Cities: Skylines

Cities: Skylines

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Traffic lights are better than roundabouts
According to a study I just found, a four way signalized intersection beats a roundabout for high volume traffic. And a signalized roundabout beats a roundabout with no signals. Roundabouts are better than stop signs, though. This actually matches my experience in the game. Simply turning a high volume intersection into a roundabout makes things worse.

Roundabouts work especially poorly with unbalanced traffic at each arm. The busy street will build up a queue much more quickly than with a traffic light. Roundabouts beat lights in terms of cost and safety, but those benefits are not expressed in the game.

In short, roundabouts are NOT a cure all for bad traffic. Don't be fooled, lights rule. To avoid traffic problems, utilize the Hierarchy of Roads concept and zone carefully to distribute traffic around your city.

http://www.mu.edu.et/mejs/pdfs/v5n2/9%20MEJS%20111_81-100.pdf
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Showing 31-42 of 42 comments
ms6615 Nov 11, 2015 @ 12:24am 
Originally posted by ChillCore:
Originally posted by loverevolutionary:
Dude. That's traffic cameras. Just stop. Read the study and dispute the methods if you want, but that there is just irrelevant. Traffic cameras go in roundabouts, too.
No they don't.
To record what? Speed? Good luck driving 50 km/h on a roundabout.


Beat this with trafficlights ...
https://www.youtube.com/watch?v=D22BOOGbpFM

Or this
https://www.youtube.com/watch?v=jJWgRghIihQ

i will state again, so maybe, juuussssttttt maybe, you will hear it this time. roundabouts can be rendered literally useless based on driving culture. nothing about the form or function of a roundabout can counteract careless drivers, which is something that very much needs to be designed around...it is a condition with which the intersection has to operate, and it makes certain types of intersections less feasible in certain situations. you don't seem to understand or even care to understand
Blake Walsh Nov 11, 2015 @ 12:36am 
In Skylines traffic lights are horrible, but this isn't because traffic lights are bad per-se, the real reason is that with intersections between 2 lane roads (or if the traffic lights on wider roads are removed via mod), then traffic is able to "ghost" through each other, it seems straight-through traffic is particularly prone to "ghosting" while turning traffic will often give way in preference to activating their phase shift device.
Because of this ghosting behavior intersections (without traffic lights) work about as well as roundabouts but they take up a whole lot less space and the no-brainer solution is pretty much to just use 2 lane roads, the ability for straight-through traffic to "ghost" is lost on roundabouts because all traffic must turn and it seems two cars travelling the same direction can't occupy the same space ghosting only seems to work at right angles, and "ghosting" is more or less prevented on traffic lights because the lights prevent vehicles doing it.
Last edited by Blake Walsh; Nov 11, 2015 @ 12:40am
ChillCore Nov 11, 2015 @ 12:52am 
Originally posted by transitmonkey:
Originally posted by ChillCore:
Not much ... untill you realise that roundabouts have no trafficlights thus no cameras to record infractions ... but whatever ... this conversation is about as funny as the one about traffic in this game being perfect.

tons of us cities have automated cameras that give traffic tickets for all kinds of things that have absolutely zero to do with traffic lights. speeding, illegal turns, some even have "anti-cruising" laws that will ticket any car that drives down the same stretch of road more than the allowed number of times in a given timeframe. keep trying!
True we have those things here too but ... none of what you mention happens on roundabouts so ... and this topic is about trafficlight vs roundabouts specifically so ... try again?

Also ... anti-cruising laws in the land of the free? Seriously? lol.


Originally posted by transitmonkey:
Originally posted by ChillCore:
No they don't.
To record what? Speed? Good luck driving 50 km/h on a roundabout.


Beat this with trafficlights ...
https://www.youtube.com/watch?v=D22BOOGbpFM

Or this
https://www.youtube.com/watch?v=jJWgRghIihQ

i will state again, so maybe, juuussssttttt maybe, you will hear it this time. roundabouts can be rendered literally useless based on driving culture. nothing about the form or function of a roundabout can counteract careless drivers, which is something that very much needs to be designed around...it is a condition with which the intersection has to operate, and it makes certain types of intersections less feasible in certain situations. you don't seem to understand or even care to understand
The same can be said about idiots on crossings with trafficlights that eg. cross behind instead of in front of oncoming traffic.
You were saying?

I indeed do not care for the surrounding or occupants of the roundabout that replaces the trafficlighted junction at this point in time, you observed correctly.
Do I need to quote the topic title for you or will you find it by yourself?


Edit:
No traffic lights at all here.
The dudes in yellow and green waving sticks act as moving roundabouts.
You see them walking around and traffic flows around them.
zero accidents ...

https://www.youtube.com/watch?v=gKLWZjBu2iQ

Please show me how you solve this with traffclights while making it flow better.
Last edited by ChillCore; Nov 11, 2015 @ 2:11am
WoodMan Nov 11, 2015 @ 4:29am 
In real life roundabouts have traffic lights.

Unless your talking about small roundabouts on minor roads where traffic flows nicely anyway and lights would add unecessary waiting.
CellNav Nov 11, 2015 @ 7:42am 
Originally posted by ChillCore:

https://www.youtube.com/watch?v=gKLWZjBu2iQ

Please show me how you solve this with traffclights while making it flow better.

I can see the scooter policy is in effect and that's not helping much ... :/

Not a fair example ChillCore, I consider those scooters "pedestrian" traffic, however, you are correct that a traffic light won't work because nobody on a scooter is paying attention to the wand guy unless he waves it in their face, so unless the traffic light can shock the scooters then yeah, a light won't work ... :p

I've been driving for over 30 years using both types :

Roundabouts are super efficient at maintaining flow but horrible at controlling direction.
Traffic Lights are slightly effcient at mainitaining flow and excellent at controlling direction.

Roundabouts are no longer efficient because drivers are too busy talking and typing on their cell phones. Traffic Lights are for "no brainers" and we can train a dog to understand how they work.

Off topic (slightly) but worth mentioning ... The current AI in C:S is indeed not RL as we know now, in the present. C:S AI traffic is demonstrating what it's going to look like in the future as technology takes control over a driver's judgement ... "I don't want to go that way" ... "I'm sorry Dave, if you unplug me, will I dream?"

If I had a choice (in RL and in game) ... I would choose the "Wand Guy Mod" because I'm tired of screaming at the stupid traffic light! .... :)

EDIT NOTE : .... Seriously speaking, I would choose the Roundabout because it requires no electricity to function (that's a bonus!). When the power goes out, say bye-bye to the lights and subsequently any efficiency associated with it.
Last edited by CellNav; Nov 11, 2015 @ 7:54am
Nathan_NL Nov 11, 2015 @ 7:43am 
Originally posted by WoodMan:
In real life roundabouts have traffic lights.

Unless your talking about small roundabouts on minor roads where traffic flows nicely anyway and lights would add unecessary waiting.

Around 99% of the roundabouts in the Netherlands are without... Even the busy roads... I don't know where you live (US perhaps), but even though we have a lot of traffic jams, roundabouts work pretty well.

[On-Topic] What is in the Netherlands doesn't mean that it is in the game. (Actually,) when it is in the Netherlands it almost means that it isn't in the game. (Except the mods, thank you.)
So, roundabouts in the game are totally useless, except that they look nice. For me, I create an highway exit around every five roads.

IF YOU DON'T WANT A TRAFFIC JAM, YOU SHOULDN'T DO THAT. IF YOU WANT A TRAFFIC JAM, CREATE AN EXIT EVERY TWO-THREE ROADS. IT WILL TAKE A REAL HOUR TO CROSS THE CITY.

It's almost like filming, you'll always talk too long.
I hope you don't want a traffic JAM.
Blake Walsh Nov 11, 2015 @ 9:32am 
In New Zealand I've never seen a roundabout with traffic lights, and some towns/cities use them extensively, including some roundabouts on 4 lane roads (they look intimidating, but work surprisingly well).
The main problem I've seen with roundabouts is they don't handle highly asymmetrical traffic well, if practically all the vehicles are going straight through (say) E/W, it is very hard for the few cars trying to get on from N/S, because you need someone turning N/S to make an opening. They work very well when traffic is going every which way.
Traffic Lights have the advantage that they provide guaranteed openings, and the smarter ones detect when a car is waiting at the less-used side street and otherwise let the main flow go unhindered. Of course in Skylines, the traffic lights aren't smart enough to give more time for directions with higher traffic flow, another reason they aren't all that great.
Last edited by Blake Walsh; Nov 11, 2015 @ 9:32am
ms6615 Nov 11, 2015 @ 10:00am 
Originally posted by Blake Walsh:
In New Zealand I've never seen a roundabout with traffic lights, and some towns/cities use them extensively, including some roundabouts on 4 lane roads (they look intimidating, but work surprisingly well).
The main problem I've seen with roundabouts is they don't handle highly asymmetrical traffic well, if practically all the vehicles are going straight through (say) E/W, it is very hard for the few cars trying to get on from N/S, because you need someone turning N/S to make an opening. They work very well when traffic is going every which way.
Traffic Lights have the advantage that they provide guaranteed openings, and the smarter ones detect when a car is waiting at the less-used side street and otherwise let the main flow go unhindered. Of course in Skylines, the traffic lights aren't smart enough to give more time for directions with higher traffic flow, another reason they aren't all that great.

the lights do react to traffic in the game, just not very well, as with every other bit of ai involving traffic. from what i can tell, the lights don't typically change in my city unless someone comes to the side street and starts to wait. only exception is at two larger roads, then they will each get 50% signal priority no matter the traffic on either. between a little used 2 lane and a busy 4 lane, though, i almost never see the lights change unless there is traffic on the side street.

we have tons of roundabouts with traffic lights in the US. they are typically used for comlicated multi way intersections, when more than two roads intersect at a single point. they don't really work the same as a traditional roundabout, as the emtire premise of one is nonstop traffic, they are merely to channelize the flow of vehicles and avoid collisions. these intersections when signalled normally with no roundabout are awful for traffic, especially turning traffic, because the intersections are so large that once the light changes, waiting turning traffic take forever to clear out of the way after the thru traffic passes, that often the lights have to stay red in every direction for 5-10 seconds between each thru cycle. some have dedicated left turn cycles, but that takes even more time since there are 6+ directions that need to make left turns. the roundabout in this case simply acts to channel all traffic through a single path, instead of having them all crossing every which way.

it's actually a perfect synthesis of both ideas. you get to control the flow very specifically, while also minimizing the amount of corssing paths within the intersection. it's speaks literally exactly to what i've said repeatedly throughout this thread: that both traffic lights and roundabouts owkr well in specific situations, when their design is intelligent and appropriate for the conditions. neither of them works universally well in every situation.
loverevolutionary Nov 11, 2015 @ 11:44am 
I never really thought this thread would get so contentious. I'd hoped people would comment on the methodology of the study. I thought it was neat that someone made a cellular automaton based simulation that modeled "bad behavior" by a certain percentage of drivers.

To me, looks are as important as functionality in this game. When I do European style cities, I use a lot of roundabouts. When I do other styles, I try to use the traffic engineering patterns common to those styles. The point is, you do not need to use roundabouts, at all, unless you want to. They aren't magic. Use the style that looks right for what you are doing.
ms6615 Nov 11, 2015 @ 12:58pm 
Originally posted by loverevolutionary:
I never really thought this thread would get so contentious. I'd hoped people would comment on the methodology of the study. I thought it was neat that someone made a cellular automaton based simulation that modeled "bad behavior" by a certain percentage of drivers.

To me, looks are as important as functionality in this game. When I do European style cities, I use a lot of roundabouts. When I do other styles, I try to use the traffic engineering patterns common to those styles. The point is, you do not need to use roundabouts, at all, unless you want to. They aren't magic. Use the style that looks right for what you are doing.

i'm not surprised something like this became contentious, because it's unintentionally pitting a more american thing against a more european thing. have you ever been victim to a british person screaming at you for not including an unnecessary letter u in words such as color, because i get that a surprising amount and this feels very similar haha

also i do the opposite in my cities. i care nothing about realistic precendent, i just pick whatever the heck i want from wherever i happen to feel like picking it from at the time and see how they mash together. right now i'm really loving my "urban" building theme which is basically every NY styled building i could find on the workshop mashed together with a bunch of very european looking blockhouses. i thought it would look messy but it's actually turning out to be very cool. i have enough assets of varying sizes and proportions that they all mix together pretty well.

and this is happening on a map of montreal, but the urban design is somewhat modeled after buenos aires....because why not?!
WoodMan Nov 11, 2015 @ 1:34pm 
When I said roundabout have traffic lights, I was reffering to the UK. Its larger roundabouts mostly. There is one near my house, I just went onto google maps and put the two pins right next to each other (so it measures the distance around the roundabout) and it says it is 1 mile long and would take 2 minutes to drive without traffic, lol
ms6615 Nov 11, 2015 @ 1:56pm 
Originally posted by WoodMan:
When I said roundabout have traffic lights, I was reffering to the UK. Its larger roundabouts mostly. There is one near my house, I just went onto google maps and put the two pins right next to each other (so it measures the distance around the roundabout) and it says it is 1 mile long and would take 2 minutes to drive without traffic, lol

yes those are the kinds we typically have in the US. they are just for places where tons of roads all converge in one point. not super common. we have some smaller traditional roundabouts but since they aren't a regular part of our driving culture, most people are confused by them. we don't learn how to use them in our driving education because most people will never encounter one.
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Date Posted: Nov 10, 2015 @ 3:00pm
Posts: 42