Reality: Engineers use roundabouts because they're a fairly safe junction Yumbl: Drive in to the 5 lane roundabout at full speed without stopping, it'll be fine.
Roundabouts are also pretty good for traffic as long as both roads have similar traffic and enough people are turning. If there's lots of through traffic then they're not efficient in terms of how big they need to be.
19:50 and that folks is why in the UK they eventually upgrade previously working roundabouts on reasonably quite roads to become traffic circles with traffic lights on now busier roads 😀
For the lighted roundabout, you can actually go one further: The lights are forbidding the right-hand slip since the game thinks it's the same movement as the general right-hand turn onto the main roundabout. But, if you add a separated slip lane as an actual separated road on a different node, it can be controlled independently and made to always flow. Also, you can fork the approach roads to improve your entry/exit angles.
A dedicated slip lane only helps that particular traffic though, it has no effect on any of the other traffic flow of the intersection. But yes, it can help if you have extra heavy flow on right-turn traffic. You could even do it for just one side of the roundabout where it's needed. I do agree on forking (splitting) the junctions, while increasing the junction sizes like he did does make for smoother turns and better flow it also moves the stop line back, which makes it take longer for traffic to enter. It can make managing traffic and lights a bit funky, since you're essentially going from 4 to 8 (12) junctions, but it shouldn't be too much of an issue. Both your suggestions do increase the size of the roundabout and size constraint is often the reason a roundabout is used over a different interchange.
In real life an 80 meter roundabout is quite normal. In my town in the Netherlands we have a roundabout of 90 meters, and one of 85 meters. A city further away has a 200 meter roundabout, or actually, since it has traffic lights it would be considered a traffic circle.
I agree, in the UK I wouldn't say this is unusual. Where I live in stockport, there are two roundabouts that are about 150m in diameter within a mile of each other. I can think of one at old trafford too thats way over 100m and about 5 lanes wide at one point.
I think YUMBLE's point was that in CS, the 80m roundabout is a pretty standard to use anywhere (mostly because closeness of nodes causes problems), but in reality it isn't. I'm sure your 80+ meter roundabouts are on larger, high density roads, yes? You wouldn't find something like that in a quite neighborhood, right?
Had to check my home city, most roundabouts are about 50 m, give or take 10 m (doing a quick look up in Google maps isn't that accurate). Some are smaller, and a few are 100 m or larger.
Hi Yumble, do you ever seen the “Rond-point de l’Étoile” in Paris. This is a gigantic roundabout around the Arc de Triomphe. There are no lanes and you have “normally” to give wait to the incoming traffic.
Yeah, that's one of the most infamous roundabouts in the world. My sister's lived in France for 25 years outside of Paris and she didn't dare try that thing until she had lived there for more than five. The Rond-point de l’Étoile is basically France's full contact sport. You could do it with the blank roads collection in Cities, too!
If you mesure it by size, there's between 10 and 12 lanes on there, plus there's 12 street coming in the roundabout (and they are not small streets, they are typically 2+2 and can go up to 4+4 )
@@Mythriak_ Tried it and it worked pretty well as long as u have a massive roundabout (at least 120 - 150m with precision engineering) with at least 6 lanes and u use the lane connector to make sure that they can exit from more than 2 lanes (I did it with approximately 4). This only makes sense with more than 6 exits though.
@@Tyranastrasza A french colleague took we there in the car. His remark: just drive forward, except there is a taxi comming from the left. Then yield to the taxi.
The fact that yumble managed to take such a medium traffic setup and make it into a traffic black hole is insane to me. He is proving us every time that he is one of THE greatest traffic solvers of all times in the Cities: SkyLines community!
I found that allowing traffic to enter blocked junctions, especially for smaller roundabouts, really helps the traffic flow. I believe it is because of the way the game dictates what a junction is and when it is considered blocked. In the game when it is not allowed, each vehicle has to wait until the junction is completely empty before it will enter, but when it is allowed, each vehicle just waits for adequate space for it to enter. It would work better if the yield worked more like a yield than a full on stop sign though. If there is any vehicle in between 2 nodes, that whole section can be considered occupied so the entering traffic stops.
You should allow the intersection clockwise into the roundabout to wait in the roundabout for the cycle. They advance a bit to start and allow free flowing right turns during the previous cycle without creating any conflicts (except for rare U turn events, which I'm not sure this configuration allows).
I usually make a 1 second signal stage between each of the main stages to give the next direction a head start to make it around the first quarter of the roundabout. You get the same capacity boost that danbert87 describes, and you avoid having traffic stop twice.
Yay! Cities Skylines can’t cope with lanes that are multi-directional so you need the seven lanes. In real life you would be fine with four which were multipurpose. It was nice to see the traffic circle implemented. I’ve used it within my cities recently and as you discovered it can cope with a lot. Ps lovely to see you messing about before you got going 🤣
On the traffic circles, if you allowed the arm clockwise from the arm currently going to enter the circle and proceed to the first traffic light that would increase speed and capacity by some. Also, if you made two 3 way roundabouts, each handling two directions with one additional road connecting them that'd also be a way to get additional capacity.
I think you would need to color-code those roads in the 8-lane round about so people dont get lost in it. Also indicate where does it lead to and add normal round abouts further in each direction so people can actually go back the same way they came from.
I would love to see your take on the magic roundabout. You make such beautiful intersections with intersection marking tool and have a mastery of node controller and Lane connectors. It would be fascinating to see what you could make try to do it.
You could add an additional lane in the very inside where it goes closest to the center island for u-turns and because it's the inner most lane vs. the outer most for right turn traffic, they could still go as well.
Every time you said "leaving the realm of reality" I just had to laugh, as those 'unreal' roundabouts absolutely exist in Tijuana and I drive them regularly. Basically they are a complete free-for-all at all times, although there are some that are traffic signal controlled also.. Some are 3 lanes, some are 4 or even 5, but in reality people just go wherever the hell they want to.
@@renakunisaki Surprisingly few accidents here. Since everyone drives crazy all the time everyone is expecting the other guy to do crazy stuff and pays attention much better than I typically see in the US.
My first thought about the last round-about was that it could be 'juced' still more by just adding a node-seperated right turn only lane for every roading entering, so right turns never have to stop or even technically use the round-about.
I really think you've found your niche, Yumbl. Your intersections and roundabouts are a marvel of clever design, and a few of them have quietly been introduced into Storm City. They are indeed traffic black holes, and while Storm City doesn't have many cars (I'm trying HARD to move away from them since the book series' settings had none) it has a ton of local cargo trucks and needs all the help it can get. One of the monster roundabouts at the end WILL be making an appearance in SC, too. This sort of engineering insanity is *exactly* in character for the "builders" and it does indeed eat enough traffic to handle the central intersection of the city.
I feel like I'm on the M25. Though the limit on roundabouts is often 40mph, not that you can always get that speed with the cars in front, but if it's clear you can head on through.
Take a look at the Roundabout "Siegessäule" in Berlin "Straße des 17. Juni" it has dedicated right turn and the uncoming traffic from the roundabout beforehand junction is never supposed to merge with the right turn but actually has its own turning lane, but then you dont want to look at Paris or Rome with their Triumph Arches Roundabouts :D
My favorite use of roundabouts is for grade-separated highway junctions. Let the highways cross each other at different elevations, with uninterrupted straight through traffic, and then between them (in the vertical sense) place a roundabout for turning left/right, with entry/exit ramps.
I really appreciate all these compact intersection designs (these roundabouts, traffic light setups, vanilla overpass, the junctions on your last video) because you can upgrade to them as necessary with minimal rebuilding. Interchanges are nice but you generally want to build them in an empty spot, this stuff is highly practical because you can upgrade your busiest intersections without leveling a few blocks. And as a result this has allowed me at least to build with more freedom and not stressing over future traffic knowing I can handle whatever comes. Specifically for roundabouts I like the look but have avoided them so far because they have been disappointing in terms of traffic flow compared to lights, but with these upgrade options in mind I may have judged them too harshly!
Great video!! With the traffic roundabout, you can block the left turns and do only a 2 cycle light to increase the flow (north and south allowing the front and right traffic, and west and east allowing the front a right traffic)
22:20 in the seven lane it still can be optimized. when the car move, it only go to the left, straight & right. never go back (u turn) thus, the left lane of it, can do the right turn without disturbing the flow.
How about using asymmetrical roads to create a magic roundabout? It'll reduce a bit footprint of left turn traffic. I think with traffic lights it's pretty safe and doable.
imo the biggest benefit of a marked traffic circle is that it shows you where to go and you don't leave your lane, removing the risk of looking over your shoulder while going through a circle to see if it's safe to merge into a different lane
YUMBL, you should look at a similar solution in the city of Canberra, Australia (known to Australians everywhere as being full of roundabouts, like that’s a bad thing, and winner of international roundabout of the year in 2020). The roundabout at the intersection of Gubdaroo Drive and the Barton Highway is similar to the one here, but traffic turning right (left for you) actually stops on the roundabout - this allows traffic from opposing entrances to enter at the same time, where most of the traffic is through traffic.
You could have the traffic lights permitted to have green phases, with traffic lights on the roundabout lanes to make traffic wait, and so fill up the little gaps that are otherwise going unused, slightly reducing waiting times. We do this a lot in the UK's busier roundabouts, or have something like N-S green, E-W red, but it allows for more than four major roads to join. Lots of fun things can be done with combining roundabouts and traffic lights.
Hey Yumbl, after a long break, I've returned to your channel and enjoyed re-watching a lot of videos. What you've done at 20:15 with the lights-controlled roundabout, made me think of a real-life scenario, and maybe you wanted to check it out with safety in mind. At least, past the realm of CS1, with its non-lethal car-pedestrian accidents at every crosswalk - Coordinates: 51°22'01.7"N 6°10'00.4"E Edit: Imagine making the 8/7-lane roundabout (24:40) but you don't know that IMT exists. 💀
I actually like the "some people are not obeying the rules at times".. I know it can be frustrating when trying to get traffic just right, but I believe it adds to the realism, as people often don't obey the rules at times on the road.
Really fascinating and breath-taking, once again ... 12:11 These two lanes (the one with the connectors) are actually doing the same thing. And with four lanes (later more) going into the roundabout you go further down that path of multiple lanes with a similar/equal* function. *) Within the area of the roundabout experiment I'd say equal. But looking at the test map setup of 1:39 it might be smart to be either in the right or the left lane for the highway interchanges- and therefore to [12:11 again] travel the red or the blue lane connector. This is why the lanes are only similar but not equal - and this is actually part of why it is working. In reality there would be other intersections closer to the roundabout, and blue lane would attract people who turn left at the following junction, red lane those who turn right there ...
One thing you can do to improve the flow is adding short "overlapping" phases. So basically, the next phase can enter the roundabout just before the current one gets a red light. Example of green light phases: 1. North 10 seconds 2. East 10 sec 3. South 10 sec 4. West 10 sec Instead: 1. North 8 sec 2. N+E 2 sec 3. East 8 sec 4. E+S 2 sec 5. South 8 sec 6. S+W 2 sec 7. West 8 sec 8. W+N 2 sec This makes the entire cycle take the same amount of time but each phase gets 2 extra seconds. It may take some fiddling to get the timing just right, but it allows the vehicles of the next phase to start entering the part of the roundabout that is clear of traffic anyway. Maybe there is a more elegant way of doing this, i don't know, but this is also how most traffic lights work in the Netherlands, the lights turn green before the other direction's turn red to compensate for the time it takes to enter the junction.
There's a roundabout near me which is about the same radius as this one (it's not perfectly circular, but it's comparable in size). It could theoretically be a T-junction of an arterial (one which desparately wants to be a highway) from which another arterial emerges, but it also joins to four collector roads of varying sizes. It has three lanes, traffic lights at some (but not all) of the junctions, and is absolutely horrible.
In NZ we have lots of light-controlled roundabouts that work almost like the final one, but with fewer lanes. I think it's a result of squeezing capacity out of our many existing roundabouts as they grew 10x busier
With that volume I would usually do a British roundabout interchange on the junction. No lights. The reason I opt for that setup is because it's scalable in the long run. The busier road gets a straight-through at ground level (the roundabout is above ground). When the intersecting road gets busy enough I put that into a tunnel straight-through. And then when the volume starts to overwhelm that setup, I put in slip lanes for left turns (left side driving). So at the very end, the roundabout becomes a right-turn only mechanism. Usually when the junction reaches this state, the traffic can sort itself out no matter what is thrown at it.
@@YUMBL The really busy interchanges usually evolve into what you have at the 7 minute mark. At which point, it's as good as it gets. The difference between my setup and what you have in your video, is I prefer the roundabout to be elevated. So when I need to scale up, by making the intersecting highway straight-through, I don't have to fiddle with the roundabout.
In Manta Ecuador there is a 4 lane round about but there are no lane markings or signs, its total chaos but it seems to work there. I remember being on a bus and taking a few laps around till the driver was able to escape. Good times. Great video man, keep it up.
In the last iteration, there are 8 lanes, by you are using 7. The inner lane has the buffer, if you shift all the outer lanes over one, then it frees up the outside line to be used exclusively for turning right. It essentially produces a bypass, so even with a traffic light, the outside lane would never have to wait.
26:28 When all our cars become self driven and sufficient in terms of safety without human intervention, these are the types of intersections I would expect to see lol
I think you made a mistake with the five lane roundabout, the two arrows from the previous roundabout section should be a lane up, to allow the furthest out lane exclusively for right turns from those entering the roundabout
The rediculous round about in the end of the video is actually pretty close to what we have here in the Netherlands since a few years. Take a second to get used to, but actually quite nice.
Great info, YUMBL! Love how the very last roundabout design fixes traffic UNBELIEVABLY WELL in that map you're using! Always love your videos! I don't particularly like roundabouts, but I always love your videos! I'm actually subscribed to your channel, so keep making Cities: Skylines videos like these!
Have you considered a magic roundabout like the ones in Swindon and Hemel Hempstead in England? Essentially, your roundabout has traffic going in both directions around it, and you have roundabouts at each of the entrances with three exits - two for going round the main roundabout in each direction, and one for the actual road that connects to it. In real life you get an insane amount of traffic flow with zero delay, though it is very scary to drive round if you are not used to it.
One suggestion for improving the traffic lights on the roundabout: I'd add 4 in-between phases where the new entrance direction gets green together with the old one. That phase should last for less than 4 seconds. (It takes a truck 12 seconds to go through 3 quadrants, thus 4 for one quadrant, and from that you'll want to subtract how long it takes the lights to change.) I would not allow for any elasticity in the time here. For the time of the remaining phase, you'll want it to stay close to the time needed for 2 quadrants, i.e. 8 seconds at this size and speed. Letting the traffic light deviate from that is fine; you'll just have an unused quadrant for any time above these 8 seconds, and an unused quadrant and more frequent phase changes for any time below the 8 seconds. I'd make this a 8...13 setting with this amount of traffic. Alternatively, you could use EXCLUSIVELY these two-entrances phases, which would allow traffic to stack up one node into the roundabout.
Honest question..... whats the point of the roundabout? If you remove the roundabout, keep the same roads, the cars travel less distance to do the same turns... the traffic lights only allow for one road at a time anyways.
I'm a roundabout fan but your simulations help me understand the limitations of roundabouts. After viewing this video, I'm curious how roundabouts and standard intersections compare when neither have traffic lights. For example, the turbo in this video performs poorly without traffic lights, but how would a standard intersection with the same amount of lanes perform without traffic lights? I don't have this game or any other game because I have to preserve my wrists for work. I cooked both a long time ago and I have to give them a rest. Would like to see a comparison for two lanes, three lanes, four lanes, and five lanes as well. Also, how would one design a city that cannot have traffic lights?
This video should be titled "what if the city of LA designed a roundabout?" Though, the final product looks very satsifying. I'm wondering if the devs thought it'd be possible when they first released CSL.
Beyond 3 lanes a roundabout is no longer really a suitable intersection. You can remove the right turn (on RHD roads) to its own lane to keep 3 lanes on the actual roundabout itself. But beyond that the Roundabout needs to be turned back to traffic lights with just crazy amounts of lanes. Or start to grade separate.
This is great! I would love to see how you built the last roundabout with the filled lanes. Or even better if you can create this an asset in the Steam workshop.
This is actually pretty good. Now I want to see the most overkill intersection for a city (not a roundabout) but seems like it wouldn't work but works way too much
In Germany a lot of big roundabouts have an extra lane for turning right. It allows you to skip the roundabout and give space for people who need to go straight or turn left. It's quite effective 😉
In the UK the traffic lights are set up as such, that they are stopping traffic on the rounabout too, i don't know what advantage it has, but if you put the lights at the entrances to the roundabout, then it is as you said it's a traffic circle, a bloated 4 way intersection.
This game might give a rough idea of flow but the behaviour isn't realistic at all. Every vehicle calculates the fastest path (assuming no traffic) and never deviates from it, and vehicles never collide or break down.
You should really upload these to the workshop. Your detail is insane and would be appreciated :) although you give such great detail sometimes they can be replicated nearly the same 😊
You could improve it further by allowing vehicles from the fourth road into the roundabout, since no cars from the first road travel further than the third exit (fourth road). That way you will use the whole roundabout instead of 3/4 of it. The cars from the fourth road who wants to go straight or turn left can wait at the next traffic light (it’s their turn to go at the next step of the cycle, so they won’t have to wait long) and the cars who want to turn right can exit straight away since that light is green for them anyway.
The cities skylines turbo one is like every roundabout in the UK haha. Also, I see a ton of roundabouts with traffic lights at each intersection so you have to stop while on the roundabout. I don't know if you've ever tried those in CS, but it oculd be interesting
They have a similar traffic light controlled roundabout in Graz, Austria (47°01'58"N 15°24'42"E) but instead of 5 lanes it has 4 and it has painted lines instead of raised curbs.
Now it's time to give it a REAL challenge: - turn off despawning - restrict the flow out of the roundabout on all 4 exits - wait until it is totally jammed up - remove the restrictions - see what happens. When I test my optimized cloverleaf like that, it recovers within minutes but the vanilla cloverleaf does not.
24:52 while I understand that the line separations look nice and all, considering you're only allowing one leg of traffic onto the roundabout at a time I don't see the point of giving only 1 lane for right and left turns. why not 3 + 3 + 3. they won't interfere with each other. Yes, if 'straight ahead' traffic is more likely, then sure... but if not then your 2 outer lanes will get way more backed up than the 3 middle 'straight through' lanes
I think there are 5 lane round about in Barcelona. There is one very scary round about in Tetuan that is regulated by traffic lights, but I believe it is 5 or over 6 lanes.
Arizona is covered in roundabouts. The Arizona DOT even produces a guide for people on how to use roundabouts. I live in a small town and within 2 miles of my house there are 5 roundabouts.
You've mastered the Turbo roundabout! I think it would be cool if you did an interview with it's inventor Bertus Fortuijn and discuss advantages and disadvantages of roundabouts in real life and how they translate into the game.
I don't think it ever would have occurred to me to flatten a turbine interchange, but that seems to be what has happened here. I'm gonna have to try this.
With the traffic lights you can speed it up slightly by allowing traffic to enter the roundabout one step earlier, and having them wait on the traffic circle. Right now a quarter of the roundabout is empty at all times.
I think this is a logistical nightmare in real life, the more rules and complications you present to system, the more accidents and hiccups there is. What if i miss my turn? in roundabouts i can easily go for another spin but in this system i cant, I run the risk of beating the next redlight or I can and run the risk of colliding with the incoming traffic
This traffic light roundabout has given me horror flashbacks to a nasty piece of modern engineering next to London Heathrow airport (M4 junction 4). It’s a bad roundabout in practice due to a large number of drivers entering in the wrong lane (the signage and lane markings are poor and contradicting to make matters worse). The designers of yesteryear didn’t have hindsight for things like this sadly.
Junction 4 + Cherry Lane Roundabout just to the north has got to be one of the most insane road junctions ever made. The bypassed roundabout is actually fully under motorway regulations too since the M4 spurs to the south and a little bit north to the Cherry Lane Roundabout (which is a hamburger/throughabout because of the straight connector from the M4 to the 408). There is also the interesting scenario that traffic can actually enter the straight through section which leads to the motorway regulations but with no legal escape (since the road through the roundabout bans all turns), which is why there are signs warning of the motorway 75 yards ahead. Cherry Lane Roundabout used to be a 'hot cross bun' which is literally a roundabout with a crossroads within it, as can be seen if you go back in time on google street view.
7:52 this is the moment you start making turbo roundabouts. What makes a roundabout turbo is the shifting lanes. You never have to weave and the inner circle never has to yield to an outer circle. I don't think real real multi-lane roundabouts allow for that, yet your 2-lane straight priority roundabout does.
There is a huge traffic circle type situation in Dubai. It's called the Trade Centre Roundabout. I believe 8 points of entry. Huge traffic circle. 4 lanes. You can have a fun time looking at that situation if you like. Works ok, for the traffic it gets hurt with.
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Reality: Engineers use roundabouts because they're a fairly safe junction
Yumbl: Drive in to the 5 lane roundabout at full speed without stopping, it'll be fine.
Roundabouts are also pretty good for traffic as long as both roads have similar traffic and enough people are turning. If there's lots of through traffic then they're not efficient in terms of how big they need to be.
19:50 and that folks is why in the UK they eventually upgrade previously working roundabouts on reasonably quite roads to become traffic circles with traffic lights on now busier roads 😀
Oh yes. The initial designs are quite plausible. Even 4+ lanes with lights! Then we leave reality entirely 😅
And then we also have traffic circles on motorway junctions when a stack interchange would be better, because apparently cheaper is better!
@@ThatRandomBeast Yeah, stack interchanges are much better system interchanges than three-level roundabout interchanges.
the really good thing is it's safer because you're avoiding left turns!
*Tea sipping intensifies*
For the lighted roundabout, you can actually go one further: The lights are forbidding the right-hand slip since the game thinks it's the same movement as the general right-hand turn onto the main roundabout. But, if you add a separated slip lane as an actual separated road on a different node, it can be controlled independently and made to always flow. Also, you can fork the approach roads to improve your entry/exit angles.
A dedicated slip lane only helps that particular traffic though, it has no effect on any of the other traffic flow of the intersection.
But yes, it can help if you have extra heavy flow on right-turn traffic. You could even do it for just one side of the roundabout where it's needed.
I do agree on forking (splitting) the junctions, while increasing the junction sizes like he did does make for smoother turns and better flow it also moves the stop line back, which makes it take longer for traffic to enter. It can make managing traffic and lights a bit funky, since you're essentially going from 4 to 8 (12) junctions, but it shouldn't be too much of an issue.
Both your suggestions do increase the size of the roundabout and size constraint is often the reason a roundabout is used over a different interchange.
In real life an 80 meter roundabout is quite normal. In my town in the Netherlands we have a roundabout of 90 meters, and one of 85 meters. A city further away has a 200 meter roundabout, or actually, since it has traffic lights it would be considered a traffic circle.
Within the realm of normal, yes, but it has to be larger than the average roundabout.
I agree, in the UK I wouldn't say this is unusual. Where I live in stockport, there are two roundabouts that are about 150m in diameter within a mile of each other. I can think of one at old trafford too thats way over 100m and about 5 lanes wide at one point.
I think YUMBLE's point was that in CS, the 80m roundabout is a pretty standard to use anywhere (mostly because closeness of nodes causes problems), but in reality it isn't. I'm sure your 80+ meter roundabouts are on larger, high density roads, yes? You wouldn't find something like that in a quite neighborhood, right?
Had to check my home city, most roundabouts are about 50 m, give or take 10 m (doing a quick look up in Google maps isn't that accurate). Some are smaller, and a few are 100 m or larger.
In São Paulo has a 225m 4 lane roundabout
-23.514295766880483, -46.62945962736576
it's nice to see that yumble is actually having fun with his new camera😅
Its a few years old. I’ve been streaming for a long time :)
@@YUMBL Welp...🤐
But it's still new for us!
he looks like a psycopath tho
but a nice one 🥲
Hi Yumble, do you ever seen the “Rond-point de l’Étoile” in Paris. This is a gigantic roundabout around the Arc de Triomphe. There are no lanes and you have “normally” to give wait to the incoming traffic.
This would be something amazing to try to represent in Cities Skylines. Specially if Yumble try to do it.
Yeah, that's one of the most infamous roundabouts in the world. My sister's lived in France for 25 years outside of Paris and she didn't dare try that thing until she had lived there for more than five. The Rond-point de l’Étoile is basically France's full contact sport.
You could do it with the blank roads collection in Cities, too!
If you mesure it by size, there's between 10 and 12 lanes on there, plus there's 12 street coming in the roundabout (and they are not small streets, they are typically 2+2 and can go up to 4+4 )
@@Mythriak_ Tried it and it worked pretty well as long as u have a massive roundabout (at least 120 - 150m with precision engineering) with at least 6 lanes and u use the lane connector to make sure that they can exit from more than 2 lanes (I did it with approximately 4). This only makes sense with more than 6 exits though.
@@Tyranastrasza A french colleague took we there in the car. His remark: just drive forward, except there is a taxi comming from the left. Then yield to the taxi.
The fact that yumble managed to take such a medium traffic setup and make it into a traffic black hole is insane to me.
He is proving us every time that he is one of THE greatest traffic solvers of all times in the Cities: SkyLines community!
These types of roundabouts aren’t that crazy. The roundabouts at 55.868502,-4.367730 formed part of my driving test.
You sank my battleship!
@@paulchilders9969 what was your battleship doing in a roundabout
This channel is changing my perception of roundabouts. Traffic lights are not that bad after all
I found that allowing traffic to enter blocked junctions, especially for smaller roundabouts, really helps the traffic flow. I believe it is because of the way the game dictates what a junction is and when it is considered blocked. In the game when it is not allowed, each vehicle has to wait until the junction is completely empty before it will enter, but when it is allowed, each vehicle just waits for adequate space for it to enter. It would work better if the yield worked more like a yield than a full on stop sign though. If there is any vehicle in between 2 nodes, that whole section can be considered occupied so the entering traffic stops.
Speaking about realism, you should see the Arc de Triomphe roundabout. That is insane!
The problem with all the roundabouts is that theres never an option to go back on yourself or go around it again in case you're in the wrong lane.
Thankfully, though. The AI doesn't make "mistakes" so a u-turn isn't really necessary
Only turbo ones not all ones
You should allow the intersection clockwise into the roundabout to wait in the roundabout for the cycle. They advance a bit to start and allow free flowing right turns during the previous cycle without creating any conflicts (except for rare U turn events, which I'm not sure this configuration allows).
I saw this too, since you can't u-turn there's an entire quarter of the roundabout unused on every cycle.
I usually make a 1 second signal stage between each of the main stages to give the next direction a head start to make it around the first quarter of the roundabout. You get the same capacity boost that danbert87 describes, and you avoid having traffic stop twice.
@@OntarioTrafficMan Didn't you say something about Toronto's red clearance times that can be shorter without reducing safety?
@@5blocksmc979 Yes. In this case the 1 second signal phase represents the "entry time" of the next movement
Yay! Cities Skylines can’t cope with lanes that are multi-directional so you need the seven lanes. In real life you would be fine with four which were multipurpose. It was nice to see the traffic circle implemented. I’ve used it within my cities recently and as you discovered it can cope with a lot.
Ps lovely to see you messing about before you got going 🤣
On the traffic circles, if you allowed the arm clockwise from the arm currently going to enter the circle and proceed to the first traffic light that would increase speed and capacity by some.
Also, if you made two 3 way roundabouts, each handling two directions with one additional road connecting them that'd also be a way to get additional capacity.
I think you would need to color-code those roads in the 8-lane round about so people dont get lost in it. Also indicate where does it lead to and add normal round abouts further in each direction so people can actually go back the same way they came from.
I would love to see your take on the magic roundabout. You make such beautiful intersections with intersection marking tool and have a mastery of node controller and Lane connectors. It would be fascinating to see what you could make try to do it.
You can further optimize it by allowing right turn all the time. This is acceptable since U-turn is not allowed in your roundabout.
You could add an additional lane in the very inside where it goes closest to the center island for u-turns and because it's the inner most lane vs. the outer most for right turn traffic, they could still go as well.
I applied these lights to my busy roundabout and it's now, as you say, "eating traffic." I wonder what Biffa will make of this.
In one of his city fixes he took one look at the 5 lane, and immediately deleted it lol
Every time you said "leaving the realm of reality" I just had to laugh, as those 'unreal' roundabouts absolutely exist in Tijuana and I drive them regularly. Basically they are a complete free-for-all at all times, although there are some that are traffic signal controlled also.. Some are 3 lanes, some are 4 or even 5, but in reality people just go wherever the hell they want to.
I bet there are a lot of collision repair centres nearby?
@@renakunisaki Surprisingly few accidents here. Since everyone drives crazy all the time everyone is expecting the other guy to do crazy stuff and pays attention much better than I typically see in the US.
My first thought about the last round-about was that it could be 'juced' still more by just adding a node-seperated right turn only lane for every roading entering, so right turns never have to stop or even technically use the round-about.
I really think you've found your niche, Yumbl. Your intersections and roundabouts are a marvel of clever design, and a few of them have quietly been introduced into Storm City. They are indeed traffic black holes, and while Storm City doesn't have many cars (I'm trying HARD to move away from them since the book series' settings had none) it has a ton of local cargo trucks and needs all the help it can get.
One of the monster roundabouts at the end WILL be making an appearance in SC, too. This sort of engineering insanity is *exactly* in character for the "builders" and it does indeed eat enough traffic to handle the central intersection of the city.
I feel like I'm on the M25.
Though the limit on roundabouts is often 40mph, not that you can always get that speed with the cars in front, but if it's clear you can head on through.
Can't wait for Biffa to weigh in... 😈😆
This roundabout has saved my new city. Went from 70% traffic flow to 84%. Thanks much!
Awesome :)
CPP really needs a refresher course from you on round-abouts lol and great seeing your face (Applause) Another great vid
1:19 Now that's what I'm talking about.
I wonder what Clark Griswold would think about this roundabout.
I've had skylines for about 6-7 years and never have I wanted to play it more than when I'm watching your channel.
That roundabout gives me nightmares. Five lane roundabouts are unsafe, meanwhile the Eiffel Tower is a traffic pain in the ass
Take a look at the Roundabout "Siegessäule" in Berlin "Straße des 17. Juni" it has dedicated right turn and the uncoming traffic from the roundabout beforehand junction is never supposed to merge with the right turn but actually has its own turning lane,
but then you dont want to look at Paris or Rome with their Triumph Arches Roundabouts :D
My favorite use of roundabouts is for grade-separated highway junctions. Let the highways cross each other at different elevations, with uninterrupted straight through traffic, and then between them (in the vertical sense) place a roundabout for turning left/right, with entry/exit ramps.
I really appreciate all these compact intersection designs (these roundabouts, traffic light setups, vanilla overpass, the junctions on your last video) because you can upgrade to them as necessary with minimal rebuilding. Interchanges are nice but you generally want to build them in an empty spot, this stuff is highly practical because you can upgrade your busiest intersections without leveling a few blocks. And as a result this has allowed me at least to build with more freedom and not stressing over future traffic knowing I can handle whatever comes.
Specifically for roundabouts I like the look but have avoided them so far because they have been disappointing in terms of traffic flow compared to lights, but with these upgrade options in mind I may have judged them too harshly!
Great video!! With the traffic roundabout, you can block the left turns and do only a 2 cycle light to increase the flow (north and south allowing the front and right traffic, and west and east allowing the front a right traffic)
You can try, but the lefts overwhelm the roundabout. It would need to be huge
The traffic light pattern is very similar to what Wisconsin DOT puts on standard diamond interchanges between roads and highways.
22:20 in the seven lane
it still can be optimized.
when the car move,
it only go to the left, straight & right. never go back (u turn)
thus, the left lane of it, can do the right turn without disturbing the flow.
The right lane can’t be controlled separately from the others.
How about using asymmetrical roads to create a magic roundabout? It'll reduce a bit footprint of left turn traffic.
I think with traffic lights it's pretty safe and doable.
imo the biggest benefit of a marked traffic circle is that it shows you where to go and you don't leave your lane, removing the risk of looking over your shoulder while going through a circle to see if it's safe to merge into a different lane
Traffic light roundabouts are very common in Spain and they work good. They are just much bigger radius and usually 5-6 lanes
I click on these videos faster than Yumbl forgets about pipes and powerlines!
YUMBL, you should look at a similar solution in the city of Canberra, Australia (known to Australians everywhere as being full of roundabouts, like that’s a bad thing, and winner of international roundabout of the year in 2020). The roundabout at the intersection of Gubdaroo Drive and the Barton Highway is similar to the one here, but traffic turning right (left for you) actually stops on the roundabout - this allows traffic from opposing entrances to enter at the same time, where most of the traffic is through traffic.
If you've ever seen some intersections in foreign countries its really not unrealistic for this to be tried somewhere. Great video!
The end was so satisfying! i love seeing the traffic flow idk if that's just me 😅
You could have the traffic lights permitted to have green phases, with traffic lights on the roundabout lanes to make traffic wait, and so fill up the little gaps that are otherwise going unused, slightly reducing waiting times.
We do this a lot in the UK's busier roundabouts, or have something like N-S green, E-W red, but it allows for more than four major roads to join.
Lots of fun things can be done with combining roundabouts and traffic lights.
I did have it set up that way but it caused issues. I forget exactly why, but tmpe didnt like it.
Hey Yumbl, after a long break, I've returned to your channel and enjoyed re-watching a lot of videos.
What you've done at 20:15 with the lights-controlled roundabout, made me think of a real-life scenario, and maybe you wanted to check it out with safety in mind. At least, past the realm of CS1, with its non-lethal car-pedestrian accidents at every crosswalk
- Coordinates: 51°22'01.7"N 6°10'00.4"E
Edit: Imagine making the 8/7-lane roundabout (24:40) but you don't know that IMT exists. 💀
I love the light controlled intersection pretending to be a roundabout
I said it’s a traffic circle. No pretending.
I actually like the "some people are not obeying the rules at times".. I know it can be frustrating when trying to get traffic just right, but I believe it adds to the realism, as people often don't obey the rules at times on the road.
Really fascinating and breath-taking, once again ...
12:11 These two lanes (the one with the connectors) are actually doing the same thing. And with four lanes (later more) going into the roundabout you go further down that path of multiple lanes with a similar/equal* function.
*) Within the area of the roundabout experiment I'd say equal. But looking at the test map setup of 1:39 it might be smart to be either in the right or the left lane for the highway interchanges- and therefore to [12:11 again] travel the red or the blue lane connector. This is why the lanes are only similar but not equal - and this is actually part of why it is working. In reality there would be other intersections closer to the roundabout, and blue lane would attract people who turn left at the following junction, red lane those who turn right there ...
One thing you can do to improve the flow is adding short "overlapping" phases.
So basically, the next phase can enter the roundabout just before the current one gets a red light.
Example of green light phases:
1. North 10 seconds
2. East 10 sec
3. South 10 sec
4. West 10 sec
Instead:
1. North 8 sec
2. N+E 2 sec
3. East 8 sec
4. E+S 2 sec
5. South 8 sec
6. S+W 2 sec
7. West 8 sec
8. W+N 2 sec
This makes the entire cycle take the same amount of time but each phase gets 2 extra seconds.
It may take some fiddling to get the timing just right, but it allows the vehicles of the next phase to start entering the part of the roundabout that is clear of traffic anyway.
Maybe there is a more elegant way of doing this, i don't know, but this is also how most traffic lights work in the Netherlands, the lights turn green before the other direction's turn red to compensate for the time it takes to enter the junction.
There's a roundabout near me which is about the same radius as this one (it's not perfectly circular, but it's comparable in size). It could theoretically be a T-junction of an arterial (one which desparately wants to be a highway) from which another arterial emerges, but it also joins to four collector roads of varying sizes. It has three lanes, traffic lights at some (but not all) of the junctions, and is absolutely horrible.
In NZ we have lots of light-controlled roundabouts that work almost like the final one, but with fewer lanes.
I think it's a result of squeezing capacity out of our many existing roundabouts as they grew 10x busier
With that volume I would usually do a British roundabout interchange on the junction. No lights. The reason I opt for that setup is because it's scalable in the long run. The busier road gets a straight-through at ground level (the roundabout is above ground). When the intersecting road gets busy enough I put that into a tunnel straight-through. And then when the volume starts to overwhelm that setup, I put in slip lanes for left turns (left side driving). So at the very end, the roundabout becomes a right-turn only mechanism. Usually when the junction reaches this state, the traffic can sort itself out no matter what is thrown at it.
My experience with bypass roundabouts has not been so good in CS: ruclips.net/video/3dDHJZ1AWVY/видео.html
@@YUMBL The really busy interchanges usually evolve into what you have at the 7 minute mark. At which point, it's as good as it gets. The difference between my setup and what you have in your video, is I prefer the roundabout to be elevated. So when I need to scale up, by making the intersecting highway straight-through, I don't have to fiddle with the roundabout.
In Manta Ecuador there is a 4 lane round about but there are no lane markings or signs, its total chaos but it seems to work there. I remember being on a bus and taking a few laps around till the driver was able to escape. Good times. Great video man, keep it up.
In the last iteration, there are 8 lanes, by you are using 7. The inner lane has the buffer, if you shift all the outer lanes over one, then it frees up the outside line to be used exclusively for turning right. It essentially produces a bypass, so even with a traffic light, the outside lane would never have to wait.
The traffic light is all or nothing. The right lane can’t be controlled independently.
26:28 When all our cars become self driven and sufficient in terms of safety without human intervention, these are the types of intersections I would expect to see lol
I think you made a mistake with the five lane roundabout, the two arrows from the previous roundabout section should be a lane up, to allow the furthest out lane exclusively for right turns from those entering the roundabout
As soon as you are two lanes or more the first lane should be used as a slip lane in my opinion. Gives the roundabout a little better throughpout.
Nice to put a face with the voice. You Biffa and imperatur are my faves.
The rediculous round about in the end of the video is actually pretty close to what we have here in the Netherlands since a few years. Take a second to get used to, but actually quite nice.
Great info, YUMBL! Love how the very last roundabout design fixes traffic UNBELIEVABLY WELL in that map you're using! Always love your videos! I don't particularly like roundabouts, but I always love your videos! I'm actually subscribed to your channel, so keep making Cities: Skylines videos like these!
omg. that opening cut of the roundabouts is so beautiful
All I can think listening to this is that Yumbl is the Bob Ross of Roundabouts
Have you considered a magic roundabout like the ones in Swindon and Hemel Hempstead in England?
Essentially, your roundabout has traffic going in both directions around it, and you have roundabouts at each of the entrances with three exits - two for going round the main roundabout in each direction, and one for the actual road that connects to it.
In real life you get an insane amount of traffic flow with zero delay, though it is very scary to drive round if you are not used to it.
One suggestion for improving the traffic lights on the roundabout:
I'd add 4 in-between phases where the new entrance direction gets green together with the old one. That phase should last for less than 4 seconds. (It takes a truck 12 seconds to go through 3 quadrants, thus 4 for one quadrant, and from that you'll want to subtract how long it takes the lights to change.) I would not allow for any elasticity in the time here.
For the time of the remaining phase, you'll want it to stay close to the time needed for 2 quadrants, i.e. 8 seconds at this size and speed. Letting the traffic light deviate from that is fine; you'll just have an unused quadrant for any time above these 8 seconds, and an unused quadrant and more frequent phase changes for any time below the 8 seconds. I'd make this a 8...13 setting with this amount of traffic.
Alternatively, you could use EXCLUSIVELY these two-entrances phases, which would allow traffic to stack up one node into the roundabout.
Honest question..... whats the point of the roundabout?
If you remove the roundabout, keep the same roads, the cars travel less distance to do the same turns... the traffic lights only allow for one road at a time anyways.
That round-a-bout is both beautiful and positively terrifying.
I could watch that thing eat traffic all day! Guess I know what I'll be doing this evening...
I'm a roundabout fan but your simulations help me understand the limitations of roundabouts. After viewing this video, I'm curious how roundabouts and standard intersections compare when neither have traffic lights. For example, the turbo in this video performs poorly without traffic lights, but how would a standard intersection with the same amount of lanes perform without traffic lights? I don't have this game or any other game because I have to preserve my wrists for work. I cooked both a long time ago and I have to give them a rest. Would like to see a comparison for two lanes, three lanes, four lanes, and five lanes as well. Also, how would one design a city that cannot have traffic lights?
This video should be titled "what if the city of LA designed a roundabout?" Though, the final product looks very satsifying. I'm wondering if the devs thought it'd be possible when they first released CSL.
Beyond 3 lanes a roundabout is no longer really a suitable intersection. You can remove the right turn (on RHD roads) to its own lane to keep 3 lanes on the actual roundabout itself. But beyond that the Roundabout needs to be turned back to traffic lights with just crazy amounts of lanes. Or start to grade separate.
This is great! I would love to see how you built the last roundabout with the filled lanes. Or even better if you can create this an asset in the Steam workshop.
I think Yumbl needs to take a look at the magic roundabout in Swindon. He'd have fun trying to make that in Cities Skylines
This is actually pretty good.
Now I want to see the most overkill intersection for a city (not a roundabout) but seems like it wouldn't work but works way too much
Coming from Holland and seeying what this man did with his last roundabout...
Brilliant, just absolutely... brilliant 👌
In Germany a lot of big roundabouts have an extra lane for turning right. It allows you to skip the roundabout and give space for people who need to go straight or turn left. It's quite effective 😉
In the UK the traffic lights are set up as such, that they are stopping traffic on the rounabout too, i don't know what advantage it has, but if you put the lights at the entrances to the roundabout, then it is as you said it's a traffic circle, a bloated 4 way intersection.
I guess the advantage is that traffic can enter from multiple directions
Very interesting. I wonder if this could work as traffic simulation for city designer?
This game might give a rough idea of flow but the behaviour isn't realistic at all. Every vehicle calculates the fastest path (assuming no traffic) and never deviates from it, and vehicles never collide or break down.
@@renakunisaki ok, thanks
You should really upload these to the workshop. Your detail is insane and would be appreciated :) although you give such great detail sometimes they can be replicated nearly the same 😊
Reminds me a bit about the Verkeersplein Kooimeer infront of Alkmaar in the Netherlands. only with more lanes and higher traffic from some directions.
You could improve it further by allowing vehicles from the fourth road into the roundabout, since no cars from the first road travel further than the third exit (fourth road). That way you will use the whole roundabout instead of 3/4 of it. The cars from the fourth road who wants to go straight or turn left can wait at the next traffic light (it’s their turn to go at the next step of the cycle, so they won’t have to wait long) and the cars who want to turn right can exit straight away since that light is green for them anyway.
The cities skylines turbo one is like every roundabout in the UK haha.
Also, I see a ton of roundabouts with traffic lights at each intersection so you have to stop while on the roundabout. I don't know if you've ever tried those in CS, but it oculd be interesting
The 6 (5) lane roundabout with traffic light is sooo satisfying to see for my OCD 🥰
They have a similar traffic light controlled roundabout in Graz, Austria (47°01'58"N 15°24'42"E) but instead of 5 lanes it has 4 and it has painted lines instead of raised curbs.
Please make more content like this, the cities skylines fandom is so big!
Now it's time to give it a REAL challenge:
- turn off despawning
- restrict the flow out of the roundabout on all 4 exits
- wait until it is totally jammed up
- remove the restrictions
- see what happens.
When I test my optimized cloverleaf like that, it recovers within minutes but the vanilla cloverleaf does not.
24:52 while I understand that the line separations look nice and all, considering you're only allowing one leg of traffic onto the roundabout at a time I don't see the point of giving only 1 lane for right and left turns. why not 3 + 3 + 3. they won't interfere with each other.
Yes, if 'straight ahead' traffic is more likely, then sure... but if not then your 2 outer lanes will get way more backed up than the 3 middle 'straight through' lanes
Yumble: Mentions the word 'Roundabout'.
Biffa gets summoned. 😂
I think there are 5 lane round about in Barcelona. There is one very scary round about in Tetuan that is regulated by traffic lights, but I believe it is 5 or over 6 lanes.
I love these in real life, the Netherlands just knows how to do traffic infrastructure so well
Arizona is covered in roundabouts. The Arizona DOT even produces a guide for people on how to use roundabouts. I live in a small town and within 2 miles of my house there are 5 roundabouts.
You've mastered the Turbo roundabout! I think it would be cool if you did an interview with it's inventor Bertus Fortuijn and discuss advantages and disadvantages of roundabouts in real life and how they translate into the game.
Near Baltimore, MD there's a cool yet terrible roundabout in Towson. It's like a horrible oval. I love it.
I know towson! I’m just down the road in NOVA
I don't think it ever would have occurred to me to flatten a turbine interchange, but that seems to be what has happened here. I'm gonna have to try this.
With the traffic lights you can speed it up slightly by allowing traffic to enter the roundabout one step earlier, and having them wait on the traffic circle. Right now a quarter of the roundabout is empty at all times.
I wish it worked well. They frequently run the light once in the roundabout, slowing entering traffic.
I think this is a logistical nightmare in real life, the more rules and complications you present to system, the more accidents and hiccups there is.
What if i miss my turn? in roundabouts i can easily go for another spin but in this system i cant, I run the risk of beating the next redlight or I can and run the risk of colliding with the incoming traffic
This traffic light roundabout has given me horror flashbacks to a nasty piece of modern engineering next to London Heathrow airport (M4 junction 4). It’s a bad roundabout in practice due to a large number of drivers entering in the wrong lane (the signage and lane markings are poor and contradicting to make matters worse).
The designers of yesteryear didn’t have hindsight for things like this sadly.
Junction 4 + Cherry Lane Roundabout just to the north has got to be one of the most insane road junctions ever made. The bypassed roundabout is actually fully under motorway regulations too since the M4 spurs to the south and a little bit north to the Cherry Lane Roundabout (which is a hamburger/throughabout because of the straight connector from the M4 to the 408). There is also the interesting scenario that traffic can actually enter the straight through section which leads to the motorway regulations but with no legal escape (since the road through the roundabout bans all turns), which is why there are signs warning of the motorway 75 yards ahead. Cherry Lane Roundabout used to be a 'hot cross bun' which is literally a roundabout with a crossroads within it, as can be seen if you go back in time on google street view.
7:52 this is the moment you start making turbo roundabouts.
What makes a roundabout turbo is the shifting lanes. You never have to weave and the inner circle never has to yield to an outer circle. I don't think real real multi-lane roundabouts allow for that, yet your 2-lane straight priority roundabout does.
No, the two lane one is a real turbo as well. You just dont see the lanes shift as obviously without markings.
Shifting lanes is a spiralled lane marking, not a turbo
Having lanes properly shift is how you should design multi-lane roundabouts in reality
That round-a-bout is a work of art
When you realise that myself Eight Line Oneway rode appears here
Cool, thanks👍
I had to drive through a four lane roundabout in a busy city once and it was a complete nightmare.
nice hat right on brand ! well done dude keep up the great work
There is a huge traffic circle type situation in Dubai. It's called the Trade Centre Roundabout. I believe 8 points of entry. Huge traffic circle. 4 lanes. You can have a fun time looking at that situation if you like. Works ok, for the traffic it gets hurt with.