[Accessibility] Mapping complex road junctions with pedestrian crossings

[Barbeau, Sean]

Hi all,
We've looked at general accessibility issues in OpenTripPlanner (OTP) and OpenStreetMap as part of a research project at USF (http://www.locationaware.usf.edu/ongoing-research/projects/open-transit-data/), and we would strongly suggest that micro-mapping of intersections in OpenStreetMap be done according to the "Sidewalk as a separate way" (http://wiki.openstreetmap.org/wiki/Proposed_features/Sidewalk_as_separate_way) convention that Flaimo mentions.  This convention seems like the best method to fully support detailed accessibility routing for intersections that aren't perfectly symmetrical.

There are two distinct categories for intersection mapping:  implicit, in which it is assumed that an intersection is perfectly symmetrical (e.g., curb cuts/tactile strips are universal to all sidewalk/road) unless exceptions are stated, and explicit, in which the detail for the entire intersection is coded.  For dense, well-established pedestrian environments like New York or Washington, D.C., the implicit code might be preferred due to less effort by OSM users when coding data.  However, for suburban/rural areas in which pedestrian infrastructure isn't as dense and sidewalks aren't universal the explicit coding seems to be the preferred method.  There is still an open area of work for how routing is handled in transitions between implicitly and explicitly coded areas, and to my knowledge OpenTripPlanner hasn't tackled this yet.  We've coded OSM data according to explicit "Sidewalk as a separate way" method and tested it in OTP on the USF campus in our OTP deployment (http://opentripplanner.usf.edu/), and this method works best for our suburban campus.

More details about "Sidewalk as a separate way" OSM coding in context of OpenTripPlanner is available in a presentation here (http://goo.gl/1xltp) starting on slide 6, and in a final report here (http://goo.gl/k3Uiy) starting on page 47.

I should mention that our research team that worked on this is sighted, and we would welcome any additional insight into this problem from anyone with visual impairments, or anyone with differing opinions.

Thanks,
Sean

Sean Barbeau
Research Associate
Center for Urban Transportation Research
University of South Florida

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Today's Topics:

   1. Re: Mapping complex road junctions with pedestrian	crossings
      (Flaimo)


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Message: 1
Date: Sat, 11 Feb 2012 13:21:25 +0100
From: Flaimo <flaimo at gmail.com>
To: accessibility at openstreetmap.org
Subject: Re: [Accessibility] Mapping complex road junctions with
	pedestrian	crossings
Message-ID:
	<CAM9eaZLXBJ+kLGgVg9+B39=6D1=YDgXXCFtORz4r50v_yb4GLg at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8

there already is an approved proposal for footway=crossing/sidewalk which also introduced sloped kerbs:
http://wiki.openstreetmap.org/wiki/Proposed_features/Sidewalk_as_separate_way
. footway=crossing has been used over 16000 times so far; footway=sidewalk 30000 times. i started tagging those, as soon as the proposal was approved. for example at this junction:
http://osm.org/go/0JhM2ot0J--

regards,
flaimo

On Sat, Feb 11, 2012 at 13:00,  <accessibility-request at openstreetmap.org> wrote:
> ------------------------------
>
> Message: 2
> Date: Fri, 10 Feb 2012 14:58:08 +0100
> From: Peter Wendorff <wendorff at uni-paderborn.de>
> To: accessibility at openstreetmap.org
> Subject: Re: [Accessibility] Mapping complex road junctions with ? ? ? 
> ?pedestrian crossings
> Message-ID: <4F352270.1030700 at uni-paderborn.de>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Hi John.
> Welcome on this list.
> I'm sighted too, but working on the Look-and-Listen-Map currently and 
> did my bachelor thesis about navigation for the blind.
> In the thesis I proposed a tagging scheme similar to what you propose here:
> A way cutting the street, where the common nodes are tagged as 
> highway=crossing, crossing=* and a node between the middle node and 
> the "border" node tagged with sloped_curb=* and tactile_paving=*.
> I did not tag the way itself different than any footway, but yes, that 
> may be a good idea.



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