When do I use traffic signals/stop signs?

[Whirblewind]

So I'm pretty new to the game and I'm noticing most of my city has no traffic signals or stopsigns turned on. To not be on by default concerns me because these are three or four way intersections (usually two lane, sometimes four lane - it looks like they turn on by default at big intersections?) and that seems like an apocalypse scenario IRL. I can't tell if having so few turned on is helping or hurting my traffic. I've tried to look this up in the guides, but the vast majority of the guides seem to be last updated before the expansion that added full control of signals, so I'm a bit lost.

Am I meant to leave these off and have them work like magic? When is the "on switch" for turning signals on? Is there a guide or does anyone have advice on when or when not to use them?

[kristofburger]

Traffic lights are generated automatically whenever a road intersects with four lanes or more. If this doesn't happen for you then something is wrong.

[Whirblewind]

Originally posted by ristosal:

Traffic lights are generated automatically whenever a road intersects with four lanes or more. If this doesn't happen for you then something is wrong.

It does, and I stated that observation. The topic is why do I want to use them and when?

[NewMasterChoco]

I don't know to fix it in-game, but there is a mod where you can manipulate traffic, such as adding stop sign, traffic light, and even change how Cim's cars and other vehicles drive in which lane. It is called Traffic Manager if I remember correctly.

[Whirblewind]

The game has traffic management via Mass Transit so this isn't a discussion for mods nor am I interested in using them, but thanks for the suggestion.

[Metacritical]

adding stop signs and traffic lights is part of the base game and doesn't need a mod to do it.

the game adds traffic lights when it thinks they are needed. generally this is fine but it can cause traffic problems when junctions are too close together so i tend to remove traffic lights and replace them with stop signs when the main road has higher through traffic and the side roads get little. it's not something to get too bothered by however, and the best time to remove traffic lights is when they are causing huge tailbacks.

[Whirblewind]

Originally posted by Metacritical:

adding stop signs and traffic lights is part of the base game and doesn't need a mod to do it.

the game adds traffic lights when it thinks they are needed. generally this is fine but it can cause traffic problems when junctions are too close together so i tend to remove traffic lights and replace them with stop signs when the main road has higher through traffic and the side roads get little. it's not something to get too bothered by however, and the best time to remove traffic lights is when they are causing huge tailbacks.

I feel like I'm missing something. I want to know when the game (or the player) thinks they're needed so I can decide for myself why I would want to add or remove them. Right now I don't understand.

Let's be explicit about this because I can get vague from google and vague isn't making sense.

Examples:
1. Zero traffic signals or stop signs.
2. Zero traffic signals and stop signs at major arterial intersections. What are the signs doing for me compared to example 1?
3. Traffic signals at major arterial intersections. What are the signals doing for me compared to 2's stop signs?
4. Traffic signals at collectors and intersections. Why would I increase the number based on what they do for me? Google says don't do this ever, despite how it works in real life, and I hope answering points 2 and 3 helps me understand why.

[Metacritical]

risotal told you when the game adds them, which answers questions 1. if the game adds them then i leave them alone unless their presence causes hugh tailbacks, in which case i remove them. cars don't crash in the game so it doesn't matter if they're there or not.

stop signs stop traffic, just like in real life. what do you class as major arterial roads?

traffic lights control the traffic whereas stops signs just stop the traffic, and the cars move when it's free to do so just like in real life. only as there are no car accidents it may look like chaos.

what do mean by collectors?

[sindar]

Nearly a year ago grapplehoeker had posted a very informative response to a similar question. Maybe his repsonse is of use to you. The question was: "What is the point of traffic lights and stop signs?":

Originally posted by grapplehoeker:

They permit the control and timing of conflicting flows of traffic at an intersection.
While a fixed priority sign provides a permanent right of way for two flows in a longitudinal direction for example, it will impede any lateral movement. In situations where traffic volumes in opposing directions are heavy, this will become a bottleneck for the flow that has to give way.
A traffic light system allows for both longitudinal and lateral flows to have alternating rights of way.
This is a valuable system for handling large traffic volumes to help an intersection flow smoothly and equally for all directions.

[kristofburger]

Originally posted by Metacritical:

what do you class as major arterial roads?

what do mean by collectors?

Look up hierarchy of roads.

[Whirblewind]

Originally posted by sindar:

Nearly a year ago grapplehoeker had posted a very informative response to a similar question. Maybe his repsonse is of use to you. The question was: "What is the point of traffic lights and stop signs?":

Originally posted by grapplehoeker:

They permit the control and timing of conflicting flows of traffic at an intersection.
While a fixed priority sign provides a permanent right of way for two flows in a longitudinal direction for example, it will impede any lateral movement. In situations where traffic volumes in opposing directions are heavy, this will become a bottleneck for the flow that has to give way.
A traffic light system allows for both longitudinal and lateral flows to have alternating rights of way.
This is a valuable system for handling large traffic volumes to help an intersection flow smoothly and equally for all directions.

An actual answer, thanks! The wording fits for real life as well as in game. I have lingering problems of knowing when a signal is better than signs, or when to add signals/signs when the game doesn't do it for me, but this helps a lot as a jumpstart.

[onezerorising]

Just be aware that traffic lights never improve traffic flow. Not in-game and not in real-life. What traffic lights do is share priority between opposing traffic streams where ordinarily traffic can't be relied upon to do so autonomously. In real-life this boils down to 'nobody will yield to let me out'.

If/when traffic volumes reach some undefined level, (different intersections will have different 'saturation points'), traffic lights will not help. Traffic light control afforded by such mods as (the excellent) Traffic Manager: President Edition will not help. Over the volume threshold, all that works is re-routing and/or major road-network re-thinks....

[MarkJohnson]

Originally posted by Whirblewind:

So I'm pretty new to the game and I'm noticing most of my city has no traffic signals or stopsigns turned on. To not be on by default concerns me because these are three or four way intersections (usually two lane, sometimes four lane - it looks like they turn on by default at big intersections?) and that seems like an apocalypse scenario IRL. I can't tell if having so few turned on is helping or hurting my traffic. I've tried to look this up in the guides, but the vast majority of the guides seem to be last updated before the expansion that added full control of signals, so I'm a bit lost.

Am I meant to leave these off and have them work like magic? When is the "on switch" for turning signals on? Is there a guide or does anyone have advice on when or when not to use them?

In theory, you will never use a stop sign or signal in this game. The only time you want to use them is when traffic temporarily gets heavy. They you have to watch traffic flow to determine if you should use lights or stop signs. But if your city is in balance, then neither are needed.

[Whirblewind]

Solid couple of replies, thanks guys!

[Ben Gunn {FNF}]

Top left side of screen has the "info panels", open it and see overlays for schools,fire departments,pollution,etc. . The bottom right icon deals with roads.Open it and there will be 3 categories, the center one deals with traffic signals. When you zoom closer to an intersection, you will see the possible signals that are in place. Bright colors indicate that a signal is in use,greyed out signals are not in use. Simply turn on (or off) any signal with a click of your mouse pointer. Remember that vehicles never crash into each other, so congestion is not always a bad thing,as long as you have a steady flow of traffic. Small roads intersect with no signals, larger ones usually generate traffic lights.
I prefer to disable signals at highway on/off ramps, and try not to build other intersections too nearby.
Give your industrial area good access to highways,rail, and ship terminals that dont route through your city. Truck traffic gets very heavy. Public transport will help reduce the volume of your automobile traffic in town.

[OneJasonBradly]

Originally posted by onezerorising:

Just be aware that traffic lights never improve traffic flow. Not in-game and not in real-life.

Over use of lights will slow flow but without them traffic jams and stalls can\will occur also reducing flow. My main street was a mess until I installed traffic light to control the volume collecting on the cross streets. They can improve flow when used in the right places.
https://steamcommunity.com/sharedfiles/filedetails/?id=776084563

Originally posted by onezerorising:

In real-life this boils down to 'nobody will yield to let me out'.

In game too, this is the very reason to change from stop sign to lights. When the volume waiting to use the intersection gets too great on the cross streets. I use them when a main street crosses another main or a heavy collector road.

@Whirblewind
You being from Toronto, think of Bloor street. There are no stop signs on Bloor St. only traffic light at certain intersections. Now look at all of the “other” street crossing Bloor, they have stop signs to Bloor St. Can you see the difference that constitutes lights. I consider Bloor St. to be a collector road for residential areas off it. The lights are required when the volume on Bloor crosses another major road like Bathurst St. or Dufferin St. or Keeke St.