[Talk-GB] Modal Filters and Low Traffic Neighbourhoods

[Robert Skedgell]

A few random and thoughts on this...

I wonder if there could be a case for using a relation (network?) for
the residential streets within an LTN?

There's a (currently undocumented) traffic_regulation_order=* tag used
by Robert Whittaker's PRoW tool which might be worth using on a new
restriction and/or relation. This could be particularly useful if a link
to the TRO published in The Gazette as it's OGLv3.

If the modal filter etc. is the result of an Experimental Traffic Order,
using lifecycle prefix tags like was:* may be a good idea so that the
previous situation can be restored easily if/when the TRO is revoked or
expires (before the paint on the road markings is dry for measures in
Wandsworth, Redbridge, or RBKC).

On 10/04/2021 10:12, SK53 wrote:
> I've mapped a few in the way you describe going back 6 or more years
> ago. An example on Mapillary here
> <https://www.mapillary.com/app/?focus=photo&lat=52.968716&lng=-1.1628939999999999&z=17&pKey=-g91IVVyLUSA0vtjARyCfw>.
> These have a narrow cycle 'gutter' and a much broader area with 'bumpy
> paving' to provide a fire path for emergency vehicles. The
> RantyhighwayMan blog has a good pos
> <https://therantyhighwayman.blogspot.com/2016/12/filtered-permeability-vs-necessary.html>t
> on a wide range of different designs. I think I've tagged these with
> fire_path=yes, as many are signed as such, but perhaps a more explicit
> tag to indicate that these are modal filters would not come amiss (e.g.,
> as a type of cycleway).
> 
> For filtering out these short sections in overpass you could use length
> : way["highway"="cycleway"])(if:length() > 20){{bbox}} although this
> would cut out short sections of other cycleways & the cutoff was rather
> higher than I expected (i.e., over 10 m).
> 
> Jerry
> 
> On Sat, 10 Apr 2021 at 09:07, Steven Hirschorn
> <steven.hirschorn at gmail.com <mailto:steven.hirschorn at gmail.com>> wrote:
> 
>     Hi All,
> 
>     Sorry, long email as there's a lot of complications here that I've
>     been wondering about for a few months. I did a Google Search of the
>     archive and I don't think this has been asked before. Another
>     volunteer and I have been updating OpenStreetMap to include the new
>     modal filters introduced as part of the government's active travel
>     policy.
> 
>     If you want to see what the ones I've been mapping look like today
>     in real life, I've added imagery to Mapillary, and there's an
>     example here:
>     https://www.mapillary.com/app/?lat=51.50207919997222&lng=-0.32299659999999997&z=17&pKey=n99sCMMhsDCVfS8jBIuNQE&focus=photo
>     <https://www.mapillary.com/app/?lat=51.50207919997222&lng=-0.32299659999999997&z=17&pKey=n99sCMMhsDCVfS8jBIuNQE&focus=photo>
> 
>     I wanted to get advice on the best way to map them? The task is
>     partly complicated because in Ealing many of them have been
>     implemented diagonally across junctions, turning them effectively
>     into turn restrictions. When originally installed, they had a
>     removable bollard in the middle, but this has been permanently
>     removed to facilitate better emergency services access and to allow
>     disabled driver (blue badge) and a small number of other exemptions.
>     They are now mostly enforced by ANPR cameras.
> 
>     Generally, the way people have mapped them is to split the roads at
>     the crossroads, joining them to make two corners highlighting the
>     turns, and then adding a highway=cycleway in between to facilitate
>     routing. Sometimes tags have been added for emergency=yes,
>     horse=yes, motor_vehicle=no, foot=yes, and I'm not completely clear
>     which ones are superfluous.
> 
>     I know we don't tag for the renderer, but one aspect I like in the
>     way others have mapped them is that it makes the OpenStreetMap
>     default rendering really clear about where the filters are and which
>     route a driver would need to take to get to any address in the LTN,
>     something Google and here.com <http://here.com> (for example) aren't
>     coping with very well at all. It also worked very well for the
>     routers and OpenStreetMap based routers have been correct from day
>     one unlike Google which still sometimes offers routes that are
>     illegal (try finding a logical way to submit a diagonal filter to
>     Google Maps!)
> 
>     What I don't like is that if I now do an Overpass query for
>     cycleways, there are lots of 2 metre long "cycleways" dotted all
>     over the map. Also I'm not sure if highway=cycleway & emergency=yes
>     (because ambulances and fire engines are allowed to pass) is a valid
>     combination? And is there a way of mapping that there are exemptions
>     for blue badge holders? I know a lot of this is moot as the
>     ambulance service use old sat navs that AFAIK aren't aware of
>     emergency service exemptions, but the principle of having an
>     emergency service route option as well as "car", "bicycle" and
>     "foot" seems like a brilliant concept)
> 
>     They could alternatively be mapped as turn restrictions, but I don't
>     think it's possible to make an exception for bikes, and turn
>     restrictions wouldn't be visible on the map rendering.
> 
>     I noticed that a user, MacLondon, has added an extra tag
>     "note:covid19" tags (with value "Experimental modal filter") which
>     makes it a bit easier to query for the new filters if anyone wants
>     to look for more.
> 
>     What do other volunteers think?
> 
>     Steven