[Talk-us] Trunk

Greg Troxel gdt at lexort.com
Sat Oct 14 00:40:51 UTC 2017


Dave Swarthout <daveswarthout at gmail.com> writes:

>>I don't think "important connecting role in the long distance road
>>network" should have anything to do with it.   A regular US highway that
>>is not divided, grade-separated, mostly limited access is still a key
>>interconnecting road, and it's squarely "primary".  Most of US 20 is
>>like this, as I understand it, and all or almost all of the parts I've
>>driven on (MA, WY) are like that.
>
> I don't really have a stake in the outcome of this discussion but wish to
> again point out that Alaska is a state where "trunk" has been used to
> designate highways that are ordinarily classified as primary but because
> they are in a state with so few roads and in which they are the "only"
> connectors between towns, have been tagged trunk highways. They are

I see where you are coming from, but I don't agree.  It's perfectly
sensible for roads that are primary or even secondary to be the only
roads.  In the US, primary is more or less aligned with US highway or
road of equal importance (such as MA 2 that I talk about a lot).

> high-speed, 65 mph in most cases, or I should say, in most sections, but
> have driveways, intersections, and when passing through towns, lower speed
> limits, traffic signals, etc.

If they are not divided, then that sounds like a rural primary.  I've
seen lots of roads in West Texas (maybe the closest thing to AK in the
lower 48) that are one lane each way, yellow line, ranch driveways and
occasional intersections, posted 65 mph.   I don't see why this would be
trunk even if it's the only way to get someplace.

My view is that there is no need for any roads labeled trunk to exist,
if they aren't physically trunky.   I don't see any notion "you must be
able to get to a town with population > X  via a road which is >= trunk".

> Just an observation on an edge case that is moderately important in our
> immense and 99% rural state.

(I'm really not trying to give you a hard time here; I'm trying to have
us ferret out what's necessary for tags we don't have now, in order to
do better rendering and routing.)

Can you explain what your goal/desire is for these non-divided highways
to be labeled trunk?  Is it about a small-scale render showing them,
when if they are primary, Alaska looks empty when it shouldn't?  Some
sense of hierarchical views of road networks?  Something else?

I get it that I need to be at z4 to see the whole state, and that the
renders built for other places are really struggling.

Massachusetts, on the other hand, can be seen (same window) at z8, so
we're talking a factor of 256.  Interestingly, at z4, which is what I
need for CONUS, there are no roads rendered.  But, doing it by hand, I'd
show most of the main NS/EW Interstates even at that scale.  At z5, I
think all interstates show up, and that may be a bit much.   My point
here I guess is that the "what shows when" needs some love for CONUS
too; it's just more obvious in AK because we are always zoomed in more
becauase our states are so small ;-)

Looking at AK 3, I see it's marked trunk.  I rode on this a few years
ago, and my memory is fuzzy, but it felt not divided, not much on the
sides but not controlled, and usually one lane each way.  That feels
like primary, even though it is arguably one of a few roads that vie for
most important.

Here, I think the thing to do is to change rendering so that there is
some notion of key long distance route and render some of those even at
z4 or maybe even z3.  We're trying to get algorithms to do what
cartographers used to do, deciding to draw roads based on whether it
makes sense to see them at a given scale.  You know far better than me
(who has only been there 3 days) but I would guess "AK 3 should show up
at z4" is a sensible statement.

Greg
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