Changeset: 34368161
Roads in this area are never used to travel westward from Colerne, Chippenham, etc. The nearby Fosse Way is used to travel to Bath, not these lanes! SatNav apps (Navmii) seem to prefer these roads to the superior Bannerdown residential road to B'easton.
Closed by RFaith
Tags
created_by | iD 1.7.4 |
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host | https://www.openstreetmap.org/id |
imagery_used | Bing |
locale | en-GB |
Discussion
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Comment from ndm
45 mph seems an odd number for maxspeed -- most roadsigns seem to be either 40/50 mph?
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Comment from RFaith
True - it isn't a posted limit, but a personal assessment of how safe it would be at different speeds on this road. 50 is too fast in many places, 40 too slow in others. Motorbikes could go faster but for the surface, which limits bikes. It is an attempt to average the speed you'd manage on this road. To be routed through these lanes when travelling Colerne-Bath is crazy, and it seems that classifying the lanes effectively as C-roads (national speed limit) overstates what they are - rural lanes. It would be better in parts to classify them as residential (as they are at Mill Lane in Box). Going back to Colerne-Bath, the residential road into Batheaston is infinitely preferable to a backtracking detour through lanes. Since this data is a staple of community satnav applications, describing these lanes as a preferable (60-70 mph) alternative to a 30mph direct route is way off-base. The description needs to more accurately describe what these lanes are really like. As a local, my reaction to apps like Navmii and Osmand choosing these lanes in preference to a faster route (even when limited to 30 mph in one section) was incredulity, and part of the problem is one of classification. We can intellectually argue that they are roads of a particular type, but practically, they just aren't! Ironically some of these roads are a little narrower these days because HGVs have been using them and chewing away the edges - and they were there because a satnav told them it was okay! Road Hill down to Ashley is a far inferior road to Bannerdown to Batheaston - they may notionally be the same "sort" of road, but in real terms they are very different (Bannerdown is wide enough to have HGVs pass each other at speed, Road Hill definitely isn't). Of course we're often able to "drive" these routes in Google Streetview and see for ourselves what they're really like!
Sorry for the lengthy and probably repetitive response, but bearing in mind the use to which these maps are put, it seems there needs to be a mechanism to disincentivise routings based on them - one that reflects the reality of using these roads. I'm new to this project and think it is a wonderful effort, and arguably how satnav applications use the data is their business, not OpenStreetMap's. Then again I defy anyone to drive at the notional max speed for Mill Lane in Box!
Suffice to say that a local travelling between Colerne and Bath would be scratching their heads if told to route through Ashley (barring road closures, at least!).
As a general note, maps like these might benefit from "environmental" factors being worked in, not only actual-vs-posted speed limits, but the existence of traffic calming (already done, I think) but also on-street parking.
If there's a better way to make Road Hill reflect its non-whitelined reality (such as making the classification vary more frequently along its length) that might serve the purpose.
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Comment from SomeoneElse
Hello RFaith, welcome to OpenStreetMap!
For info, the "maxspeed" tag is used for the actual posted limit. Where there's an advisory (such as green signs for school areas) you can use "maxspeed:advisory" for those. See http://wiki.openstreetmap.org/wiki/Key:maxspeed#Related_keys , http://wiki.openstreetmap.org/wiki/Key:maxspeed:advisory and http://wiki.openstreetmap.org/wiki/Key:maxspeed:advisory in the wiki for a bit more information. Routers are entirely free to use any / all of these tags when deciding how to route traffic. http://taginfo.openstreetmap.org/search?q=maxspeed shows how often each are used in practice.
Cheers,
Andy -
Comment from RFaith
Hi Andy -
I had another look at it this morning and realised that one of the roads listed as Tertiary in in fact a single-track access road to farms that also just happens to lead almost directly to the A4, which might explain why satnavs are so enthusiastic about it as a viable alternative (drive it in Google streetview and you'll get the idea!). I made it "unclassified" since that description is closest to what the road actually is (single-track with passing places, all but the segment closest to the A4, where it becomes two-way again).
If I left the limit posted, I'll remove it ASAP, since it doesn't reflect signage (or indeed the speed some people drive that road if the little patches of glass are anything to go by).
Thanks for your understanding of a novice!
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Comment from SomeoneElse
Thanks for fixing (and sorry it took so long to reply!).
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