[OSM-talk] [Tagging] - RFC - Motorway_link implies oneway=??

[Alex Mauer]

On 10/3/2008 6:27 AM, Ben Laenen wrote:
> Then read the example on
> http://wiki.openstreetmap.org/index.php/Tag:highway=motorway_link once.
> It says: "The green way in this example can then be a simple junction
> withhighway=motorway_link without the oneway tag, as it is supposed to
> be used in both directions."
>
> When you read that, you don't assume there's no implicated oneway value.
> It says that by default it's oneway=no like with any other road.

Fair enough, though as far as I know it's never stated anywhere else 
that oneway=no is the default.  Certainly it's not on the Key:highway or 
the Key:oneway page.

> Note that the "implies oneway=yes" in the right column wasn't added on
> the page until June this year. Only from that point onwards the page
> started contradicting itself. Before that it clearly said oneway=no is
> implied.

Only since October 2007.  So there's a seven month window in which it 
could have been taken to be oneway=no by default, though that was never 
stated clearly.

> Hence the only option is to revisit all motorway links that don't have a
> oneway value and add it. After that we may have a oneway=yes
> implication.

It's really not the only option.  We can also just accept that there are 
a few motorway_link tags that are wrong.  Which there probably will be 
no matter what.  I'd much rather have sane defaults and a slight 
inaccuracy then have to deal with insane defaults forever just because 
of a short window created by someone who made some bad assumptions.

-Alex Mauer "hawke".