue. Very exciting. Can’t wait to see the finished product.

[@stevecooper7883]

In American Fork, Utah, as shown in the video, the interchange still can't handle the amount of traffic. They are over engineering the place.

[@avengedmetal]

I don’t get excited for videos from other you tubers like road guy Rob. His videos bring me great joy always to learn about something as seemingly mundane as traffic or roads but made so interesting to learn about while watching KZbin thanks to him

[@alec4672]

I think nobody goes left on red cause it's a left arrow. My generation and older has basically been taught red arrows are king. If the arrow is red it's more important than even just a round red. The arrow should flash yellow instead of relying on a "left on red allowed" sign. By my understanding a fishing yellow is the same as a yeild which is what you're supposed to do.

[@EnjoyFirefighting]

16:27 being from Germany I'm well sued to traffic lights on the near side. It really is NOT that much of a problem. However this situation being a problem can be reduced if traffic lights aren't only high up above the intersection, while both above the intersection and a 2nd one being half-way up the post and thus being perfectly located for drivers up front (car, van, truck drivers) to see it without the need to twist their neck We don't have DDIs in Germany at all. Depending on the size and traffic load of a highway access it wil be controlled either by traffic signs alone with the crossing road being the priority road having the right of way over the exit lanes coming from the highway, or there are traffic lights which are well-timed, either close to or definetly as constant flow intersection. My issue with a DDI would be that you can't keep up flow in both directions of the crossing street at the same time, as they stop each other at one of the two large conflict points I also like the Swedish approach of elevated or lowered large scale roundabouts providing easy and fast, constant flow highway access points without any traffic lights and without any of the serious conflict points. No traffic lights make the entire thing also much much cheaper ... and it also works in dense urban environments with lots of traffic

[@RealestUrbanism]

Both big roundabouts and dumbbells with 2 small roundabouts are great! The dumbbell is the cheaper (especially for retrofits) and more compact option that also gives approaching cars a chance to u turn, so you can ban left turns on the intersection leading up to the highway interchange.

[@princekamoro3869]

If you think about it, a diamond interchange is just a really skinny roundabout (with vehicles "circling" around the median on the bridge). But then the signs give priority to vehicles entering the "circle," which is a big no-no for roundabouts.

[@CarsMutley1995]

I'm a traffic engineer in the UK and have loved DDIs since I learnt about them. I went out of my way to model one in the microsim software Vissim to really investigate how they worked. I hope I get to work on one someday!

[@DrJams]

Awesome. You should make a KZbin channel about UK road engineers

[@afthefragile]

Round abouts are superior however. No traffic lights just go.

[@vxcmdr]

The state of Queensland “QLD”, Australia have already constructed 3. Interesting idea to try to solve traffic in a cheap way. At first it seems confusing that you have to swap to the right side but just follow the lines.

[@jefffinkbonner9551]

So you switch to the correct side, then 😉

[@AllAmericanGuyExpert]

These are amazing. Their introduction into a small city in the middle of nowhere in the US gave me no clue as to how rare they were... I just happened to live nearby. I occasionally travel what is essentially the first 5 in the world, and they're incredibly efficient. I've never been "stuck" at one. They always seem to move faster than regular overpasses. The left turn onto the freeway without a traffic light is like gold.

[@mattpotter8725]

@@jefffinkbonner9551 I know this is just a joke, but I think thinking of switching sides to what either citizen of the country would call the wrong side as it's done in the video is wrong here. If you think of them as feeders for the interstate/freeways then they've already become part of that road by that point and so are in the right side already for that road. It might not be for the road going straight across, but I think this solution is mainly an attempt to better get people off the busier road.

[@newsgetsold]

Only one is built so far. Other 2 still under construction and maybe not finished until 2023. The first one took 4 years to build! Everyone complained while it was being built. But now everyone loves it.

[@amorphousblob2721]

There's one of these near me. Coming off the highway and turning left, when the road crosses back over to the right side, there's a light, and it's ALWAYS red. And it _stays_ red FOREVER. When I end up here it's usually the middle of the night, so I'm sitting there at a red light waiting for nothing except the illegality of running a red light. If only there was a bridge instead of that intersection. Nobody wants to turn there, so having an intersection instead of a bridge does nothing but forces there to be a stop light.

[@chriskeller676]

I remember when they built the first DDI here in Springfield, MO. It was the first in the country and everyone was freaked out. A few people drove the wrong way at first somehow 🤷🏻‍♂️. Now, they're great. We have like 6. We really like them now.

[@eraldway]

It gives me chills at how good these interchanges are.

[@walterclements_]

you mean how bad and unnecessary they are

[@eraldway]

@@walterclements_ no. At how good they are for traffic flow and accident prevention. If you think these are bad and unnecessary, please do us and your self a favour and surrender or your drivers licence.

[@jrdnwhtny1]

These are terrible. Because you cannot turn right on red where I live, the traffic backs up onto the interstate. Way more dangerous.

[@eraldway]

@@jrdnwhtny1 there are no lights on these for you to turn. The light is for thru traffic only.

[@FinnishNationalist123]

@@jrdnwhtny1 statistically much safer

[@RC2225]

Here in Switzerland there are some exits which are ending in an large roundabout. Often they are on the newer motorways or are retrofitted when the cross street is wide enough. In one example near where I live it goes so far that its just a long squished roundabout. Im really looking forward to the next video.

[@erigabu1]

In Hungary is a same, in a newer in/out road in a highway lots of time (if the cross transit is big), using roundabout. If the cross road is a "very big" in transit, then using "turbo roundabout".. but from this last type not have much... I like better the roundabout because no need traffic light.

[@SeverityOne]

@@erigabu1 If you like turbo roundabouts, go to the Netherlands. They invented them, and have around 75% of all turbo roundabouts worldwide.

[@traffic.engineer]

America has many double roundabout interchanges and prefers them, but the traffic volumes at this location are much too high for it to work efficiently.

[@hagelslag9312]

@@SeverityOne Yep, wanted to comment this one. I drive past 7 roundabouts daily and I barely ever have to stand still because it's so flawlessly done, everything can just keep driving.

[@TheBenghaziRabbit]

we have one of those here and at first it had me feeling uneasy but you get used to it.

[@AmtrakProductions]

@9:56 we actually banned turns on red at our DDI so pedestrians had a protected walk. A new light we are working on will use a blank out sign to do this only when a pedestrian is crossing

[@AmtrakProductions]

Yay pedestrian and bikes!

[@pleasedontwatchthese9593]

I think it depends on the type of DDI. They showed in the video but on some of them you walk in the middle which frees the left turn up from peds.

[@AmtrakProductions]

@@pleasedontwatchthese9593 yeah then it's good to have the turn on red except if there is a BL conflict

[@traffic.engineer]

States like Missouri and North Carolina legally does not allow left turn on red anywhere.

[@karlrovey]

@@traffic.engineer Some of the DDIs in Springfield allow it (or did at one time). It was explicitly noted on a sign.

[@mabus42]

I live in Indiana... and suprisingly they have a few of these intersections at junctions with I-69. Also, lots of roundabouts.

[@deelowe3]

Your videos are getting so good! Keep it up Rob. Can’t wait for the next one.

[@TheRealPSKilla502]

Maybe tone down the humor a little though, it got pretty cheesy at times

[@deelowe3]

@@TheRealPSKilla502 I think it’s great.

[@jefffinkbonner9551]

@@TheRealPSKilla502 You must develop your palette as a cheese connoisseur to properly view Road Guy Rob videos

[@nthgth]

SPUI - hey, there's one of those near where i used to live on Long Island! Rt 25 and Nicolls Rd I believe. The amount of traffic there, and with Nicolls being a 4-lane divided highway, no wonder they went with that design. Never thought about it before now but I always knew it was an unusual left turn there.

[@cat-.-]

The editing, music, pace and production is just as good as the topic itself!

[@jessicaarchibald6961]

In the past month I have come across TWO of these "in the wild" (completely unexpectedly just driving around in new locations). Both of which were in the mountains (one in Asheville, one in Denver). I was so happy I had seen this video because otherwise I would have been REALLY confused how to navigate it. Point of the story is you're awesome Rob & super appreciated!!

[@insertchannelnamehere632]

There are two in CO, neither of which are "in the mountains" (Denver and Grand Junction), they're near the mountains

[@Technochocolate]

In addition to the "left on red after stop" sign, the left arrow should be flashing red instead of solid red because that's how lights behave when you should treat them as a stop sign. 9:15

[@RyMcQ]

I think a solid red (non arrow) would work as well, but you are right. A red arrow pretty strongly says "Do not turn" even when there is a sign right next to it saying otherwise.

[@robertnino8997]

What about a flashing yellow as caution because when I see red I think stop

[@AndrewMeyer]

Yep, the signal was contradicting the sign. You can't turn right on red into a solid red arrow, so why would you do it for a solid red left arrow? Should have been flashing.

[@AndrewMeyer]

@@robertnino8997 Flashing yellow means yield, which is not what we want here. Flashing red means "stop, then go when safe", just like a red stop sign.

[@robertnino8997]

@@AndrewMeyer true I think hopefully with time people will understand the intersection

[@AutismFamilyChannel]

Thanks for letting me know why the roads seem so crazy in Utah now 😂

[@bar10dr]

I’m not sure why I find your videos so interesting but I could watch this all day long

[@pilgrimwanders]

We got one of these put in on an Interstate exit where I live in rural east TN. It took a while for us to get used to it, But we spend less time at the red lights and there are way less accidents

[@jamesforrest9837]

your entire channel has great style, pacing, and writing, and content. better videos than 99 percent of other channels!

[@thewanderer416]

Agreed! Few other channels come close. Rob deserves way more subs

[@albireo2990]

I kinda want a variant of these in the UK. Obviously instead of going from right to left it would be left to right here, but it’s still good.

[@reddcube]

SPUI near me is great. Especial because ambulances have to go straight though all the time. The only weird thing I've notices is that there are many U-turns at the next stoplights, because people aren't expecting the entrance ramps on the left side.

[@JETZcorp]

My city (Vancouver Washington) has SPUIs everywhere, and they're common enough that everyone gets it. Crossing the river back into Portland with all it's conventional diamonds is just painful (as is everything traffic-related on the Oregon side).

[@blitzn00dle50]

SPUIs are the best interchange

[@alexflosho]

Huh, I didn't know that one was #5 in the world. I've driven over it countless times but I've never known that. Neat!

[@OkieOtaku]

I was just talking about these with my mom, because ODOT is looking to put one of these in my home town Tulsa, not far from her house. I love them, seen and drove them many times

[@AsloAso]

Here in Australia we use either a single or double roundabout interchange as all the traffic goes in one Direction so there no traffic lights required

[@j.s.7335]

I never understood the advantages of these interchanges. Thanks for the great explanation. And, thank you Patrons!

[@unfvzedmak]

we have these in central florida, they work miracles.

[@thomashendricks9774]

I've loved DD since first learning about them several years ago. However I was unaware of one being in NY. Just discovered from your video there is one in Rochester NY, not to far from me in Syracuse NY. I'm going to run out there and check it out.

[@MrTwostring]

I think Rochester's was one of the early ones. I remember a lot of controversy putting in an "experimental" intersection. I had some opportunities to drive through it a few times a few years back and found it far more intuitive than the controversy suggested.

[@TheJttv]

@@MrTwostring first in the state, i think it was within the first 15 in the country. Still dont think that location need it. They claimed there was like several hundred accidents there, but i never saw one.

[@nthgth]

I'm also in Syracuse (3 roundabouts within a few miles of my house lol) and thought the exact same thing

[@thomashendricks9774]

@@nthgth I have a video of two of the three roundabouts on my channel. kzbin.info/www/bejne/oIvTcmSKiZhnapI

[@racer72]

Drove on one of these about a year ago. I had no problems, many other's did. The state of Washington is installing one at the I-90/Highway 18 interchange east of Seattle. The backups at that interchange can be epic, especially on Sunday afternoons.

[@TheCloakedTiger]

I really like DD interchanges. Especially in a truck! More room to make my turns and less chance of a accident and easier freeway access. Rochester has a ton of them now.

[@RealestUrbanism]

what do you think of ddi vs dumbbells (a diamond with 2 roundabouts)

[@RaindropsBleeding]

That's actually why I love them too, despite not being a truck driver. When I first learned about them, the video talked about how easy left turns became for truck drivers, where a left turn turn onto a highway was considered one of the most difficult maneuvers for a truck driver.

[@edwardmiessner6502]

@@RealestUrbanism I think large rotaries are better than either

[@TheJttv]

I only know of the one in brighton NY is there more? Or different rochester

[@JohnDlugosz]

0:45 Did you notice that the design on the metal fence matches the Diverging Diamond motif?

[@jayamber4448]

One thing you didn't mention: DDIs make it very easy to perform a u-turn back onto the motorway, which means it's possible to take advantage of limited access junctions further up the road.

[@joaodasilva8008]

I saw several of this Diamonds 20 years ago in Monterrey in Mexico

[@mdrichards]

It seems like that "left on red after stop" would be less confusing if it used a flashing red circle instead of a red arrow.

[@Default78334]

Or a flashing yellow arrow like you already see lots of roads with a protected left-turn phase.

[@spunker88]

They are using the wrong light and that is causing confusion. Usually you are not allowed to turn with a red arrow, you have to wait for it to turn green before proceeding. They should be using a flashing yellow arrow as that means you can turn after yielding.

[@ebnertra0004]

Flashing red arrow would be even better, since that implies you have to stop first. There is a light around here that uses a flashing red arrow for right turns, since they're not always allowed

[@traffic.engineer]

Utah prohibits left turn on a red arrow except when a sign permits it.

[@nthgth]

Yeah it really should be flashing red arrow, that would mean exactly what those signs say but without text so simpler and quicker to process.

[@theghostwheel5137]

I have one of these a few miles from my house. It was a long and extremely expensive project for the city, and it just causes more confusion and traffic delays than the normal intersections and on-ramps it replaced.

[@mrniusi11]

What's the average IQ there? 80?

[@nathanacreman632]

This intersection nearly got me in a massive wreck when I was driving through Nevada for the first time in my life. Maybe if you're already familiar it would be safer, but if you've never seen it, there's a HUGE chance you'll get confused and wreck.

[@gamtax]

Yeah, saw one video that points out the flaw. Unfamiliar driver is the weakness. Proper road guidance and road signs are pretty crucial for this design. Either way, it is really efficient.

[@swmovan]

@@gamtax If I remember correctly, Springfield had signs to tell drivers what was ahead. Whether they still do, or other new ones do, I have no idea.

[@mavfin8720]

@@swmovan The lines are painted in such a way that if you follow the painted lines, it's almost impossible to screw up. If you're not paying attention, as a driver, well, that's on the driver, isn't it?

[@ken9720]

I can't even comprehend how anyone could get confused with these interchanges as everything is divided by concrete meridians, the intersections are at angles to each other and the traffic lights are set so you can only see the ones facing your lanes of traffic. So unless you were NOT paying attention, asleep on your feet or just plain dead there should be no reason for an accident to happen.

[@nathanacreman632]

@@ken9720 if ur not expecting it then the natural response in my mind anyways is find the right side or lane and get in it, even if it looks out of place. If all you’re life you’ve only ever driven on the right, it would be weird to now cross into the left at an intersection if you didn’t realize it was intentional.

[@TheLongjohntim]

As a truck driver I have driven through one of these a time or two. The first Time if freaked my out just a bit. I parked at the truck stop and watched as other drivers like me had never gone through one It was fun watching.

[@Arlae_Nova]

I want to turn your attention to the roundabout: another great option and tool for interchanges. Having more than one option for interchanges in the engineering toolkit is great, and there are definitely places that benefit from a roundabout more than a Spoi or a ddi.

[@stevieinselby]

In the UK, roundabouts were standard for almost all motorway interchanges where full grade separation wasn't needed for a long time, and including modified roundabout interchanges with freeflow links still make up about two-thirds of all motorway interchanges here ... but they have fallen out of favour recently and new interchanges are more likely to be dumbbells than full roundabouts. The main advantage is they are cheaper to build, but they have lower capacity and unless you block off the unnecessary parts of the roundabout they are likely to be less safe. But at the same time, many busy junctions are now finding that roundabouts are struggling to cope with very high traffic volumes as well. I would love to see DDIs make an appearance in the UK, but so many interchanges are not just between the mainline and _one_ cross-street that the number of locations where they would be suitable is quite limited.

[@RealestUrbanism]

@@stevieinselby dumbbells are great! Im bummed rob didn't compare dumbbells to DDIs. dumbbells are safer for cars and don't need a traffic light (although DDIs don't necessarily need a traffic light either if you put a yield for entering cars on the crossover)

[@traffic.engineer]

America builds roundabouts in many locations, but roundabouts have an upper threshold for volume where it is no longer efficient. American DOTs prefer roundabout interchanges in less dense urban and rural environments where they are much more efficient and worth the upfront cost. The traffic volume at this interchange is well beyond that threshold. And America does NOT build traffic circles, which is functionally different from roundabouts.

[@Shadowfax-1980]

This is the only channel that realistically examines road transportation in America and doesn’t devolve into pie-in-the-sky dreams of a magical high speed rail network that will pop up overnight or analysis that starts off with “In Amsterdam they do this…”

[@snarwars]

i think i get the reference :'D

[@justanotherguy8791]

we have one in Florida and it is went from 30+ minutes to cross interstate to minutes.

[@vijay-c]

Seems like roundabouts would solve that traffic issue at the end of the roads you mentioned, rather than reconfiguring the DDI. Not really sure what the DDI accomplishes that roundabouts wouldn't, execpt being cheaper by using the already existing diamond. But it's cheaper at the expense of safety.

[@tommitchell2055]

I saw a video a few years ago about a diverging diamond. So when I finally found one at i88 and IL 59 near Naperville, I was kind of sad that I didn't get a virgin experience driving on one for the first time.

[@jefffinkbonner9551]

“Hey Siri, play “It Feel Like the First Time” by Foreigner” I got a route with destiny.

[@cdvideodump]

@@jefffinkbonner9551 Sorry, I didn't quite get that. Did you mean "It Feel Like The First Time" by Urgent (a Foreigner cover band)?

[@jack002tuber]

We have some divergent diamonds and roundabouts here. What we still lack in 2023 is a light that knows I AM HERE. There are no intersections with lights anywhere here in SW MO that see a car coming and give it a green when all other directions are clear. How is this still not being done?

[@shiina_mahiru_9067]

Well, what if DDI means "double-decker" interchange? That is, we put one direction on the upper-deck and the other direction on the lower-deck. Then I think you can eliminate ALL traffic lights and reduce contact points. (P.S.nevermind, it turns out this already exists, called the stack interchange)

[@ErdTirdMans]

Indeed. Stack interchanges are things of beauty!

[@brendantschappat1371]

The particular design you are describing here I think would actually be a diverging stack interchange, however, traditional stacks do the exact same thing with less confusion.

[@heretolevitateme]

That's a "Double crossover merging interchange" or *DCMI*. Also a bonus, is that you can have the exit ramps merge "in the middle" which eliminates the weaving problem of a DDI.

[@FadkinsDiet]

Whats the construction and maintenance cost of a stack interchange?

[@NWIndianaElevators]

Great video, Rob! We have four DDIs that are operational in Indiana with two more under construction. 1. I-69 at SR 1 (Dupont Road) in Fort Wayne - conversion from a diamond interchange 2. I-65 at Worthsville Road in Greenwood - new interchange 3. I-69 at Campus/Southeastern Parkway in Fishers - conversion from a diamond interchange 4. I-70 at SR 39 in Mooresville - conversion from a diamond interchange 5. I-65 at SR 267 in Whitestown - conversion from a diamond interchange (under construction) 6. I-65 at CR 550 S in Whitestown - new interchange (under construction)

[@thisispodracing]

I really like DDIs as a driver, but the high number of "slip lanes" and the addition of left turn on red after stop can be dangerous for pedestrians. Edit: now that I have watched the whole video I am looking forward to this topic in the next one!

[@kerrykerry5778]

I live in Amish country in Lancaster, PA. Our shiny new DDI has horse and buggy lanes. Talk about ratcheting the complexity up a notch, lol.

[@joedance14]

When I first saw one of these, my initial reaction was shock and disbelief - which lasted all of perhaps two seconds. Then, it was “brilliant!”, and a whole bunch of questions. Great video! Thank-you.

[@BadDriversofMaryland]

So happy you're gonna be talking about peds and cyclists, appreciate it.

[@pleasedontwatchthese9593]

I hope they talk about though traffic coming off the high way / service road too. They have to make a left or right turn.

[@mcb187]

I have used a DDI as a pedestrian at Fillmore/25 in CO Springs. It is super intuitive. Even if you can’t see the signal, it is very obvious when you can go, and all the crossings are short. This is very different to the SPUI 1 mile over at Garden of the Gods/25. You need a very long time to cross the intersection, and it isn’t obvious where the cars are supposed to come from, especially left turning traffic from the cross street to the freeway.

[@HweolRidda]

Good to hear you are going to consider bicycles and pedestrians. As a pedestrian my total count of conflict points was higher than yours.

[@paulwoodman5131]

Also... which way do you look at each point, are you SURE? walk through them a few times and you'll learn.

[@PrograError]

I wonder ain't it better to just link all the ped and cyclist traffic down the middle, just remember to make the paths double wider than it would have on a normal sidewalk.

[@alhutchison447]

We've started this in Arizona may be shortly before/ after this video. The new South Mountain Loop 202 has two HALF DDI. Half because the streets end at the southside of the freeway so traffic must enter the freeway after going under the bridge. ADOT is currently seeking input about converting the existing standard diamond interchange at I-10 and Baseline Road (just south of the US-60 Superstition Freeway Interchange). That area is very busy and seems to be a favorite project for ADOT to rebuild every 10-years. They are already doing so again now. A major rework of I-10 from the Loop 202 Santan (east)/South Mountain (West) interchange past Baseline and the US 60 Interchange, rebuilding/redesigning the SR-143/I-10 Interchange (SR 143 provides access to/from the east side of Sky Harbor Airport) out to the eastern interchange with I-17.

[@jonesyokc]

While it looks pretty on paper, anytime you get drivers switching the side of the road they are driving on, you increase the odds of human error. Efficiency designs can be problematic in real world applications. I cannot count the number of times I've seen people fail to properly handle a roundabout.

[@Normal1855]

Exactly. The severity of accidents are going to be higher.

[@featherpony]

9:31 the problem with this left on red after stop is that the red left arrow is SOLID. It SHOULD be a BLINKING red arrow, which is like a left turn stop sign (stop and yield).

[@Finn-sm3jf]

The problem with that is flashing red arrows can’t be displayed unless the directions crossing it perpendicularly are red. In this case a flashing red arrow would not be allowed. The sign changes the meaning of the red light and allows the turn on red after stopping.

[@featherpony]

@@Finn-sm3jf Why would the perpendicular lights need to be red? You can have a flashing red left arrow (aka stop-and-yield stop-sign left arrow) even with green perpendicular lights. Blinking red (also stop signs) do not mean stop-and-go. They mean stop-an-yield. Yield means you can't go until there is a safe break in traffic. So the perpendicular road can have green lights. Because the person at the blinking red arrow has to sit there and wait on all the green lit traffic, which may take a long time. Haven't you ever seen a stop sign at a roadway with no lights (equivalent green)? The person at the stop sign has to wait for an opportunity to turn. Just like when you leave a driveway.

[@Finn-sm3jf]

@@featherpony Because it’s a mutcd requirement. If a traffic signal is operating in steady (stop and go) mode, flashing left turn arrows shall not be displayed unless it is allowing a permissive left turn across oncoming traffic or a crosswalk. Since there is no oncoming through movement or crosswalk, a flashing red arrow cannot be displayed in the steady (stop and go) mode because it could be mistaken for a signal that is in flashing (malfunction) mode. Flashing red displays at stop signs are allowed since the the intersection is not controlled by traffic signals, it is controlled by flashing beacons.

[@jamesquaine6264]

He went to france and never noticed the roundabouts?

[@filipBuj]

Thank you so much for this amazing content. Will definitely try to drive thru this interchange the next time I’m in SLC

[@Arlae_Nova]

Ohno, left turn on red? Pls no. Pedestrians and cyclists cry just thinking about it.

[@RealestUrbanism]

eh. as long as the turn on red *after* stop is enforced, I'm ok with it. 4 way stops are pretty safe for pedestrians

[@nickallain]

I watched this video 3 months ago when it came out and today, I got off the highway in Overland Park, MS... I recognized the diverging diamond instantly and got WAY more excited than probably anyone who has driven through it

[@JDMatthias]

For 4-8 lane traffic, this works really well. I still prefer roundabouts for 2 lane traffic

[@traffic.engineer]

As do many American DOTs.

[@photoniccannon2117]

One of the best videos I’ve ever seen on these kinda of topics. Bravo, well done.

[@kylorenkardashian79]

Love your content Rob. you're a modern day Huell Howser ❤️

[@nickfifteen]

RIP in peace, Huell ;_;7

[@timothyosborn1697]

This DDI is in my hometown of American Fork and is awesome! It has done so much to alleviate traffic snarls entering, and leaving the freeway. I fully support them!

[@Kerleem]

Great video! Hopefully you’ll do one about bringing roundabouts to North America as well!

[@traffic.engineer]

America has been building roundabouts everywhere for the last 3 decades. They are relatively commonplace.

[@C.I...]

I'd like to see a comparison between this and big roundabouts/dog bone roundabouts.

[@ladasodaexplains3355]

Thanks to channels like this, I was not surprised when I drove through one for the first time 2 weeks ago

[@qo92]

Would be interested to see a SPUI/DDI vs Roundabout comparison.

[@SnarlyCharly]

There's an interchange on my way to work that has been turned into a DDI, complete with brand new bridges. When you see one for the very first time, I can admit it's a bit out of the ordinary compared to what we're used to in America. But there are so many signs and arrows everywhere, telling drivers exactly what to do and where to go, as long as you pay attention to the signage there's no way you can mess up. It's weird the first time through for sure, but once you know how it goes, you know.

[@MarkReviews]

“That’s a deal-breaker, ladies!” - 30 Rock

[@TaxationIsTheft69]

I love these and they should be up everywhere they can. Passed through one in Farmington Missouri and my life was changed forever.

[@effiejames9129]

I’m learning about DDIs now that Nashville is building one. Can you do a video on how multi lane roundabouts work? Single lane ones are ok, but two or more lanes spell trouble.

[@RusNad]

Outer lane for right turns and going straight, inner lane for turning left (past 12 o'clock). Move to the outer lane at the penultimate exit (any car in that lane should be taking that exit, quick check in the mirror to confirm that). If there are more than two lanes, generally you should move one lane over to the outside after every exit. Usually there will be lane markings to indicate which lane to be in for your exit.

[@effiejames9129]

@@RusNad I need video! LOL!

[@RusNad]

@@effiejames9129 Haha I get it. They're pretty rare in the US but in Europe they're absolutely everywhere. We've got something in the Netherlands that's called a turbo roundabout which automatically guides the inner lane into the outer lane and separates the right-only lanes with raised bumps, and I think it's a lot safer than a normal two-lane roundabout.

[@MrPeanut656565]

@@RusNad Yeah, turbo roundabouts are amazing. The first time I saw them (I am from Spain) I was like "WTF is this shit, makes no sense". Then I saw a picture of them from the air and instantly understood everything. Whoever invented them is a genious!

[@ArtiePenguin1]

Great video, very informative. I'm looking forward to your continuation video and expansion on bicycle/pedestrian crossings. At 9:02, I thought you said "From American Pork Main Street" at first. LOL. Thankfully you create all the captions for this video. Also thanks for not running ads in these videos, I really appreciate it!

[@76carmel]

The worst time to drive a diverging diamond is at night.

[@jacobg.witmer]

I’m from Toledo Ohio. We got a diverging diamond interchange a few years ago in Perrysburg, Ohio. It’s at the interchange from I-475/US-23 to OH-25. We also got a single point urban interchange from I-475/US-23 to Central Ave (US-20/OH-120).

[@falloutpictures]

Awesome video, I've crossed both DDI's up in Utah and realized how good it was the first time I crossed it. My hometown in Florida was the fourth one in the state that just recently opened in the last couple of months with several under construction. People fought it, now that it is open, people love it. The traffic is still pretty light for the DDI but for once FDOT planned ahead.

[@Outlaw_1320]

These intersections are always so interesting

[@scottgrohs5940]

What I’m wondering is how to resolve the DDI back into standard street traffic without a traffic light, because if you have a traffic light then all you’ve done is advance the location of the bottleneck for exiting freeway traffic…🤔

[@sjokomelk]

I am a bit confused about the whole DDI thing. Why build something that needs traffic lights? Most places in Europe use a roundabout on both sides of the bridge instead of traffic lights. There are even less conflict points, and you can have fairly uninterupted flow in all directions at all times.

[@traffic.engineer]

Roundabouts have an upper threshhold of volume where it no longer efficient. Yes, America does use roundabouts at interchanges, but finds better performance at low-mid range volumes.

[@mch2359]

There is a major issue with these intersections. The dependence upon traffic lights, and the impossibility of properly timing the traffic lights. Wait at the end of the ramp and wait for a full cycle of the lights then enter the intersection and wait for another full cycle while waiting for the cross traffic. Odds are when released from that light, the next light out of time. These intersections were just installed on I-75 intersections in Troy Michigan. The lights are totally out of time with the other lights in the area, unlimited budgets and untimed lights.

[@goldenegg7447]

I love your enthusiasm for roads and transportation. I couldn't find anyone else who makes me this interested in roads.

[@sammymarrco2]

13:10 such a deadly bike "lane"

[@highnoon9333]

When they built the first one in Atlanta (well, Dunwoody, GA, to be exact), it was huge news and everyone was angry. Once they realized that it actually works, and works well, people were so happy. Everyone always complains about driving in Atlanta, but the Ashford-Dunwoody/285 interchange in Dunwoody is just a pleasure to use.