The problem with saying "I'm an IRL road planner this is what should be done" is that this is CS, it has it's own rules LOL

@BiffaPlaysCitiesSkylines

2 жыл бұрын

That is true! 😁

@Futchygu

2 жыл бұрын

@@BiffaPlaysCitiesSkylines It does have it's own rules and therefore it takes a combination of traffic engineering knowledge and game knowledge - but actually CS is surprisingly well simulated. I learnt this early on playing CS when I failed to adequately plan in advance thinking the game logic wouldn't be serious enough to cause problems. Now I use lots of extensive techniques to manage traffic in my cities! I really wish you would do a collab with a real highway engineer as you do your builds because (as much as I like your content generally) you make so many mistakes!

@PerfectAlibi1

2 жыл бұрын

It also needs to obey more to Murphy's laws.

@britishknightakaminininja1123

2 жыл бұрын

That's one of the problems. The other is that just being employed in something doesn't automatically make one great at the job. Name any field of employment and a significant number of those in it are barely competent (and a noticeable percentage don't even quite make competent, even barely), Being employed in a role, in our crazy world of employment politics is usually a sign that you were not good enough to be promoted out of the role yet. (Our entire structure in corporate and employment culture encourages promoting people to their level of bare adequacy).

@erniesmith2579

2 жыл бұрын

The cool thing about “city planner plays” is not modeling real conditions, it’s the insight in the narration to the mindset and the constraints city planners work with IRL. It’s an interesting style of play, not so much for the realism.

I like how you read nord vpn like a bed time story to your children 🤣

@BiffaPlaysCitiesSkylines

2 жыл бұрын

🤣

one thing you have not tried: in a roundabout this big, give incoming traffic a lane to enter, there is enough space of the other traffic to merge right before the next exit

@barthez_

2 жыл бұрын

or a slip lane to the most inner lane on the roundabout 😆

@Zed_Oud

2 жыл бұрын

@@barthez_ yeah, let the existing roundabout traffic dodge the incoming traffic.

@Tibbs_Farm

2 жыл бұрын

I was thinking the same thing. And possibly drop the round-about lanes down to 2 lanes between the off and on, see as how it is only like 5 car lengths,(might be able to raise the speed back) then on the long stretch, like you said... a designated on lane, then allow merging after a short distance. That giant round-about has so much room for options

@PascalDjiknavorian

2 жыл бұрын

@@Tibbs_Farm does not need to be crazy big. Just enough nodes and large intersections/joining so it keeps speed. Lane mathematics always helped, there too it would. Just needs to be adapted to traffic level. The four directions and destinations are not all equal - even with an empty map

@jammiewins

2 жыл бұрын

Yeah the giant one should have its junctions lane managed similar to a highway, as a that's what it effectively is.

10:40 I like how Biffa just naturally starts making the pieces of a turbo when searching for the best way to direct lanes in a roundabout.

@tiagoprado7001

2 жыл бұрын

Yeah, without him ever even acknowledging the people bringing up the idea in the comments of the previous video, all the best suggestions put together naturally led to it.

What I like to do to squeeze more capacity out of my roundabouts, is to let cars pick their exit on entry: most inner lane is 3rd exit, middle lane 2nd, outer lane next. Cars on the roundabout drop one to the outside on every entry point. Pick your exit before you enter, no switching on the roundabout. That way more cars enter in parallel, and you can see the most used routes if you need to make a shortcut.

@yvrelna

2 жыл бұрын

Basically, that's the basic principle behind the turbo roundabout.

@Soinetwa

2 жыл бұрын

@@yvrelna thank you i didnt know how i say this.... anyway.. BIFFA DO THIS!^^

@jamesbedford7327

2 жыл бұрын

I also like using traffic lights, if there is 2 major crossing flows, ill add lights to those entrances and widen the roundabout (e.g. from 2--->3 lanes). this can help smooth out the flow of traffic around the roundabout by letting side roads get out When basic traffic lights isn't enough I try timed, then go for a free-flow option after that (as you do in the actual world)

There seems to be a bias from west towards north. So I'd reckon if we build a bypass lane that way (due to wonky game mechanics) the rest will clear up considerably. Even with a smaller roundabout without other slip lanes.

@Myne1001

2 жыл бұрын

Even Cities Skylines has the infamous south-east rule lol

@leviben7394

2 жыл бұрын

I wonder if a roundabout where they would only use it to get at the 3rd/4th exit would be any good. I.e have a right slip off lane on each of 4 directions and A full straight away bypass×2 bidirectional (N-S + E-W) And the 2 lane for off, 2 lane through on the roundabout is the solution

@droe2570

2 жыл бұрын

That, however, defeats the purpose of the test. The goal is to understand which intersection is most efficient without cheesing the game's wonkiness.

@brohvakiindova4452

2 жыл бұрын

@@leviben7394 at this point you have basically done an incomplete interchange if the AI was smarter, it could increase throughput significantly... you know the selfish behavior in real life where people will switch to the empty lane would help a ton in this scenario as you can see that mostly it's a single lane (mostly middle or right one) backed up completely because the AI prefers the shortest route so they avoid taking the left lane in many instances complicating lane switching further especially on the middle lane

@polissemizando5409

2 жыл бұрын

@@brohvakiindova4452 Slightly increasing the speed limit on the left lane (hold control key with tmpe speed settings), or reducing the speed on the inner ones, will sometimes cause the lanes to balance their loads.

7:29 Look at the right lanes of the two-lane sections entering the roundabout. They can only be used by cars leaving the roundabout at the very next exit. Effectively, those two-lane sections are one-lane now because there's a bypass for right-hand turns. A node between every entry and exit point would come handy where lane switching is allowed. But we know it's against your convictions.

@Craigv93

2 жыл бұрын

Yeah this was poking me in the eyes lol

Traffic lights CAN deal with the amount of traffic on this map. Quite easily :)

@londospark7813

2 жыл бұрын

I came here to point out that you proved that timed lights can deal with the traffic on this map in your video and on stream. 😁😁

another thing that would be wild. have the exits on the inside line. you enter on the outer lanes and have the exit on the inner lanes and the tunnel the exit under the roundabout so the cars exiting will never cross the ones entering.

As long as vehicles coming onto the roundabout are "giving way", there's always going to be a volume of traffic at which the roundabout fails. No matter how good the flow ON the roundabout is, it's the cars stopping to give way is what's causing problems. That's the beauty of the interchange, it allows freeflow traffic in any direction, thus can handle a much higher flow and look empty doing it.

@sventietgen2895

2 жыл бұрын

I think u are right with this! But could we make a larger roundabout (not huge but larger) and give them a dedicated lane on the roundabout (the outer lane) to join? Then they have to merge one node later but still before the next exit node

@michalma

2 жыл бұрын

@@sventietgen2895 Was thinking the same. To have a couple of 6, 5, 4 line segments after each connection. With line connectors allowing only one lane change per node.

@DronesClubMember13

2 жыл бұрын

I agree that the main drawback is the "goes in" parts of the roundabout where traffic is trying to get on. A lot of ideas were nothing more than "pack more cars into the circle" which still has issues because of this. Traffic lights for interchanges become an issue, however. Here we need equal time with some tweaking for the North road (it's less dense). What you don't want is to have tons of cars staring at an empty intersection (which is what we have in my home town but that's another story...). That's where the straight through approach breaks down: programming your lights to do the job and that's not always easy.

@roy_hks

2 жыл бұрын

You don’t need to stop, just merge on PROPER turbo-roundabouts.

@deViant14

2 жыл бұрын

My parents stop at roundabouts a lot whereas I feel like I'm doing my duty as a good citizen if I can get through without braking. CS seems to model my parents' driving.

End of Year Deal! Go to nordvpn.com/biffa to get a 2-year plan plus 1 additional month with a huge discount! 😀

@zanmatoer

2 жыл бұрын

I think you need to check the URL Biffa!

@kaltaron1284

2 жыл бұрын

Is it a coincidence that NordVPN is the sponsor and the nort road gets prioritized?

@Zunedoodle77

2 жыл бұрын

Could you use tolls in order to count vehicles right?

@powerfulshammy

2 жыл бұрын

Flyovers that directly go from north to south and west to east and vice versa should help if that worked IRL in the Philippines should work there too

The sliplanes at 9:00 do not add a lot as the traffic going right spends the least time on the roundabout anyway. The main issue with roundabouts is the crossing traffic: entering versus exiting traffic.

Stretching (or increasing offset if already stretched) the nodes with Node Conroller will help situations on nodes where there are **no intersection** but vehicles are changing lanes abruptly and do causing jammings. With more distance to change lanes, they will reduce the velocity less, if any, and cause less backing up. It will help inside roundabouts if they have intermediate nodes between entrances and exits, without the straight thru "Hugo dare" enabled, but not on the entrance nodes.

@liesdamnlies3372

2 жыл бұрын

Oh hell. I’m kicking myself for nothing thinking about using that on non-highway roads. Because I do exactly that ALL the time with my highways for merging.

Here's a thought... Have all the entrances on the outside of the roundabout and the exits on the inside so that traffic flows concentricaly inward and there is no cross traffic entry or exit. All exits do have to tunnel or bridge their way out to the directions away from the roundabout though. But at least all traffic moves in the same roundabout road. I imagine that it could look like a large toilet. LOL!

@hughesy606

2 жыл бұрын

Interesting concept

@PascalDjiknavorian

2 жыл бұрын

It becomes more of a highway interchange than a roundabout.. but yea, that would work nicely. :)

@John-gv9iz

2 жыл бұрын

@@PascalDjiknavorian I know what you mean, but on an interchange, traffic coming from and going in different directions take different routes. Here, everyone takes a common path for a period of time. This I thought was more the definition of a roundabout than an interchange. 👍

@PascalDjiknavorian

2 жыл бұрын

Good point @@John-gv9iz ! Makes sense. 👍🏼

Maka a normal roundabout with 6-lane 2-way roads instead of highway 1-way. It is faster for cars inside the roundabout and utilizes all lanes in the incoming highways (Left only, Right + Left ,Right only). No slip lanes, no traffic lights, just roundabout properties.

When using the big roundabout you can set the road matematics upgrading 1 or 2 nodes to 6 lanes. With this people could enter the roundabout much easier.

@MonaHerSelfM

2 жыл бұрын

This. When dedicated lanes lead to occupied roads there's no use for those dedicated lanes. Lane mathematics should be applied, especially on the biggest roundabout.

I'd have an over/under solution, where one highway goes above the roundabout, the other goes over and the sliplanes are the ones connecting to the roundabout to let them change direction. I think no matter how big, there's still going to be too much traffic

No conflict left turn junction, where straight on, right, and left, can all go at the same time from two directions without conflict. This will need 2 main traffic light cycles, and 2 sub cycles before traffic enters the left turn lanes. Long cycles will indeed create a back-up, but everyone who were waiting, will be allowed through before a new section of traffic begins waiting.

The time-lapses of the roundabout from overhead are hypnotic, Its oddly satisfying

Being Dutch, where turbo-roundabouts are plenty, nothing about your roundabouts made sense. There should be less lanes in between the entrance and exits to force people to pick proper lanes, like you do on the highway.

@mbrackeva

2 жыл бұрын

The mistake you make here is that you think the game is a traffic simulator. Of course it isn't, far from it. I've been experimenting with roundabouts ingame a lot. And the best ones for high traffic, in my experience, don't really exist in real life.

I dunno if Biffa is going to read this but I'll try. I noticed that the cars getting IN the roundabout are smashing themselves with the cars that are ON roundabout, but the aforementioned are giving way so they have to wait until there is enough space to enter, but the geometric nature of the roundabout forces that all the traffic has to go IN and OUT from the same side, that is, the exterior side of the circle (roundabout). If you can make the flow to flow from INSIDE -> OUT, it might stop the backing up, since cars won't have to wait to get in because those that want to keep going are out of their way. You would have to make tunnels for the dedicated incoming highways, slip them underground, go right and then join on the roundabout, and the dedicated leaving highways won't cause problems since all cars will try to go the dedicated turning lane, leaving free the dedicated keep going lanes. You would have to do plenty of lane management I reckon but it goes like this: 2 dedicated coming in lanes that are coming from the tunnel, on the next node those 2 lanes are forced to merge into 1 keep going lane, on next node that keep going lane is connected to the keep going lane and also to the dedicated turning lane. You also might get away with 3 lanes: 2 for going in and 1 for keep going and also turning off. To summarize, make the traffic going into the roundabout from the actual inside of the roundabout and make then leave from the exterior of the roundabout so they wont smash into each other and wont have to wait for getting in. Hope this make sense, keep up the great content and interesting experiments.

What worked for me well was using a normal set of straight-going roads on the ground and first usable road level above it (9 units of road height in Cities Skylines), a normal roundabout on the next usable road level above the elevated road, and a reverse roundabout above the other elevated roundabout. With a large-enough roundabout, the elevated road stays in the middle of the first roundabout, their maximum height remaining the same. You can also have the reverse roundabout outside the normal roundabout. With the two roundabouts having the same travel-through time, people will mostly use normal right-hand-drive roundabout it to go to the right, but only around half of the drivers going to the left will use it, with the other half using the other roundabout. This way, you can split up the traffic even more. The straight-through traffic would be the fastest, followed by the traffic going right, followed by the traffic going left, followed by the traffic going back. Yes, you can get traffic going back, which makes it even more useful, even though not by a whole lot, especially when you break some other road or route unintendedly. This setup is cheap, too.

It does get deep into the "it's an intersection with a roundabout" debate, but I tend to go with flyover & flyunder (with dedi slip roads for turning right) on intense roundabout junctions so the roundabout is just for turning left and U-Turns. I tend to make dense ones and save to MoveIt for easy implementation elsewhere.

@codeman99-dev

2 жыл бұрын

You mean "it's an interchange with a roundabout" as a roundabout *is* a type of at-grade intersection.

@ChrispyNut

2 жыл бұрын

@@codeman99-dev I used the vernacular that he used.

@yvrelna

2 жыл бұрын

Once you added fly over, you're starting to build the pieces of a turbine interchange, which is basically just a grade-separated turbo roundabout.

Generally, I connect "straight over" lanes. So build a normal roundabout, connect North to South with a bridge or tunnel then East to West. Then the roundabout only needs to handle any traffic turning left or right from their respective direction.

@codeman99-dev

2 жыл бұрын

It's just an interchange at that point. No different than a "dog bone" interchange. Just because the interchange includes a roundabout... that does not somehow make it a roundabout intersection.

@Kibbelingg

2 жыл бұрын

@@codeman99-dev Exactly. One with three levels of separation, which would be very expensive. Although the expense could be justified with this amount of traffic, I think the challenge with optimizing intersections/roundabouts should come from maintaining it to a single level.

I'm learning as much from the experimenting as from seeing the final product. Thanks Biffa!

On the last one, I would make the roundabout itself 4 lanes; the 2 right hand lanes exit at each junction, the 2 left hand lanes continue and are then joined by two new lanes entering from the junction. Incoming traffic won't have to stop and yield, and there's plenty of space for easy lane changes between the junctions.

This experiment definitely demonstrates the interchange's ability to handle much more traffic than any roundabout. At least in the game.

Something i do with big roundabouts sometimes With many nodes in-between With 3 lane highways or big 6 lane avenues Have 6 lane highways as the roundabout road, and allow lane switching on the roundabout, and use the outer 3 lanes as dedicated turning lanes and have the inner 3 lanes go straight on, and sometimes i also allow the in traffic to go ahead instead of yeild, and sometimes with a bit of lane mathematics between the ons and offs, so when you have the 3 lanes of cars going ahead, you also have 3 lanes for them to go onto not 6

I've been watching this discussion about the pro/con for traffic circles, and I have to agree that the first super roundabout shown, worked because it dealt with highway traffic volume. I can't imagine four six lane roads ever being built.

I think I said this in the previous roundabout episode Biffa, but when two highways meet at a roundabout, one will need a flyover and the other will need a duckunder to prevent the absolutely *massive* traffic backups

I'm really enjoying this kind of experimentation Biffa! It could be cool to try this with different or more unusual interchanges to show off how they work and how different tweaks gathered from the comments could either make them more efficient or less efficient

Okay I got a suggestion for the roundabout, make the lane that enters the roundabout to be either over or under the roundabout and enter on the left lane, but the left lane is a pocket so entering traffic doesn't slow down to yield, just how you have them entering the highway. But exit roundabout still the same as you were doing it, so basically a little bit of lane mathematics for inter and the exit roundabout just like you do with freeways. Except they're entering from inside of the roundabout by going underground or above ground. That way there is no such thing that they have to yield for anything they just enter just like they would on the freeway and then Lane change after one segment of road.... Hope it makes sense.

One thing that I’ve had a little success in vanilla play is to make 2 or 3 diamonds with the corners of the smaller diamonds touching the center straight of the larger square depending on the traffic load. NSE&W each have 45 degrees on and off. Because I don’t have the ability to use lane connectors, I use 1 lane ramps and 2 lane roads/highways to force exits and turns. It operates like a roundabout with dedicated lanes but the vehicles ‘in’ the roundabout are turning either at 45 degrees (with 3 diamonds) and/or 90 degrees (with 2 diamonds) so they have to slow down to make the turn allowing oncoming traffic a chance to enter.

It needs in addition to the bypass lanes straight through overpasses. So the roundabout is basically only used for left turns

Nice video. You could also try: 1. Put lights on the roundabout. 2. Traffic coming onto the roundabout comes into a new lane and so doesn’t have to give way to oncoming traffic. 3. Traffic already on the roundabout has to give way to traffic coming onto the roundabout.

The thing about reducing speeds is, as much as it will widen the gap for cars waiting to get on, it will also block them for exactly the same amount of additional time, as the cars on the roundabout are in the way for longer as well. So, at least in theory, it should always be net even and there's no value in it.

What you probably want is a 3-tier split level roundabout that allows the straight on traffic to continue without having to use the roundabout at all but that really takes you into highway interchange territory.

I know the idea is to have “at grade” for everything, but what about small bridges so that (can except for right hand turns) you enter from INSIDE the roundabout?

@jurajklacan6048

2 жыл бұрын

Yes original size or slightly bigger, and inside intake.

@ZL1GHZ

2 жыл бұрын

I was thinking the same thing. If all the traffic on the roundabout entered from the inside, then vehicles would only be changing lanes from left to right on the roundabout, and wouldn't have to give way to traffic crossing to exit at the next road.

@buster2256

2 жыл бұрын

That works but in the end that would resemble the interchange when you think it through (when you don't allow traffic to cross multiple lanes at once). Only difference would be that traffic that goes straight has to do a full circle or more, depending on where your entry points are.

Surprisingly, I love this series! I have a couple of suggestions. 1st: could you check a combined junctions - normal and braced roundabouts(like, slip lanes straight) with traffic lights. Considering amount of traffic in real life, they cope pretty well. 2nd: we are going into bizarre stuff - what if we make rather large 6 lane roundabout, but exits are internal lanes through the tunnels? Vehicles should should swimmingly enter roundabout, change lanes towards center and leave, thus merging while moving without stopping to give way.

@ihti20

2 жыл бұрын

@@RustyWalker Thanks, I've checked junctions you built, that's exactly what I mean. They are normal intersections, not even close to interchange, but work with similar efficiency. It's just to be stressed that large size is essential, otherwise queueing areas will overlap and jam the whole thing, I call it "chockaround". I also don't understand why Biffa avoids building anything close to roundabout. I live in Saint-Petersburg and we have a theatre-about and a big roundabout paved with sett with park in the middle and Mikhailovsky theatre, Philharmonia, Russian museum, Ethnographic museum, theatre of comedy, 5 stars hotel, school, barracks, shopping mall all built up on roundabout and traffic jams never happen.

I think the node controller suggestion was probably for single 2-way connections to the roundabout instead of the two 1-way entrances and exits. You can smooth the curb of a 2-way intersection so much it becomes closer to the entrance/exit smoothness.

One option you didn't try is linked sequenced traffic lights controlling entry onto the roundabout which would give longer bursts of movement on each incoming road. This is something that is used quite often (in the UK at least).

@Selrahcnedder

2 жыл бұрын

This was going to be my suggestion as well. And to be specific, the metered inlets need to be timed as clockwise for right hand drive. This will greatly reduce the start stopping at the inlets that causes the bottle neck.

Magic roundabout? Should equalise the left and right turns a bit

Maybe if the roads off the roundabout were on the inside of the roundabout or alternating (one on the inside, one one the outside and so on)

Biffa, You have to try a three level junction, where straight through is one level in one cardinal direction and underground to the other, and institute a roundabout with bypass to right on the ground level. That would be able to handle this level of traffic.

@martijn8397

2 жыл бұрын

Sounds like a proper interchange :)

If you want to work the roundabout in this szenario you just need one thing: Build either the entry or the exit in the midlle of the roundabout. Then you make sure that oncomming trafic have their own lane by node controler and lane math. that way traffic never needs to cross, it only needs to merge.

I still think your initial conclusion, that a roundabout isn't suited for this type of traffic situation, is the best

The only thing I haven't seen in this video or the last was a dedicated road bypassing the roundabout for traffic going straight over but thinking about that you are getting away from the idea of a roundabout to begin with and heading into interchange territory... been an interesting couple of videos to see Biffa, thank you!

@beajoh

2 жыл бұрын

I've done that straight over or under, and it seems to work pretty well as a lot of traffic wants to g straight through, then the roundabout is only used by those who want to turn left or right. But, as you say, it's not strictly a roundabout at that point. I am also intrigued by roundabouts with entrance lanes that cross over the circle to attach to the circle by coming in from the left instead of the right. This may make better use of the inner circle lane. I don't know.

in Denmark all high capacity roundabouts have a dedicated "turn right" lane just before the roundabout, so if you're only going right you can skip the roundabout. It only helps to a certain limit, but in CS it doesn't make a huge difference unless the majority of traffic has to go right

With the sliplanes, connect the incoming traffic to the inside of the roundabout with a tunnel, so traffic does not have to cross, they can only change lanes to the right. A bit like the Périphérique around Paris.

I was expecting to see the double-decker roundabout. The one where both roundabouts have exits to all directions, but every other connection only connects to each roundabout. so N and S would go in on roundabout A, and E and W would go in on roundabout B. I wonder how it would fare with this heavy density traffic you created for this video. Enjoyed seeing how others recommended certain changes for you and how they turned out. Keep doing what you do, Biffa. Your content keeps my stressed mind relaxed when I'm not able to cope with it on my own. I really appreciate you and your work. I wish I could do more for you, but for now; I'll continue to like and view your videos as much as I can.

Alright Biffa, you've had your fun but there's one last thing you've not tried. One marvel of engineering unsurpassed in all of nature. The magic roundabout of Swindon.

Biffa! I made a suggestion on the last video, the roundabout is being used for cars to turn around to where they came from which is not possible in a traffic light, so if you give them an option to turn around before reaching the roundabout that will save on the traffic using the round about! as always great content.

@BiffaPlaysCitiesSkylines

2 жыл бұрын

1 way a roundabout trumps traffic lights then 😉

You should increase the height of the roundabout and slip the incoming lanes under it and let them connect from the inside of the roundabout. So incoming traffic stops crossing the flow on the roundabout but rather joins it from the left side. Since you keep the leaving of the roundabout on the right side things should go smoother - though we are now leaving the usual design of roundabouts.

The biggest problem with roundabouts is the overlapping of entrance and exit traffic. Have the people entering on the right and exiting on the left, or vice versa, via tunnels. So if they wanted to get off the roundabout, they exit left, one road prior, and have a sweeping tunnel to get off the roundabout. Add in dedicated slip lanes, and you'll have a much improved rounadabout

I always make a super-busy roundabout have at least a couple of nodes between entry and exit, and then limit the lane changing to one lane swap at a time - no crossing 2 or more lanes at once anywhere. It makes a surprising amount of difference, but it is fiddly to set up, of course. With thought though it allows you a great deal of precise control over lane usage and the less lane-switching needed the better the flow (which is why the default spaghetti with one whole road for each possible exit destination that you started with works better than most roundabouts). The more you do to limit lane changing, and especially to changing by 2 lanes at once, the better. It's all about removing the contention for any single lane.

With right turn slip lanes, you could also add, slip lanes North South over the top, and slip lanes underground going East West. If the highway roads are divided they could connect in between the highways on the left, so they don't get in the way of the right turn slip lanes. The result would be right turns have a slip lane, straight ahead has a slip lane over or under, and only the vehicles turning left would need to enter the roundabout.

What I tend to do on those heavyly used roundabouts is to add ways for cars to go straight ahead. A tunnel for north to south and a bridge from east to west having one lane for each direction. In this case I do not have any right turn slip lanes

18:47, 2 lanes into the round, bottom left. Cars were setting on the inside lane to go either straight or left on the freeways. If you set up the lanes in the round as a turbo round, it can force cars to use both entrance lanes correctly. Also, if you are going to use such a large round, have dedicated entrance lanes and have them merge together in the round. Love the video.

@christopherestewart

2 жыл бұрын

Exactly what I was thinking. Traffic coming into the roundabout would not have to stop.

I think you're right that having 4 highways converge like this will always cause problems. At that point you'd have to put in some whammadine interchange like you had before. I would say the usefulness of the roundabout would work in less onerous circumstances (a arterial). If you think about it, the roundabout has some maximum volume of cars so reducing speed or making it bigger only increases that volume which doesn't necessarily fix the massive amount of traffic trying to fit in. It's almost a math equation you could make for yourself...

After seeing the last humongous roundabout I tested a larger roundabout with traffic lights and it works. A bigger roundabout allows for the required buffer space to accomodate traffic lights. I uploaded a short video showing the roundabout in action and also an alternative method using a squareabout.

One thing would actually help a lot with any of those roundabouts. More than anything Biffa has tried: FORCE THEM TO SWITCH ONE LANE OUT WHEREVER A LANE LEAVES THE ROUNDABOUT! Trust me, WORKS WONDERS!

With a big enough roundabout: #1 a 45 degree offset internal reverse direction roundabout. #2 give the existing traffic a slip road (with a much higher speed limit) on the internal side to dodge new oncoming traffic.

Hi Biffa, I love watching your videos. I have one suggestion to try, starting from the large roundabout at the end of this video: When the cars enter the roundabout, use "you go there" + lane maths so that no one gets into the other's way. So for example, 2 lanes of the roundabout + 2 lanes entering, gives 4 lanes. Then gradually reduce it back to 2 (along a few nodes), at each node allowing only limited lane switching (+1 or -1 lane). And before the next exit, add a dedicated lane for leaving the roundabout.... Regards, J. :-)

Adding a second roundabout could help reduce the flow of traffic or putting lanes going under the roundabout so they could drive straight across

Two things: Firstly if you use a one way toll booth you can track the rate cars leave the roundabout. Secondly the more busy the roundabout the slower it should go. It sounds counter productive but you should set the roundabout to like 20kmh

When using a roundabout as a highway interchange you have to put in fly over lanes for the vehicles going straight. In all your tests nearly 70% of the traffic was just trying to go straight across.

Go for the traditional British stackabout. straight across are grade separated , with the roundabout in the middle layer, that way it only has to cope with turning movements. Or have hot cross bun roundabout. Have a normal crossroads, but only for straight across movements and a big roundabout some distance outside the junction for the turning movements

In the last idea where you built the huge roundabout, use lane mathematics! Put six lanes (at least near the entrances and exits) so that cars entering the roundabout do not need to give way.

Biffa couple of things mate. Firstly dedicated right turn lanes don't need to be a separate piece of road you can just use the lane connectors and have a lane that can only be accessed by traffic turning 90° right. This will keep the roundabouts footprint much smaller. Secondly an east-west fly-over would reduce the amount of traffic on the roundabout by a lot which would allow cars from the other directions to enter the roundabout. If that doesn't work a north-south fly-under combined with dedicated right turn lanes would mean that the roundabout would only have to deal with left turns and u turns so reduce traffic on the roundabout by upwards of 75%. Thirdly have a cuppa for me cheers bud.

I'd like to see Magic Roundabout revisited, and even modified. Don't over-complicate building, it really is just interconnected roundabouts, so 4 roundabouts with normal lanes connecting between them forming a loop. I'd consider adding a 5th roundabout in the middle to handle straight over traffic although over/underpass would be better if more expensive IRL.

Maybe you can have both right turn slip lanes and a set of overpasses for straight through so only the left turn people need to use the roundabout. You can also make it smaller again.

I love this kind of videos - "Let's Test Things" You say, is not possible to count the numbers of cars, but, yes its possible, with the Average Traffic Flow tab. Here is a summary of your experiences: 51 % - Slip lane turn right 65 % - Lane conector 60 % - Node controller 62 % - Big Roudabout 77 % - Moon roudabout Ok, the numbers may not be the direct result of the actions, but at least there is a count Great Video!

I have one trick that I haven't seen done almost never. Once you've added slip lanes, Instead of running the roundabout counter-clockwise you should run it clockwise. This may sound counter-intuitive at first since that would mean that roundabout departing cars would be in conflict with incoming cars while exiting, but since left and straight going cars need to drive past entering cars anyway it doesn't make that much of a difference. What you gain with by driving clockwise is that left turning cars are going to turn out on the first exit instead of third. Even though conflict points stay the same when you take extra conflict caused be left turning exits into account (clockwise: left +1, straight +3 / counter-clockwise: left:+2, straight: +2), left turning cars will still use half the circle less space and time in the roundabout overall. It may sound like a weird fix but it really seems to make a big difference according to my experience. Another option is to make the roundabout two-ways by making one lane go left (only left turning traffic is allowed and forced to exit on the first turn) and let other lanes work like a normal roundabout . It requires some forced lane fiddling with traffic manager, but works surprisingly well and should handle more cars than ordinary one once you get it set up right. You can even make a half-twoway roundabout in some cases where the traffic isn't even on all directions. I managed to fix massive gridlock in my last city with such design when I connected incoming and outcoming six lane one-way roads to my main and secondary artery roads. It was a complete mess with normal roundabout, but letting opposing artery and oneway-roads turn to same direction while running the roundabout normally otherwise made a huge difference.

Have a tunnel for north/south traffic and an overpass for east/west traffic. This combined with the slip lanes would make it so that the only traffic that wants to get to the roundabout is traffic that wants to turn left. With lane mathematics and Hugo there, it works really well

Expand on the mahoosive roundabout concept with single lane entry/exit slip roads... they can move between lanes on the roundabout to pick their exit and it would make the entry/exit a lot smoother, also use the lane mathematics between the junctions to go down to 2 lanes!

Considering I've spent the last year attempting to manage traffic in CS, I think I actually have a few suggestions. Dedicated lanes for coming on to the roundabout, go through set up - no give way...! No crossings. (Not that there are pedestrians in this at all.) For something massive like this, I would probably also do dedicated sliplanes for right turns, and tunnels under in both directions for going straight on, too. So only left turns in a four way roundabout would require the use of the roundabout itself. Sliplanes at a speed advantage compared to the roundabout to make it a preferred route. Arguably you're back to an intersection at this point. But I think I'd do it with regular roads instead. I would also stretch each and every node leading up to the roundabout - and all nodes ON the roundabout, too. I would make it large enough that it has two nodes of space in between each off-ramp point, so that the cars coming on to it can manage to switch lanes, since they will likely need to, because they're obviously not going first-right considering the alternative. It also eliminates the need for extensive manual lane-picking inside the roundabout. I've had success with this on very busy industrial areas where even a string of timed traffic lights would fail, which I have been using a lot instead of roundabouts lately.

i was thinking of the roundabout having 2 dedicated lanes that enter and exit, 2 lanes between the exit and entrance turn outs, and 4 lanes around between each entrance & exit. the 2 outer lanes would exit at the next exit, the 2 innner lanes would continue through and merge with the 2 incoming lanes. have a few nodes in between to allow traffic to choose their lane

The M25 option was huge! Once you are that big you should be using lane mathmatics! Whats the smallest roundabout you could make M25 Lane mathmatics work, so Hugo can merge then there is a node or two to change lanes before the exit.

You could also apply lane mathematics to the big roundabout at the end of the video, making the roundabout 5-6 lanes with 3 lanes for going on and off of it traffic, letting them merge instantly on their reserved lanes.

There was no need for 4-lane roads on the slipway variant, since the rightmost lane wouldn't have conflicted with the middle being for both straight and right. Alternatively, you could've gone for a "turbo" variant, where people select their lane *before* coming onto the roundabout and not being allowed to change target direction while on it. That way you'd also get a sense of which directions receive the heaviest traffic by seeing which lanes are backing up, and you could give those specific directions extra lanes or dedicated slipways. I was actually surprised Yumbl didn't try that, since he's done videos on turbo roundabouts before!

I do roundabouts with tightly controlled lane merging, with line markings to match, and with about a 25% speed reduction to the connecting roads. So, whichever lane a car picks will spit them out at one specific connecting road, and they're denied hawky bawky whilst on the roundabouts. Seems to work pretty well, to the point that my roundabouts are probably a little smaller than they would otherwise need to be.

I think the key is to make it in such a way the cars don't have to stop. So the first one is clearly the best, when the cars don't have to stop when just going straight on. But if is has to be a roundabout, how about making a tunnel under the roundabout for the traffic goin into the roundabout, and making them enter the roundabout from the inside? That way they don't have to cross traffic when entering, and they can just move to lanes to the right when inside the roundabout.

I just made a 'roundabout' which had no traffic jamming of any kind but not sure how much of a roundabout it actually still is as it kinda turns into a windmill. 3 lanes coming in. Roundabout is a 3 lane highway with 4 short pieces of 4 lane at the merger to the next exit explained below. Roads connected on the outside of the roundabout are 1 lane in (sliplane) and 2 lanes out. Split 2 lanes off to the right, go under(or over) the roundabout to end up on the inside, connect the 2 lanes up between the 1st and 2nd exit and upgrade to 4 lane highway from the merge point to the next exit. The incoming 2 lanes link to lane 1 and 2 of the 4 lane road and the existing 3 lanes link to 2 3 and 4. From the 4 lanes coming to the exit lane 3 and 4 are only for the exit and lane 1 and 2 connect to lane 1 and 2 on the next 3 lane highway with the 3rd lane being the incoming single sliplane again. The trick here is that at every exit, all the lanes technically shift to the outside by 1 lane. This will allow a car coming from the South to take the sliplane if they want to go East or the 2 lane going to the inside to go North, West or back South. By feeding the roundabout from the inside you almost prevent all cars crossings and that's the #1 bottleneck. To speed things up even more you can increase the exits with node controller to size 30 or use a dedicated angled exit lane so the exiting cars won't have to slow down to get off but that's hard to do if the roundabout is too small.. Traffic was flowing so quickly that it'd probably be possible to remove a lane but I didn't try that. Just be sure the exit lane speed is a little higher than the roundabout speed. I'd post a screenshot but YT will hate me.

The only thing that would help is if you have enough nodes in between the junctions, you can force them into the right-most lane like you do with lane mathematics and get them to cross on the nodes in between. You could also try to force the cars on the highway on to the roundabout and the ones on the roundabout to give way.

What I usually do for busy 4-way roundabouts (not as busy as this though) is to have the entrance road for one way be on the same node as the entrance lane for another. This reduces the amount of nodes on the roundabout from 8 to 4, allows for your roundabout to have less lanes than the amount coming in (for this situation, I would have 6 lanes on the on ramps, 4 on the main roundabout), and, if the roundabout is not handling the traffic adequately, putting in two-phase traffic lights to allow for more bunched up traffic to go around the roundabout. Why have a debate about Traffic Lights vs Roundabouts, when you can have the best of both worlds?

This is interestig. I rly havent used any roundabouts becaus in my experience they just wont work. Because of you videos i did few of them in my industry zones they did work but i can do same with timed traffic lights and save a lot of space.

Crossing lanes is the biggest slow down on this map and irl. What about entering on the left side (inside) and exiting on the right side (outside). This would probably need a large roundabout to work.

Two whacky suggestions 1) Consider adding timed traffic lights with more lanes to the roundabout in key locations to even out the flow? 2) Create an ungodly magic roundabout with one main roundabout alongside multiple satellite roundabouts Also it's definitely not the M25 because the traffic on your roundabout is actually moving 🤣🤣

I'm ps4 and vanilla..... one thing you have not tried is a double roundabout, one on the ground servicing north and south and one raised servicing east and west, this will split the traffic for sure and I guess you can then use your mods to adjust nodes and give way signs etc to have it flow smoother. I always find a with in vanilla mode, I also have the inverted 8 roundabout that I posted last year that could work, magical designs bring magical results sometimes hehe

I think the best way to get this working is to enlarge the roundabout a bit from the original size so that there are more nodes on it and then adjust the lanes as follows: Increase the number of lanes on bulk of the roundabout to four, while cutting the number of lanes on the small sections of roundabout directly opposite the entry point "Y"s to two. This will have the effect of cars entering the roundabout not having to wait for cars on the roundabout at all. Applying lane mathematics to the "Y"s would then yield two lanes off at each "Y" as well. Essentially no turning lanes at all! Try this and I'll bet it looks as good as it runs!

A suggestion for a even more powerful roundabout would be is to make a turbo roundabout but use short bridgesor tunnels to intruduce the striaght and left going lanes in the inside of the roundabout. That way its possible to give everyone a dedicated lane that isnt crossing any other lane. I tested it on that map and even as a smallish roundabout its doing a really good job. I have made a Steamworkshop creation out of it.

The fundamental problem with a roundabout at all is that weaving and merging is required -- exactly the same as cloverleaf interchanges. Even the turbo roundabout Yumbl presented to us a few weeks ago requires oncoming traffic to cross other traffic which, as several have pointed out, is what slows down progress. With the traffic levels in this experiment, I think the turbine windmill (or whatever it's called) in the opening shots is the only efficient method of moving traffic.

What you need here is a Beltway. And outer belt to collect all the highway and interstate traffic that dumps the local traffic onto the inner belt to disperse into the city or stay on the outer belt continue on to the highway or interstate of their choice. It's like a city sized two way double round-a-bout.

Try an hybrid roundabout where the traffic trying to go straight take a tunnel under the main RO. In conjunction with a slip lane to turn right, it should remove 2/3 of the traffic inside the RO. Hopefully this makes it more manageable for the RO. Thanks for sharing your thought process! Not easy to figure out while it is so easy for the viewers to scrutinize!

Given the size of the big roundabout, you might as well just add a six-lane section for a stretch just after each junction, and disallow lane changing for a while... there's plenty of room on the roundabout itself for cars to merge while moving, instead of forcing stationary cars to merge with 100km/h ones at the junction.

I don't remember if I mentioned this on the last video, but I was able to make it work with something /much/ simpler than what you had in the beginning of this. Basically, West/East was an overpass and North/South was a tunnel to bypass the roundabout entirely, and they each connected to a central roundabout with slip lanes for any turning. It ate the traffic up no problem, and had a WAY smaller footprint than that first interchange you had, probably much cheaper too since there was so much fewer bridges. But anything less than that just couldn't take the traffic. I couldn't make anything work for a roundabout, no matter the TMPE, Node Controller settings. Not even a Magic Roundabout (though I may have set it up wrong....)

I'm a city planner, and you should demolish all roads/highways and replace them with mass transit lines and foot paths. But in all seriousness, I bet taking the larger traffic circle and adding dedicated entry lanes would work wonders. That's part of the benefit of making the traffic circle bigger: there's more room for cars to sort themselves, so you can take some of that space and make them dedicated entry lanes. From there it'd just be optimizing how small you can make the circle before the traffic sorting turns into slowdowns.

You should make it magic. Build a two-way roundabout, then put roundabouts at each of the four three-way junctions.

Note that with the sliplanes the roundabout entry roads have a lane still dedicated to direct right turns. That's a defect in the setup.

How I handle it is a 3 lane roundabout with the outer most line being for turning only. the innermost lane is for traveling around and switching to middle lane. And the center lane is for turning into the outer lane. This way traffic can utilize three different lanes to limit the congestion. It's a lot of work with lane mapping but the payout is a hyper efficient solution.