[Talk-us] US highway classification

[Anthony]

On Sat, May 28, 2011 at 3:39 PM, Nathan Mills <nathan at nwacg.net> wrote:
> On Sat, 28 May 2011 15:19:03 -0400, Anthony wrote:
>
>> In my experience the difference between primary and trunk is generally
>> very minor, to the point where I'm not sure there'd be any advantage
>> at all in a router using it as a hint.
>>
>> But maybe that's just because the places where I use OSM are mapped wrong.
>
> Using NE2's criteria, trunk is not really any different from a routing
> standpoint than primary. Using mine, trunk is something that would be
> primary if it weren't a physically better sort of road, so should be
> preferred over a nearby primary if the distances are similar. I'm harping on
> physical characteristics for this one particular tag because I think without
> that as a differentiator, it's basically useless fluff we shouldn't be using
> at all because primary already covers that usage.

For routing purposes, I think trunk is destined to be useless fluff
(even if your ideas about how to tag it so it isn't were perfect,
you'd still have the problem of convincing the mappers to use it).
For rendering purposes, I think there's room for a road, which isn't a
motorway, which shows up at least one zoom higher (less zoomed) than
primary.  I suppose that's what trunk is.

In theory maybe the rendering software could somehow figure that out
itself, but I'm not sure how feasible that is right this moment.