I am confident that a double white line does not mean it is illegal to turn left on them under any circumstances (I talked about this here but I wanted to raise awareness to the wider community).
What rule of the highway code in Greece says it is illegal to turn left (as opposed to overtake) on a double white line?
In any case, there is no reason to fragment highways with so many “no left turn” restrictions. In fact, we have a tag to describe overtaking restrictions: overtaking=* (usage).
Article 26 sub 1 Vienna Convention on Road Signs and Signals:
A longitudinal marking consisting of a continuous line on the carriageway shall mean that vehicles are not permitted to cross or straddle that line and, when the line separates the two directions of traffic, that vehicles are not permitted to travel on that side of the line which, for the driver, is opposite to the edge of the carriageway appropriate to the direction of traffic. A longitudinal marking consisting of two continuous lines shall have the same meaning.
Turning left requires crossing the line or at least being on the opposite side of the line, both of which are prohibited.
The question is how does that justify the creation of so many “no left turn” relations to enforce such a rule?
How is it less efficient to use overtaking=* as opposed to the barrage of “no left turn” relations?
Overtaking restrictions between nodes and turning restrictions at nodes are separate restrictions. In this case they just happen to be caused by the same continuous road marking.
For what it’s worth, I think UK signage/markings are generally in line with the convention and the Highway Code says:
Rule 129
Double white lines where the line nearer to you is solid. This means you MUST NOT cross or straddle it unless it is safe and you need to enter adjoining premises or a side road. You may cross the line if necessary, provided the road is clear, to pass a stationary vehicle, or overtake a pedal cycle, horse or road maintenance vehicle, if they are travelling at 10 mph (16 km/h) or less.
Does anyone have the actual Greek implementation of the rules?
The Highway Code of Greece is plain and strict:
- Drivers of road vehicles are prohibited from:
a) crossing the one or two continuous lines, lengthwise, delineate, as well as to
move to the left side of it
Also the offical training handbook makes it more clear:
Also a double (or single) continuous line prohibits in any way crossing it to move to the opposite direction. Where it exists, that is, turning left is absolutely prohibited (e.g. to drive towards a gas station in the opposite direction of the road).
In practice wherever the intention is to allow turning left, the double line is stopped before the junction and continued after it. Example Same road
I remember the phrase “The double line is an imaginary wall. You can’t go through the wall.”
To add to my experience, I had sent an email to my municipality, regarding an intersection where I said turning left was difficult and dangerous because there were many illegally parked cars blocking the view. To “counteract” this they simply banned left turns with a double line without even adding a no turn sign. 
Obviously in practice you would cross the double line to pass a stationary vehicle but the law says nothing about it. Police officers are not crazy, they don’t want to issue fines for reasonable violations. But just to be on the safe side, when this happened to me when I was taking my truck license test, I pointedly asked the examiner if he would let me pass it (and of course he replied “what else?”).
I think the question now is how do we depict such a situation without resorting to use of so many turn restrictions? Surely there has to be a more efficient way.
Think the ways could be tagged with something like change:lanes:forward/backward=through|through;right on a 2x2 laned way with solid single or double centre line without having to resort to cutting things up. Our newly extended 2.5km Strada Pendolo has actually painted arrows on the pavement for those who don’t remember the rules of solid lines (here when a left is allowed the intersections have dashed lines). On Pendolo all side streets have a sign on entering Pendolo that only right is allow and in places even raised yellow kerbs were inserted on the crossings for those who don’t understand the only_right sign.
Country roads here of which many have solid white lines at centre for miles on end (no overtaking signs at starts), have dashed lines where driveways connect to the road. What else to conclude but no left allowed unless dashed. Even side streets that connect to a main just after a traffic island have a dashed section to indicate a left is permitted.
That said the EU traffic rules have an update proposal underway specifically mentioning the rules of crossing one or more solid white lines.
Introducing another additional method to specify turn restrictions is likely to confuse both mappers and data consumers (routers).
Think though it’s the simplest and established too with least risk of breaking v the 3 part “no/only this or that” restrictive relations. Many turn restrictions are useless at that as the navigation software is not responding quick enough to steering mistakes.
Did you question that while I am a driver in Greece, I don’t know the driving rules in my country?
I want to give to OSM data the perfection in details, as much as I can of course.
You should make an other topic, for example why whoever make roads in Greece, does not tag if it is asphalt or not!.
I try to se only OSM data, not using other data like Goggle, but it seems to be in vain.
Lost time and kilometres of road, driving me to country roads without asphalt.
What is that got to do with the problem with you adding so many turn restrictions just to reinforce a no overtaking restriction. Surely there has to be a way to better portray a double white line without resorting to fragmenting the roads.
And if you are concerned about surface information, then we already have surface=* and smoothness=* for that purpose.
1st of all it has to do about the explanation I gave you in the messages.
I told you what’s the rule about single or double continuous painted line in the center of a road.
You thought that I was lying so you asked the rest Greek members for confirmation.
I acted using the available tags to make the OSM reliable, but is seems that you don’t love too much accuracy, even with some more fragmentation…
About surface tag, I never told that there is not such tag, I told you that most users love just to draw a line without looking for further improvement. Since you don’t drive in Greece, surely you don’t care if these information are correct or not.
I have wasted too much time and fuels (= Money) following the routes based on OSM data.!
So, you are incidentally concerned about my changes on the map, and not about ANY user that does not fills the essential tags!
What is preventing you from using overtaking=*?
It has nothing to do with overtaking, but on turning left by stepping on the line.
It doesnt have to do with these signs:
I would advise, to avoid confusion in the future, to use source=* in the relation, such as source=Mapillary (2023-06-25).
