[Talk-us] access=destination vs access=private

Greg Troxel gdt at ir.bbn.com
Sat Sep 10 00:55:11 BST 2011

  Do you think it makes more sense to tag the apartment complexes as
  access=destination or access=private? The complexes are not usually private.
  I can drive into them without a key card (usually); I shouldn't be using
  them as a through street, but they are permitted for use if my destination
  is on that complex street. For OpenTripPlanner, access=destination is
  permitted. Should we permit routing on access=private or change the tags?

There are two issues here:

  1) semantics of laws in the UK applied to the US, in terms of

  2) how can a router use access=private without a side database of
  which users have permission to use which roads?

1) access=destination

As I understand it, the access is tag is fundamentally about what a
member of a public can do by right, and is tightly linked to British
concepts of public rights of way.  This maps relatively well to public
ways in the US, and even to private ways (to which as far as I can tell
the public has a right of access).  In England there are apaprently
streets where one only has a right of access if one is traveling
someplace properly accessed via that street, and I am unaware of this
concept having a broad counterpart in american law.

In the US, we have a lot of private driveways (not "private ways")
leading to houses or businesses, and we have a lot of parking lots that
are privately owned and associated with businesses.  "Everybody knows"
that it's 100% ok to use those driveways if you are (properly) going to
a house/business served by it, and that it's 100% ok to park in a lot
that serves a business if you are going to that business.  But people
have no legal right to demand access; they are licensees or invitees on
that property, and the owner can tell them to leave at any time.

Thus, many people (including me) have repurposed access=destination to
label places where "it's socially 100% ok to use the
road/driveway/parking-lot if you have a related purpose".
Others have used access=customer for the same meaning, to keep it
separate from access=destination.

2) If there access=private, I take that to mean: you could physically
use this, but it's just plain not allowed.

To have a router use access=private ways/etc., you really need a way to
know who is allowed to use which ways.  For emergency=yes, that's
perhaps separate from access=private, but for individuals with differing
permissions, I don't see any way to succeed except to to model the
entire set of "joey can use this road" facts.

Given your situation, it seems like expecting access=destination is the
right answer.  access=private really means "unless you specifically have
been given permission, you should not be on this road".

There's a fine line; I know of a condo complex where there's a gate with
a code, and as an invitee I have the code.  So I could argue that it's
access=private, and that's arguably right.  But, from the point of view
of making the map database useful, routing over that access=private
seems better than not - it makes the situation that invittees with the
code get good routing, and those without codes do not, rather than the
reverse.  Because those with codes are far more likely to be there, that
seems socially optimal.    And a gate should be modeled as a gate;
that's not really the point.

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