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...