What is the consensus is on using junction=circular is in the UK, if there is any?
I’m asking because the right-of-way-based distinction from junction=roundabout is meaningful for signalized things-called-roundabouts, as they’re currently documented in the wiki.
I favour the documented meaning for both junction types, and use I the newer tag in my area along with others for some junctions signed and named “roundabout”: chiefly, ones with traffic signals on them.
However, there does not seem to be any consensus in existing data, and just this afternoon, some coincidentally timed mass edits from another mapper; we find we disagree in the changeset comment threads, and I won’t link here. I’m choosing to disengage from a smaller, unrelated, focused tagging exercise and ask here, since the other mapper’s doing the exact opposite from me, and edit wars are unproductive.
Conversely, Road signs in the United Kingdom only stipulates junction=roundabout, and ignores things with traffic lights on them. Maybe that’s a historical accident, since that tag’s just older. I think that junction=circular was introduced to address goey-aroundy-junctions of any common name which don’t give traffic on them absolutely uncontested priority. I got from the tagging mailing list thread an idea that junction=roundaboutalways connoted right of way, being originally derived from UK road law rather than plain/vague speech.
So, er, what do other UK people actually do in practice? And what should we do?
I don’t know about the legal side, but from common experience, I’m sure most people think of most of the circular junctions with traffic lights as being roundabouts. It’s possible they’re even still signed as such, which might mean they’re legally still roundabouts.
On the other hand, there are certainly some goey-aroundy-junctions that don’t appear as normal roundabouts, whether or not they have traffic lights as well.
The Highway Code Rule 185 contains “give priority to traffic approaching from your right, unless directed otherwise by signs, road markings or traffic lights” and “check whether road markings allow you to enter the roundabout without giving way. If so, proceed, but still look to the right before joining” which suggests that it’s possible to have things that are legally roundabouts but don’t follow the usual give way rules. (Though that may be an over-simplification for readers.)
I think roundabouts with traffic lights should be tagged as roundabouts. This is because the population of the UK consider them roundabouts. Also, if the traffic lights were to not be working they would be treated as roundabouts without traffic lights. It is the suggestion on the openstreetmap wiki that roundabouts with traffic lights be tagged as roundabouts.
In my experience roundabouts with traffic lights use the exact same signage symbols as roundabouts without traffic lights. The signs say they are roundabouts. People expect them to be called roundabouts.
There are junctions where the route around the island has a give way line and those are not roundabouts but they are not common in the UK.
Another possible issue is if the maps are used with a navigation system and these junctions are not tagged as roundabouts and the navigation prompts make no mention of roundabouts then people could be confused with the instructions as they think of the junctions as roundabouts. Instead of being prompted to take the third exit (for example) you are directed to keep bearing right and then turn left at the appropriate exit. That is not expected behaviour. I have actually experienced this.
A consensus on the tagging schema for these junctions would indeed be useful.
There are specifically no markings on some of the lanes on the “roundabout”, but there are on the slip roads leading up to, and away from it.
e.g. one of the slip-roads leading from the dual carriageway, both lane 1 and 2 are “ahead” lanes and assume you will stay on the roundabout, with lane 3 being a right turn. you could turn left and rejoin the dual carriageway from lane 1, but it isn’t required.
However, people on the roundabout waiting to join the dual carriageway in the same area, lane 1 you MUST join the dual carriageway, lane 2 is an optional ahead (staying on the roundabout) or left to join the main road, and lane 3 takes you into town… with the option to rejoin the dual carriageway in the opposite direction.
To me, this is not a roundabout. Lane priorities change depending on the phase of the lights, and where you have come from. I don’t know of any non-controlled roundabouts that do this.
Specifically this roundabout, if you “mess up” and end up missing your exit, it becomes very confusing which lane you should be in to fix your mistake, unlike a roundabout where you would move right, and stay there until you got back to where you were originally.
That might be a pragmatic distinction. I would agree that roundabouts with traffic signals that are only used at peak times should be tagged as roundabouts.
There are other, larger, more complex roundabouts which could not function without traffic lights!
I imagine this would depend on the router. It is not obvious when/if routers should treat a complex circular junctions a “simple roundabout”. I think of junction=circular as an indication that more detailed instructions might be needed to successfully navigate the junction.
There are other, larger, more complex roundabouts which could not function without traffic lights!
Yes I know its google… sorry… but a good example are these two images of the same location on the same junction. These are exactly what you said, they would not function if the lights were not working.
This image, traffic was waiting on the “roundabout” and even vehicles in lane 2 are turning right:
This junction does not follow the rules of a roundabout, who has priority, who should give way. Should the lights fail, cars from one direction would be at risk of driving into the side of cars from another.
wongataa:
Also, if the traffic lights were to not be working they would be
treated as roundabouts without traffic lights.
That might be a pragmatic distinction. I would agree that roundabouts
with traffic signals that are only used at peak times should be
tagged as roundabouts.
There are other, larger, more complex roundabouts which could not
function without traffic lights!
wongataa:
Another possible issue is if the maps are used with a navigation
system and these junctions are not tagged as roundabouts and the
navigation prompts make no mention of roundabouts then people could
be confused with the instructions as they think of the junctions as
roundabouts.
I imagine this would depend on the router. It is not obvious when/if
routers should treat a complex circular junctions a “simple
roundabout”. I think of junction=circular as an indication that more
detailed instructions might be needed to successfully navigate the
junction.
OSMand treats them exactly the same a roundabouts.
In most case in the UK I feel the circular tag is wrong, they are still
legally and if you ask a normal bloke in a pub what they are they would
answer roundabouts.
There is nearly always one entry point which is not traffic light
controlled and follows normal roundabout rules.
I agree that some of these junctions could well be better tagged as circular instead of roundabouts. There are many more that would bet better tagged as roundabouts.
There doesn’t seem to be any signage preventing a U-turn approaching from E, but you would have to be quite brave to try this! This junction is described as a roundabout, but does seem better described as a circular junction (although it is not even obvious which ring to label).
It would be useful to understand whether any data consumers make a distinction. It not, the discussion is somewhat academic.
The annoyingly reliable “bloke in the pub” argument is unfortunately quite a strong one here. I don’t know of any junctions I would call “circular” that most people wouldn’t call a roundabout.
BUT I do know, every circular junction, my friends from the pub would call “the worst roundabout ever, the lines never make any sense, and one day there will be a bad crash”.
Because… It’s not really a roundabout.
I think though, most of us would agree, a normal roundabout, with normal rules on a roundabout… that happens to have lights to control who has priority, would still count as a “roundabout” in the UK.
Maybe the discussion should be about if the lights control where people go, not who has priority?
Here’s one (but it’s a low priority example on a university campus). The traffic on the “roundabout” has to give way to traffic joining the “roundabout” for one specific entry. All other entries obey the usual give way rules.
It’s currently tagged as junction=circular and I think that’s probably appropriate.
There’s a roundabout near me where the four main entrance roads are traffic-light controlled (with corresponding lights on the roundabout just before them), but two other entrances aren’t: https://www.openstreetmap.org/#map=18/52.603149/1.224493
The rule seems to be up to 4 entry points will be controlled by lights. The 5th or more, which will be the most minor will be standard roundabout control
OSMand treats them the same as roundabouts and gives standard nth exit instructions.
Don’t remember what it was but when I was using sailfish os, a native app gave turn left as you entered, turn right to go around and turn left to leave. Very confusing.
