Designating "Traffic Lights" vs "Traffic Signal"

Hi All again… I noticed some [Traffic Lights / Traffic Signal] designation on OSM showing a little icon with vertical [Red / YELLOW / Green] that looks like a hanging traffic light. I’m from USA and I think Traffic Lights & Traffic Signal loosely refer to the same thing. However “personally” I consider Traffic Lights to be like the [Red / YELLOW / Green] icon. 3 lights control device. Some road intersections have a Single [RED] Flashing light on all 4 sides or a [YELLOW] flashing light on the 90 degree positions.

On OSM I’ve seen these control lights called “Traffic Lights” or “Traffic Signals” What is the preferred designation… and should i change the designation on the map from Traffic Signal to Traffic Lights or vice versa according to my lose definition above?

Thanks for your input… :slight_smile:

The typical red-amber-green lights and flashing ambers/reds should both be tagged with highway=traffic_signal. Further specificity can be made by tagging the flashing amber/red setups with traffic_signal=blinker. (While the typical three-colour signals are just “traffic_signals=signal”.)

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These are intersection control beacons. Indeed, highway=traffic_signals traffic_signals=blinker is how most of them have been mapped so far. (In iD, you’d use the Traffic Signals preset and set the Type to blinker.) However, I think it’s probably time to revisit this tagging combination, because it has multiple problems:

  • Functionally speaking, the beacon merely supplements a two- or four-way stop with required stop signs. A routing engine should treat the intersection just like a stop-controlled intersection for the purposes of timing and counting intersections (“At the next stop sign…”). A renderer should mark these intersections with :stop_sign: rather than :vertical_traffic_light:, reflecting the primary equipment.
  • At a two-way stop, the road that has the right of way sees an amber flashing beacon, but this is just a warning light, no different than the flashing beacon atop a warning sign, which is most often tagged as flashing_lights=yes.
  • highway=traffic_signals traffic_signals=blinker is easily confused with highway=traffic_signals traffic_signals=blink_mode, for when a :vertical_traffic_light: traffic light is temporarily on blinking mode.

Personally, I’ve begun using highway=stop stop=all traffic_signals=blinker on all-way stops and highway=stop stop=minor traffic_signals=blinker at the stop lines on two-way stops. However, it isn’t unreasonable to use highway=traffic_signals traffic_signals=blinker for now if you’re OK with it potentially needing to be updated with new tagging in the future.


Thanks hoserab & Minh_Nguyen… !!!

I will take your leads and use the convention “Traffic_Signals” and not use Traffic_Lights should the need present in my area. Also your points all makes sense. The single Blinking Red or Amber etc… The first is just an aide to the physical STOP sign… and the latter flashing Amber is just a warning to alert drivers without stopping traffic flow. The various kinds of “Signals”, flashing, not flashing, Green Arrow, no arrow, Red / Amber / Green at certain hours and just flashing at other hours. It all can be quite confusing and complex.

THANK You BOTH for shedding light on this potentially impossible subject.
For now I think I’ll stick with adding and editing Speed Limits. At least that’s a concept that has only a few variables.

Thanks again for enlightening me.
Best wishes to you Both… :slight_smile:

Someone (supposedly experienced) has been going around here splitting single node traffic_signals at simple crossings into each single light location and then not tagging the traffic_signals:direction, no tags whether button operated, vibrator or beep on foot crossings, nada.There’s also signs that say to respect the stop spots when TSs are off or in blinker mode. Absent. Why on earth do that and not bother with everything else that goes with this is beyond me.

(We have a few which were set to permanent blink mode as operating them caused catharsis… drivers fill every little gap between cars, traffic lights don’t. Traffic lights with sensing in the pavement… never heard off, but our new trolley route is going to detect buses coming on so that lights will spring in the right arrangement for speedy passage, flabbergasted, were it not the route has been reading since 5 years, they failed to put the right technology in so now)

rant end