[OSM-talk] Should Bridges be independent of their ways?

[Anthony]

On Sun, Sep 20, 2009 at 2:19 PM, John Smith <deltafoxtrot256 at gmail.com>wrote:

> 2009/9/21 Anthony <osm at inbox.org>:
> > In general, the more important question than whether or not you can
> U-turn
> > is whether or not you can cross the center line in order to make a left
> > (right if you drive on the other side) turn.  I believe the law in most
> US
> > jurisdictions is that this is allowed when physically possible unless
> there
> > is a painted median (double double yellow lines), traffic cones, etc.  In
> > the case of a painted median (double double yellow lines), if this is
> > represented as a single way, that is incorrect and should be fixed.  In
> the
> > US, there is probably a lot of this, because we imported so much from
> Tiger,
> > which represents pretty much everything except major highways as single
> ways
> > (and is a significant area needing cleanup).  Outside the US, I just
> don't
> > know the laws.
>
> Assumptions are dangerous things, I suppose this is why so many
> tourists have accidents because they assume the whole world is just
> like where they are from.
>

I am not assuming this, however.  In fact, I *specifically* pointed out the
fact that I was *not* assuming it.

Mapping ways should follow the legal paths of travel, not the existence or
non-existence of concrete.  If concrete is the only form of legal barrier,
then fine, concrete can determine how we map.  But if a painted median is
legally equivalent to a concrete barrier, we should map the two situations
equivalently.  Thus, at least in Florida, simply looking for concrete is not
sufficient.  (Yes, this is my opinion, but it is an opinion which I have
supported by many previous statements.)

> Even if there is a concrete barrier or other form of barrier that would
> > prevent a car crossing?  Why are bridges different?
>
> Usually because bridges narrow things to make it cheaper to cross a
> river etc, however my point still stands a way is a physical thing, if
> there is only one physical thing then that's all that should be mapped
> and lanes should be tagged independently of the way.
>

But if there is a concrete barrier in place, you agree we might have two
ways going over one bridge.  So all this stuff about mapping individual
lanes is off-topic.
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