3 lane road, only one lane used

[DLM]

Hi! I was hoping you guys could help with an issue that has bothered me forever in my city. I have a large and busy avenue that looks silly because traffic mainly wants to use one lane to enter the roundabout at its end (here the left lane):
http://steamcommunity.com/sharedfiles/filedetails/?id=1085805817

I have installed Traffic Manager President Edition for this sole reason to hopefully split the vehicles more evenly on the 3 lanes. But all I managed to achieve is moving the traffic to another lane, here on the middle lane (notice how they actually use all 3 lanes now... only to merge to the middle one when approaching the roundabout):
http://steamcommunity.com/sharedfiles/filedetails/?id=1085807370

I have tried different set of rules on this roundabout, being either very restrictive (few options to swap to a different ring, outer ring for exits only) or permissive (you can enter any ring of the roundabout, more options to change lane, outer lane used for exits and going around), forbidding any lane change on the avenue, etc. but nothing really makes the traffic use all 3 lanes.

Is it simply impossible because of the way the AI was designed? Or I just haven't seen the solution yet? Thanks for any help

[BLÀde]

welcome to real life

[Metacritical]

click on guides at the top of this page and search for traffic. there are plenty of guides to help.

but briefly, if you have a three lane road, left is used for turning left, middle is used for going straight on, right is used for turning right. if you don't provide left or right junctions then only one lane will ever be used.

[Lorax]

Well I mean in real life if the road leads to a bottle neck it doesn't matter how many lanes it has because the only point they can get off at is the end. Like you COULD fill all lanes but only 1 car at a time can enter the round about. Big roads work better with lots of small roads branching off them

[mrjoker]

You should try make multiple locations for people to enter the city or leave. Spreading traffic is the way to fix and avoid bottlenecks. (*And cargo trains)

[OneJasonBradly]

The right hand lane in this case is reserved for vehicles wanting to go to Daffodil St. The center lane here seems to be your entry to the roundabout lane. The third or left lane is not being used I think because it would be too difficult for the vehicles to lane change twice to get to their exit destination (not quickest route).

[mlind1981]

@OP Your problem is easy to spot you need to "force" traffic in to the right lanes before the roundabout. You have made guide lines in the roundabout but the roads leading into the roundabout is where the mess starts and cars will merge and lane change as they like. Take a look at some of the pictures I recently made public to see for yourself what I mean. Your problem should be quite easy to fix.

[OneJasonBradly]

Originally posted by Metacritical:

but briefly, if you have a three lane road, left is used for turning left, middle is used for going straight on, right is used for turning right. if you don't provide left or right junctions then only one lane will ever be used.

As logical as that sounds that statement turns out to be untrue. Lane designation (arrow markings) is determined by the lanes ahead or coming off that road piece.
For Example I have used 6lane one ways and all lanes were right turn only or left turn only and or ANY combination of the directions. Including “3left only, 1 straight only, 2 right only” mods though convenient are not required. There is more freedom/flexibility in the creation of roadways and intersections than you have experienced so far.

[OneJasonBradly]

I don't have much or any experience with roundabouts, but using the 3 lane highway as the roundabout could share in the difficulty of its operation.

[kristofburger]

Forget all the lane connector stuff because your problem is fundamentally elsewhere. There's too much volume through that roundabout and into one or two directions. Either come up with a faster route for these cars, rezone, or completely redesign/remove that intersection.

[AoD_lexandro]

5 roads in to one round about is a no no. Thats why traffic is so bad there, a single "normal" round about should only have a max of 4 roads leading in to it. Either bulldoze it and make two seprate juntions, or remove a road and send the traffic elsewhere.

[DLM]

Originally posted by AoD_lexandro:

5 roads in to one round about is a no no. Thats why traffic is so bad there, a single "normal" round about should only have a max of 4 roads leading in to it. Either bulldoze it and make two seprate juntions, or remove a road and send the traffic elsewhere.

Traffic flow is not much of an issue, it is pretty fluid, the avenue is even long enough that the long lane doesn't impede anything and vehicles are not stuck either, they enter the roundabout at a decent pace. The "issue" is mostly esthetic as it looks ridiculous to have everyone on one lane.

Originally posted by Metacritical:

but briefly, if you have a three lane road, left is used for turning left, middle is used for going straight on, right is used for turning right. if you don't provide left or right junctions then only one lane will ever be used.

This screenshot is only one of the several configurations I tried.

Either on the roundabout itself by restricting the outer ring for exits only or by allowing vehicles to continue on (which lead the traffic to use the right lane only on the avenue since they could just use the outer ring to go anywhere), by allowing different lane changes from the middle ring.

Either on Elk avenue entering the roundabout, by forcing vehicles on the right lane to use the outer ring, on the middle lane to use the middle ring and the left lane to use the inner ring, or by allowing to enter an extra ring.

No matter the configuration, the traffic will still use one lane of the avenue. I even made an attempt where any lane change on the avenue was forbidden. I let the simulation run for a bit, it kinda worked at first and traffic was more evenly split on the 3 lanes then at one point the AI caught up and actually entered the avenue on the lane it would favor to enter the roundabout and they were all back to flock to one lane.

[AoD_lexandro]

The distance between the junctions on the roundabout means the AI has no time to change lanes, which is why they are flocking in to one lane. As I said, 4 roads max for equidistant exits that give the AI time to shift lanes in the roundabout itself.

That and make more exits on the main route, so the ai can change lanes before the roundabout.

[DLM]

Originally posted by AoD_lexandro:

The distance between the junctions on the roundabout means the AI has no time to change lanes, which is why they are flocking in to one lane.

On this configuration of the lane director? Are you sure? Because the middle ring constantly allows to change to the outer ring to exit the roundabout at any time which IMO is the reason why in this configuration they all use the middle lane: entering the middle ring allows to go anywhere.
It seems to me that the AI is actually "lazy" as in it will use the closest lane that leads anywhere, as I described in my last comment as soon as I allow the outer ring to go forward (instead of being restricted to exit) the traffic all flocks to the right lane of the avenue since it enters the outer ring and it allows them to move anywhere.

And again, without any mod, without trying to force the traffic to do anything, this is the way the AI would behave (my first screenshot is 100% vanilla).

[AoD_lexandro]

Fairly certain. I have a lot of roundabouts in my current city.

[Palpatine001]

Welcome to real life inside a City.
Snark aside use the Lane Connectors in the TM:PE so say the left lane and middle lane goes left, the middle and right lane goes straight through, and the right lane goes right.

Also adding another lane in the roundabout will give you a dedicated turn lane to supplement the the other turning lane spreading the load. But make sure the TM;PE lane connector ise used