Talk:Red turn

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Is red_turn:straight ever sensible?

What is a situation where red_turn:straight makes sense? In what way can this be considered a "turn on red", since it is in fact going straight? I would think a different key, like straight_on_red=yes. --Jeisenbe (talk) 04:21, 11 October 2020 (UTC)

Do you need a separate key because turn left and turning right is using a different verb than "going straight"? Linguistically, yes, it's a different wording: "turning" vs "going straight". But in the case of this tag, the action is the same" You ignore a red light. So I'm against adding yet another tag, just because you don't "turn". --S8evq (talk) 12:37, 11 October 2020 (UTC)
Indeed, a different tag for this wouldn't make sense. Now red_turn might not be the best name (is there even a name for that in English?) but it's what was already established. —M!dgard [ talk ] 12:51, 11 October 2020 (UTC)
In American English we say "right turn on red". E.g. the signs say "No turn on red" (since normally a right turn is allowed on red), or ""No turn on red except bicycles". See - clearly "going straight on red" does not fit in this category. --Jeisenbe (talk) 15:50, 11 October 2020 (UTC)
"in the case of this tag, the action is the same" You ignore a red light." That might be true in your country, but in North America and many other places where human life is given little value, it is standard that right turns (with right-side traffic) are allowed at all traffic signals, unless otherwise stated, if there is no traffic. The idea is that you are not violating the light since you are just turning right into the near-hand lane. This assumes the absence of pedestrians and bicycles. So no, "right turn on red" is not considered the same as "ignoring a red light". --Jeisenbe (talk) 15:55, 11 October 2020 (UTC)
Then UK, France, Germany, The Netherlands... for instance are given value to human beings ;-). Even with those country, region... -specific rules, the action is the same: bypassing the traffic light indication. Note the example: in Western Europe at least those specific rules are generally valid only for bicycles. So the situation is the same: can we ignore the indication of the traffic light and continue our trip - with less priority than people moving "by green".
In USA, you don't need to write right turn possibilities if it's valid in the whole country (I'm aware of signs specifying that red turn right is forbidden, but I don't know if the rule is state dependent or not) - thanks Nguyễn for the clarification below.
In France if it's for generic traffic, a specific light will indicate it (usually using a specific lane). The illustration of red_turn:straight:bicycle=yes is the French M12b sign, see Journal officiel électronique authentifié n° 0023 du 27/01/2012, page 3.
Better tags may begin with ignore_red_light --Nospam2005 (talk) 19:38, 13 March 2021 (UTC)
At least in Germany it's not about ignoring a red light - you still have to stop at the red light but are allowed to continue if traffic allows. --Mueschel (talk) 11:06, 27 March 2021 (UTC)
In France it's the same as a "give way" sign, so not a full ignorance of the traffic lights either, let's call it an overwriting rule. --Nospam2005 (talk) 11:01, 2 September 2021 (UTC)
@Nospam2005: In the U.S., right turns on red are allowed by default in every state but prohibited by default in New York City, which suggests that there may be other cities where they're prohibited by default. There are several states where a right turn on red may be prohibited by a red arrow traffic signal rather than an explicit sign. In some states, only the rightmost lane is allowed to turn on red, while in California, every right turn lane may turn on red unless a (very rare) sign says otherwise. (As someone who learned to drive before moving to California, I was unaware of that unadvertised but apparently popular rule for over a decade.) – Minh Nguyễn 💬 21:38, 7 July 2021 (UTC)
I'd suggest using 'through' instead of 'straight' - that fits to the possible values for 'turn' tags. The "turn" tag should also serve as an argument to use "turn" in combination with 'going straight'. --Mueschel (talk) 11:06, 27 March 2021 (UTC)
We have more than one thing to describe: what lanes are concerned, what is the behaviour on red (stop or give_way?), so for a single lane we could have something like strait=stop;right=give_way. Do we need this complexity? --Nospam2005 (talk) 11:01, 2 September 2021 (UTC)
@Nospam2005: There's some overlap between the concepts discussed here and in Proposed features/wait (which was rejected in part because of a disagreement about whether to tag nodes or ways). Basically, if we wanted to solve all these problems at the same time, this would be an "on red" variant of wait=*, though some of these problems are much more common than others. – Minh Nguyễn 💬 18:31, 2 September 2021 (UTC)
Right, if we want to solve all cases, the next section Use Relation:restriction_instead is the way to go. As often, French people are fine with relations and Germans are trying to avoid them! --Nospam2005 (talk) 19:09, 2 September 2021 (UTC)

Use Relation:restriction instead


Wouldn't it make more sense to use something like restriction=no_right_turn_on_red or restriction=no_left_turn_on_red, instead of red_turn:right=no? See --Jeisenbe (talk) 16:02, 11 October 2020 (UTC)

A relation would make sense, though I'd like to see something other than restriction, for one because we have to map the opposite over here and "restriction=right_turn_on_red_allowed" looks contradictory. —M!dgard [ talk ] 09:18, 13 October 2020 (UTC)
A relation would make sense to me if with it is become easier for a bicycle router to decide that it can ignore the traffic light. For that a clear description of how the relation members and roles look like and some thinking if it easy to implement by a bicycle router.
See also Talk:Tag:highway=traffic_signals#Right_turn_on_red -- Emvee (talk) 19:19, 13 October 2020 (UTC)
See Proposed_features/turn_signals#Right_turn_on_red (directly) ---- Kovposch (talk) 17:58, 15 October 2020 (UTC)

@Jeisenbe and Kovposch: Yes, it's a problem that the article recommends tagging a highway=traffic_signals node. It does require tagging individual stoplines as traffic signals to address the very common situation that a turn on red is allowed in one direction but not another, but tagging the intersection node as a traffic signal is also valid and well-supported. (It isn't always possible to accurately map the traffic signals at the stopline, because the stopline often varies from lane to lane.)

In general, it's inappropriate and fragile to use a tag on a node to refer to a maneuver that could involve an arbitrary way two or three connections away from the node. Throw No Turn on Red Except from Left Lane or No Turn on Red from This Lane into the mix, and it becomes quite awkward that red_turn:left:lanes:forward=* on a highway=traffic_signals node can say whether to treat the node differently when headed towards one of several indirectly connected ways. traffic_signals:turn=* is even worse, because it looks like a variant of turn=*, but it mixes the | syntax of *:lanes=* with novel values that aren't valid for turn=*. If this were workable, we might as well have mapped turn restrictions in the same manner. Better for a relation to explicitly include the affected Role from and Role to ways to remove any ambiguity.

 – Minh Nguyễn 💬 01:41, 8 July 2021 (UTC)

I don't see how positional precision would be an argument against the practice when the same would apply to an angled or by-lane highway=give_way and highway=stop. traffic_signals:turn=*'s separator syntax isn't a fatal flaw. The punctuation in combination with semi-colon can be changed. For roads, connectivity=* already uses a comma. Indeed, you can compare turn:lanes=* for their different uses. traffic_signals:turn=* is only representing the arrows, and their meanings. It doesn't show a movement. It and relation:restriction aren't mutually exclusive. ---- Kovposch (talk) 03:01, 8 July 2021 (UTC)
A comma would certainly be less confusing than a |. I think it's telling that the proposal has to clarify that "the vertical line '|' does not indicate per lane signals". I'm still unclear on how the proposal would represent per-lane turn-on-red restrictions. In principle, I don't know why we need two completely different ways to model turn restrictions/allowances versus turn-on-red restrictions/allowances. – Minh Nguyễn 💬 20:37, 12 July 2021 (UTC)
@M!dgard: I'm responsible for almost all the restriction=no_left_turn_on_red relations and a large portion of the restriction=no_right_turn_on_red relations so far, though another mapper coined the tags originally. So far, these tags have only been used in jurisdictions that allow turns on red by default. In a jurisdiction that prohibits them by default, I suppose mapping all these restriction relations would be problematic in the same way that U-turn restrictions aren't mapped in Brazil. A new relation type sounds fine to me, as long as we continue to use Role from, Role via, and Role to, which are already well-established as part of Relation:restriction and Relation:destination_sign (and some other relation types like Relation:manoeuvre). – Minh Nguyễn 💬 01:41, 8 July 2021 (UTC)

This is tagged a lot in France as restriction:bicycle=give_way, which while not entirely sensible as discussed above reads ok. CyclOSM also renders it. --Brainwad (talk) 11:05, 19 March 2021 (UTC)

@Brainwad: I think it's problematic that this article conflates two kinds of regulations, which should have distinct tagging:
  • Allowing or prohibiting vehicles from turning at a red light after coming to a complete stop No Turn on Red No Left Turn on Red No Right Turn on Red Right on Red Arrow After Stop No vire en rojo
  • Allowing vehicles to blow past a stop sign or red light without stopping, treating it as a yield (give way) sign StopExcept Right Turn Continuous Right Turn With Caution
Throughout the U.S. (except New York City), motor vehicles and cyclists are allowed to turn on red, after coming to a complete stop, unless otherwise posted. A few states allow the Idaho stop (treating a stop sign as a yield sign by default), but cyclists may never treat a traffic light as a yield sign anywhere. Occasionally, a stop sign may have an Except Right Turn plaque indicating that motor vehicles and cyclists may treat a stop sign as a yield sign when turning right, without having to come to a complete stop. There isn't an established way to tag Except Right Turn, but to me, the French M12a sounds much closer to StopExcept Right Turn than Right on Red After Stop. Maybe I'm misunderstanding how the French sign is used though.
 – Minh Nguyễn 💬 01:41, 8 July 2021 (UTC)
With the Belgian B22 a cyclist may treat a red or orange traffic light as a yield sign. I don't know about France. —M!dgard (talk) 01:13, 9 July 2021 (UTC)
My point is that a yield sign is not the same as a turn on red: with a yield sign, you can proceed without ever stopping, whereas you have to come to a complete stop before making a turn on red. This distinction is normally true for every kind of vehicle that I'm aware of, though I wouldn't be surprised to learn that trucks and school buses must come to a stop at a yield sign in some jurisdictions. – Minh Nguyễn 💬 20:31, 12 July 2021 (UTC)
It seems to me that the entire page as it is right now is about the maneuver of yielding when turning, specifically in the bicycle case. The only conflation is with the page title "Red turn", which some languages/regions interpret as referring to the maneuver of turning after stopping. Unfortunately Britain seems to have neither of these cases, so we can't fall back to using a British English term to disambiguate, as is OSM norm. But how about moving the page to Key:red_turn? --Jarek Piórkowski (talk) 03:17, 14 August 2021 (UTC)
I have now seen that red_turn:right=* is recommended by German tagging for their right-turn-on-red signs: DE:Tag:highway=traffic_signals#Zusätzliche_Tags. The German right-turn-on-red requires (at least legally) a stop before proceeding. red_turn:right=yes_after_stop might have been a less ambiguous value... --Jarek Piórkowski (talk) 05:08, 14 August 2021 (UTC)
@M!dgard:, for France the very similar sign has the exact same meaning ;-), i.e. a yield - without requiring a stop - is possible, you have to give way not less, not more, that the general meaning of the triangle with an upper horizontal edge. --Nospam2005 (talk) 19:01, 2 September 2021 (UTC)