Re: [Talk-GB] Motorway junctions where the slow lane seperates from the through lanes
Hi I would suggest that the motorway should not be split until the point where the two halves physically diverge; instead, where there's a drop lane, use turn:lanes and destination:lanes tags to indicatethe presence of the drop lane. My reasoning for this: - firstly, there's no physical separation between the drop lane and the main line of the motorway, and it's still physically and legally possible to change between the two, and - secondly, splitting a motorway based on different lanes having different destinations sets an awkward pattern, which taken to extremes means we end up splitting roads all over the place based on lane markings. Sometimes that's necessary to make routing work sensibly through complex junctions, but I'd argue that this isn't one of those cases. Best illustrated with examples: Drop lane starts here. Before this point, a single way with lanes=3. After this point, still a single way, with lanes=3, turn:lanes=slight_left|through|through : https://www.mapillary.com/app/?pKey=v4H-uhxh9QQYjzL1b_BNMg=photo The drop lane then runs for 300 metres, where there's no physical (or legal) barrier between the lanes, so still a single way with lanes=3, turn:lanes=slight_left|through|through : https://www.mapillary.com/app/?pKey=S-dGYQdsR7olODRufbB5bg=photo Then the actual split, where first there's a legal barrier (solid white paint), then a physical one (grass, barrier, trees, hillside, etc): https://www.mapillary.com/app/?pKey=1WY5HbP5K-vpUnAT0voYGw=photo It's here where I'd suggest we'd split into highway=motorway_link, lanes=1 (lanes=2 shortly thereafter), and highway=motorway, lanes=2, with a shortish Y-shaped transition to make it look sensible. Of course, at this point the main line of the motorway loses the turn:lanes tag, and you can then add turn:lanes tags to the slip road as it widens out for the roundabout at the end. The middle point of the Y (and not the start of the drop lane) carries the highway=motorway_junction and associated tags. You could also add destination:lanes tags to label up the signed destinations, and destination:ref:lanes=A4174|M32|M32. Incidentally, for me, /this/ is the sort of situation justifying separate, parallel ways on a motorway: https://www.mapillary.com/app/?pKey=AL0RC-DyWe27PMQEAS1uZA=photo TL;DR? Don't split based on lane markings, it's not a 300-metre-long physically separate way, it's just a lane with a different destination. Instead use turn:lanes, destination:lanes and destination:ref:lanes tags to indicate the drop lane. Cheers, Paul ("southglos") ___ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Motorway junctions where the slow lane seperates from the through lanes
This is a changeset that is under discussion: https://www.openstreetmap.org/changeset/79260663#map=16/51.5089/-2.5232 The disagreement is that there may be the start of an "exit lane", but there is no physical separation where the junction has now been modified -- see the changeset dicsussion for background info. Local mappers would prefer that the junction were to be split where there is a physical, rather than a logical separation, https://wiki.openstreetmap.org/wiki/Editing_Standards_and_Conventions#Divided_highways Cheers, Neil ___ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Motorway junctions where the slow lane seperates from the through lanes
Have a look at www.openstreetmap.org/changeset/79582073 On my Samsung Tablet I have been using Bing satellite images with the Vespucci editor, but other images also show the road markings quite clearly. From: Ed Loach Sent: 14 January 2020 13:45:34 To: 'Paul Berry' ; 'Mike Parfitt' Cc: talk-gb@openstreetmap.org Subject: RE: [Talk-GB] Motorway junctions where the slow lane seperates from the through lanes See also https://wiki.openstreetmap.org/wiki/Lanes which has some quite good notes on how to map lanes. I suspect this is how OsmAnd knows to give me lane guidance (can’t think how else it could know). I suspect based on that you’d want to begin your new way for the drop lane where the lane splits away from the main carriageway, with an earlier split for lanes=3, turn:lanes=slight_left|through|through with lanes=1 on the new way and lanes=2 on the main way after the split. Ed From: Paul Berry Sent: 14 January 2020 13:15 To: Mike Parfitt Cc: talk-gb@openstreetmap.org Subject: Re: [Talk-GB] Motorway junctions where the slow lane seperates from the through lanes Hi Mike, Interesting points and no easy answer I fear. I think in mapping terms the midlines of each carriageway after the diverge will look more like a upside-down Y and I tend to do a bit of smoothing to make it look less abrupt. I think this is what you're getting at (apologies if not). It's not dissimilar to the situation where a single-carriageway road splits around an island: because the way is drawn as a line—not an area—the carriageway split is always going to look more dramatic drawn that way compared to the smooth continuous reality of what's on the ground. In the situation of a lane drop don't forget to keep track of the lanes= in the keys. It might be easier if you just go ahead and map as you see fit then post the changeset link if you want further commentary. Regards, Paul On Tue, 14 Jan 2020 at 08:26, Mike Parfitt mailto:m_parf...@hotmail.com>> wrote: The technical term is a drop lane. This might later intersect with a roundabout, join with another motorway or primary road etc. Between junctions, a single way for each direction is commonplace. At junctions, there are ways for the through lanes and for traffic exiting and entering the motorway. For example, on a 3-lane motorway with 3 lanes going in one direction and no junction anywhere near, the way would typically be placed along the centre of lane 2. However, when lane 1 is designated as a drop lane, what was being mapped as 1 way needs to split into 2 ways. The question is where ? There are various anticipatory changes in road markings well ahead of the physical separation of the asphalt, together with blue and white signs, some of which precede the first of the changes in road markings. In the case described above, my convention is to pick the start of the shorter dashes between the drop lane (1) and the through lanes (2 and 3). From then onwards, the way for the through lanes is mapped along the longer dashes dividing lanes 2 and 3, while the way for the drop lane is mapped along the centre of lane 1. Others do it differently. See "https://www.gov.uk/government/publications/traffic-signs-manual; from where you can download "Traffic signs manual chapter 5 road markings (2019)" which is a PDF. Page 82 contains figure 7.7 and text documenting drop lane road markings. ___ Talk-GB mailing list Talk-GB@openstreetmap.org<mailto:Talk-GB@openstreetmap.org> https://lists.openstreetmap.org/listinfo/talk-gb ___ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Motorway junctions where the slow lane seperates from the through lanes
See also https://wiki.openstreetmap.org/wiki/Lanes which has some quite good notes on how to map lanes. I suspect this is how OsmAnd knows to give me lane guidance (can’t think how else it could know). I suspect based on that you’d want to begin your new way for the drop lane where the lane splits away from the main carriageway, with an earlier split for lanes=3, turn:lanes=slight_left|through|through with lanes=1 on the new way and lanes=2 on the main way after the split. Ed From: Paul Berry Sent: 14 January 2020 13:15 To: Mike Parfitt Cc: talk-gb@openstreetmap.org Subject: Re: [Talk-GB] Motorway junctions where the slow lane seperates from the through lanes Hi Mike, Interesting points and no easy answer I fear. I think in mapping terms the midlines of each carriageway after the diverge will look more like a upside-down Y and I tend to do a bit of smoothing to make it look less abrupt. I think this is what you're getting at (apologies if not). It's not dissimilar to the situation where a single-carriageway road splits around an island: because the way is drawn as a line—not an area—the carriageway split is always going to look more dramatic drawn that way compared to the smooth continuous reality of what's on the ground. In the situation of a lane drop don't forget to keep track of the lanes= in the keys. It might be easier if you just go ahead and map as you see fit then post the changeset link if you want further commentary. Regards, Paul On Tue, 14 Jan 2020 at 08:26, Mike Parfitt mailto:m_parf...@hotmail.com> > wrote: The technical term is a drop lane. This might later intersect with a roundabout, join with another motorway or primary road etc. Between junctions, a single way for each direction is commonplace. At junctions, there are ways for the through lanes and for traffic exiting and entering the motorway. For example, on a 3-lane motorway with 3 lanes going in one direction and no junction anywhere near, the way would typically be placed along the centre of lane 2. However, when lane 1 is designated as a drop lane, what was being mapped as 1 way needs to split into 2 ways. The question is where ? There are various anticipatory changes in road markings well ahead of the physical separation of the asphalt, together with blue and white signs, some of which precede the first of the changes in road markings. In the case described above, my convention is to pick the start of the shorter dashes between the drop lane (1) and the through lanes (2 and 3). From then onwards, the way for the through lanes is mapped along the longer dashes dividing lanes 2 and 3, while the way for the drop lane is mapped along the centre of lane 1. Others do it differently. See "https://www.gov.uk/government/publications/traffic-signs-manual; from where you can download "Traffic signs manual chapter 5 road markings (2019)" which is a PDF. Page 82 contains figure 7.7 and text documenting drop lane road markings. ___ Talk-GB mailing list Talk-GB@openstreetmap.org <mailto:Talk-GB@openstreetmap.org> https://lists.openstreetmap.org/listinfo/talk-gb ___ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Motorway junctions where the slow lane seperates from the through lanes
Hi Mike, Interesting points and no easy answer I fear. I think in mapping terms the midlines of each carriageway after the diverge will look more like a upside-down Y and I tend to do a bit of smoothing to make it look less abrupt. I think this is what you're getting at (apologies if not). It's not dissimilar to the situation where a single-carriageway road splits around an island: because the way is drawn as a line—not an area—the carriageway split is always going to look more dramatic drawn that way compared to the smooth continuous reality of what's on the ground. In the situation of a lane drop don't forget to keep track of the lanes= in the keys. It might be easier if you just go ahead and map as you see fit then post the changeset link if you want further commentary. Regards, *Paul* On Tue, 14 Jan 2020 at 08:26, Mike Parfitt wrote: > The technical term is a drop lane. This might later intersect with a > roundabout, join with another motorway or primary road etc. Between > junctions, a single way for each direction is commonplace. At junctions, > there are ways for the through lanes and for traffic exiting and entering > the motorway. > > For example, on a 3-lane motorway with 3 lanes going in one direction and > no junction anywhere near, the way would typically be placed along the > centre of lane 2. > > However, when lane 1 is designated as a drop lane, what was being mapped > as 1 way needs to split into 2 ways. > > The question is where ? > > There are various anticipatory changes in road markings well ahead of the > physical separation of the asphalt, together with blue and white signs, > some of which precede the first of the changes in road markings. > > In the case described above, my convention is to pick the start of the > shorter dashes between the drop lane (1) and the through lanes (2 and 3). > From then onwards, the way for the through lanes is mapped along the longer > dashes dividing lanes 2 and 3, while the way for the drop lane is mapped > along the centre of lane 1. > > Others do it differently. > > See "https://www.gov.uk/government/publications/traffic-signs-manual; > from where you can download "Traffic signs manual chapter 5 road markings > (2019)" which is a PDF. Page 82 contains figure 7.7 and text documenting > drop lane road markings. > ___ > Talk-GB mailing list > Talk-GB@openstreetmap.org > https://lists.openstreetmap.org/listinfo/talk-gb > ___ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb
[Talk-GB] Motorway junctions where the slow lane seperates from the through lanes
The technical term is a drop lane. This might later intersect with a roundabout, join with another motorway or primary road etc. Between junctions, a single way for each direction is commonplace. At junctions, there are ways for the through lanes and for traffic exiting and entering the motorway. For example, on a 3-lane motorway with 3 lanes going in one direction and no junction anywhere near, the way would typically be placed along the centre of lane 2. However, when lane 1 is designated as a drop lane, what was being mapped as 1 way needs to split into 2 ways. The question is where ? There are various anticipatory changes in road markings well ahead of the physical separation of the asphalt, together with blue and white signs, some of which precede the first of the changes in road markings. In the case described above, my convention is to pick the start of the shorter dashes between the drop lane (1) and the through lanes (2 and 3). From then onwards, the way for the through lanes is mapped along the longer dashes dividing lanes 2 and 3, while the way for the drop lane is mapped along the centre of lane 1. Others do it differently. See "https://www.gov.uk/government/publications/traffic-signs-manual; from where you can download "Traffic signs manual chapter 5 road markings (2019)" which is a PDF. Page 82 contains figure 7.7 and text documenting drop lane road markings. ___ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb