oneway roads/oneway roadsigns

[Mariculous]

Hey there,
Wile working at the remove_excessive_roads bugfix, I again stumbled over road overtaking mode feature, which also needs to be considered for this.

There are two confusing things about this feature:
1. usability:
It is not possible at all to see roads exact overtaking mode without clicking at each single road tile.
The only thing one can do is using the masked ribi tool, which will only tell you if it is one of many (One way, Parallel stop mode) One way modes or one of many (Two way (default), Overtake stationary only, Overtaking prohibited, Opposite lane driving) Two way modes.

2. redundancy:
I know that the road mode feature is much newer than oneway roadsigns, but still, this is redundant.
Is there any other reason for this apart from legacy support?

What I thought about solving both issues is the following:
There should be a roadsign graphics placed at the first and the last tile of a given road mode without placing a roadsign wayobject. Additionally this should be placed in front of and behind crossings.

This given, we could remove oneway signs, for legacy support reasons we have to keep these in the pak for sure but could set them to be never available.
Additionally, this would help with the roadsign issue of the remove_excessive_roads bug, as oneway signs can't be properly moved to crossings but road mode can.

[Phystam]

New oneway sign has new functions from OTRP: we can keep vehicles left or right when the vehicle turns left or right at the next intersection. For the purpose, we cannot remove oneway sign from pakset.

[Mariculous]

Not quite sure but I guess I missunderstood you or vice versa.

I have just setup a test network using OTRP overtaking mode only without any oneway roadsigns and it seems that everything works well.

Vehicles will overtake and can drive in parallel for a long time when they have nearly the same speed even at curves or crossings no matter if both go straight, turn left or right or one turns left and the other one turns right.
Both will use the crossing at the same time no matter if I additionally place oneway signs or not.

This is a really great feature but the only problem with it is that road modes are not visually represented and I don't know why I should still use a oneway roadsign except for explicitly visualizing the oneway road.

[Ranran(retired)]

There is currently no link between the one-way sign and the colorful ribi arrow. (´・ω・｀)
The colorful ribi arrow ignores one-way signs. 
I support Freahk's idea. It will solve that issue. 

[THLeaderH]

2. redundancy:
I know that the road mode feature is much newer than oneway roadsigns, but still, this is redundant.
Is there any other reason for this apart from legacy support?

With oneway roads, vehicles always have opportunity to overtake others. If you do not want to make vehicles overtake others and make the road oneway, you have to use two-way roads and oneway signs.
On oneway roads, oneway signs work as lane affinity signs. This guides vehicles to move to left or right lanes before an intersection.

What I thought about solving both issues is the following:
There should be a roadsign graphics placed at the first and the last tile of a given road mode without placing a roadsign wayobject. Additionally this should be placed in front of and behind crossings.

To specify the mode of roads with roadsigns, you have to put roadsigns for every fragments of the road. This may work well immediately after you construct the road, but after a new road is connected to the road, the mode of some fragments becomes undefined.

[Mariculous]

With oneway roads, vehicles always have opportunity to overtake others. If you do not want to make vehicles overtake others and make the road oneway, you have to use two-way roads and oneway signs.
On oneway roads, oneway signs work as lane affinity signs. This guides vehicles to move to left or right lanes before an intersection.

I have just set up another testmap and couldn't get it working that way (see the attached image). Is there a description about this feature anywhere?
What actually happens is the red arrow. It doesn seem to matter if I tick left and right, only left, only right, or none. They will always prefer the left lane and use the right one only for overtaking only.

Further, isn't a oneway sign visually the wrong way to show that a lane will only be used for right turning traffic?
Shouldn't we better use arrows on the road to show this?

Oneway signs at two way roads don't seem to prevent overtaking, they just make it less likely by using the old overtaking algorithm, which is known to make overtaking in cities nearly impossible. At least this is what I observed.
However, I was wondering why one would want to use this at all. I guess there are some use cases so don't get me wrong, I don't want to drop this but I really can't imagine a situation where one wants to waste a lane.

To specify the mode of roads with roadsigns, you have to put roadsigns for every fragments of the road. This may work well immediately after you construct the road, but after a new road is connected to the road, the mode of some fragments becomes undefined.

I don't want to specify the mode using roadsigns. I want to specify it the OTRP way by setting the mode to the road without any actual roadsigns because this is also relyable on intersections, whereas roadsigns are not. I just want to add graphics to the start and end of a whole line of road tiles using the same mode, so the mode becomes visualized to the player.



The next section is more about how it should work imho to provide a good usability to this very strong, but currently pretty cryptic feature.

To improve OTRP, we need to mainly do two things:
1. Clearly visualize the currently used mode
2. Make roadsigns behavior more intuitive or don't use roadsigns at all for OTRP related behavior.

The OTRP way of oneway signs at oneway roads should be a "One way stay in lane" road mode, instead of a roadsign. When a tile is in that mode, the road will be oneway and vehicles can't change the lane on these tiles. At the next intersection, by deafult vehicles on the left lane can always go left, vehicles on the right can always go right and both can always go straight, if there are roads accepting traffic from that direction. If a lane would not be used at all using this rule, it will allow vehicles on that lane to turn to the other direction.
Additionally, behavior can be configured using a roadsign, or prefarably by directly configuring that tile of road by klicking on it.

So we still need an OTRP way for oneway roads without overtaking:
As OTRP modes already are a combination of drive direction mode and overtaking mode, it sounds totally logical to split these two:
Directional modes: One way, Left-hand Traffic, Right-hand Traffic, One way (Alligned), One way (Parallel stop)
Overtaking Modes: Allowed, Prohibited, Stationary Only
Parallel stop mode and Allign mode are some kind of special as these don't make much sense with overtaking Prohibited.
Additionally, Parallel stop mode should not be set directly but only by bus stops that support this.

As splitting these and implementing the Alligned mode would require some work, we should for now at least use another roadsign than the oneway sign for controlling lanes and we should add some description about this feature. I still don't understand how it works...

[THLeaderH]

As splitting these and implementing the Alligned mode would require some work, we should for now at least use another roadsign than the oneway sign for controlling lanes and we should add some description about this feature. I still don't understand how it works...

Since vehicles change the lane after passing the lane affinity sign, I recommend you to put the sign at least three tiles before the intersection. Then vehicles change the lane considering their course.

As you put it, oneway sign and lane affinity sign are functionally different and should be different sign. The reason why I use an oneway sign as a lane affinity sign is to make use of oneway sign on oneway road.