Proposal:Extended traffic signals tagging
| extended traffic signals tagging | |
|---|---|
| Proposal status: | Draft (under way) |
| Proposed by: | Lukas458 |
| Tagging: | traffic_signals:standby_mode=* |
| Applies to: | 
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| Definition: | Two new keys for describing whether some "special" traffic signals have a standby-mode and what kind of it is; to differentiate between the purposes and the configurations of traffic lights. A "yellow blinking" traffic signal for example can have very different purposes, and "blinking" can be the "standby"- or the "active" mode. |
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| Rendered as: | no rendering |
| Draft started: | 2020-05-10 |
An explanation of the problem first
There is a problem we have with the actual existing values of traffic_signals=*. These values are mixing up something:
- 1. Some values are saying something about: For what is the traffic signal used? What is it's purpose?
Example: traffic_signals=tram_priority is used to give appearing trams priority. But it says nothing about the configuration of the signal. That it turns to red if a tram appears, is clear. But is it green at normal times? Or off? Or does it blink yellow at normal times?
It's the same with traffic_signals=ramp_meter for example. To control the traffic flow to a motorway is rather the traffic light's purpose than its configuration. It is nothing said about how it is configurated when not being active or something.
The same thing we have with traffic_signals=emergency, traffic_signals=bus_priority and also with traffic_signals=crossing_only I proposed here:
- 2. Some values of traffic_signals=* are saying something about: How is the traffic signal configurated?
Example: traffic_signals=blink_mode describes: "a normal traffic signal that can be activated, but is normally set to blink. It may be changed to normal operation in the future when an intersecting road is completed, or may be used only for special events." Okay, it's about the configuration. But there is nothing really said about it's function, the definition leaves it very open, to me. A blink-mode signal can have different purposes:
- a warning signal that warns all the time that cars have to give way at some near point (but without controlling this point in any way)
- a signal that has the function of an "advance advertiser", which is warning the cars on a road with higher speed that an intersection with a traffic light will appear on which they will have to stop
- a crossing-only traffic light that is blinking yellow all the time when not activated by a crossing pedestrian (if activated it changes to red)
- a crossing-only traffic light that is "off" by default and blinking yellow for the cars when the crossing gets activated by a pedestrian (you see the difference, right?)
So you see, a blink-mode traffic light can have different influences on lane-traffic. Sometimes it is used just as a warning signal, but cars would never have to stop at it. In other cases lane-traffic has to stop there, because the traffic light flashes yellow when a pedestrian wants to cross. These are the crossings with amber flashing lights. Here is an article about it: https://www.tampabay.com/transportation/those-crosswalks-with-amber-flashing-lights-are-everywhere-some-dos-and-donts-20181228/
Furthermore, with actual tagging it would not really be possible to combine "a normal traffic signal that can be activated, but is normally set to blink" (as the definition of traffic_signals=blink_mode says) for example with traffic_signals=emergency, so when an emergency signal is meant that's usually inactive (blinking yellow = "proceed with caution") but can be activated (red = "stop") to clear the intersection for emergency vehicles.
Rationale
We need to differentiate between "For what/for which purpose is a traffic signal used?" and "How is a traffic signal configurated?".
My propose is to put the "For what/for which purpose is a traffic signal used?" into traffic_signals=*. Why? Because we have some purposes already there: traffic_signals=emergency, traffic_signals=bus_priority, traffic_signals=tram_priority and traffic_signals=ramp_meter are those. Also my originally proposed traffic_signals=crossing_only would be one.
As I described, a "yellow blinking" traffic signal (actually tagged as traffic_signals=blink_mode) can have different purposes, so we need to differentiate here.
Proposed keys
In my eyes, the following kinds of traffic signals are on-demand ones. Most of them are only activated on-demand, but their difference is, that this "on demand" is for different purposes:
- 1. traffic_signals=bus_priority
- 2. traffic_signals=tram_priority
- 3. traffic_signals=emergency
- 4. traffic_signals=crossing_only
- 5. (maybe also traffic_signals=ramp_meter is activated on-demand only, too.)
These traffic lights have a standby-mode (the traffic signal is "sleeping" by default, but can be activated) and an influencing-mode, that's the mode when the traffic signals take influence on lane-traffic. This is when a tram appears (2.), or when the emergency vehicles need priority (3.) or when a pedestrian pushes the crossing's button (4.). Please note this has nothing to do with the service_times of a traffic signal (often off at night)! It's only about whether it "sleeps" during the day or not and how it takes influcence on lane-traffic.
So, my proposed tags for these special kinds of traffic lights are:
- traffic_signals:standby_mode=* for describing what kind of standy-mode the traffic light has (if there is none, leave this tag away, and note it's only for the "special" kinds of traffic lights) and
- traffic_signals:influencing_mode=* for describing how the traffic light takes influence on lane-traffic (default is that it takes influence by changing to red, so this tag is only needed if the influecing-mode is not changing to red, but flashing yellow or something else).
Proposed values
For the standby-mode of a special traffic signal:
- traffic_signals:standby_mode=off - if the traffic signal is regularly/by default "off" during the day and only activated on demand.
- traffic_signals:standby_mode=continuous_green - if the traffic signal is regularly/by default "green" during the day and changes the light only on demand.
- traffic_signals:standby_mode=blinking_yellow - if the traffic signal is regularly/by default blinking "yellow"/"amber" during the day but on demand, which appears at some times regularly, it changes the light (to red). So note "blinking_yellow" is the standby-mode here, not the way how the signal influences the lane-traffic.
For the influencing-mode of a special traffic signal:
Please note that traffic_signals:standby_mode=none and traffic_signals:influencing_mode=solid_red are mentioned here,but not really proposed, because it has to be assumed that they are default, so these should not be tagged.
Examples
| Image | Description | Tagging |
|---|---|---|
| Tagging different configurations of traffic lights for pedestrian crossings without intersection | ||
| A traffic signal for lane-traffic that is controlling only a pedestrian crossing. Steady green at normal times, until a pedestrian pushes the button of the related highway=crossing. | highway=traffic_signals
traffic_signals=crossing_only traffic_signals:standby_mode=continuous_green (Note that traffic_signals:influcening_mode=solid_red is default and should not be tagged). | |
| A traffic signal for lane-traffic that is controlling only a pedestrian crossing. Off at normal times, until a pedestrian pushes the button of the related highway=crossing. | highway=traffic_signals
traffic_signals=crossing_only
traffic_signals:standby_mode=off | |
| A traffic signal for lane-traffic that is controlling only a pedestrian crossing. It's a crossing with amber flasing lights - when a pedestrian wants to cross, he pushes a button and drivers get a warning by amber flashing lights instead of a solid red light. | highway=traffic_signals
traffic_signals=crossing_only traffic_signals:standby_mode=off traffic_signals:influencing_mode=blinking_yellow |
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