[Talk-us] [Talk-us-newyork] Highway classification guidelines for New York State

[Minh Nguyen]

Vào lúc 03:03 2021-09-13, Mateusz Konieczny via Talk-us đã viết:
> 
> 
> 
> Sep 13, 2021, 10:43 by 
> minh at nguyen.cincinnati.oh.us:
> 
>     Vào lúc 16:47 2021-09-12, Eric Patrick đã viết:
> 
>         I have a thought regarding trunks in regards to functional
>         classification, and this is going to come from a different
>         viewpoint. Why not make Primary Arterials trunk roads, from a
>         coding standpoint. They're coded lower than a motorway, but
>         higher than everything else. Any GPS system will use the highest
>         coded route, with the fewest penalties, they can get to between
>         points A and B. I understand that in doing this, a lot of
>         downtown areas will look like a sea of red, due to the density
>         of the Primary Arterials within those areas (cue Brian's groan
>         about this).
> 
> 
>     As far as I can tell, no mainstream OSM-based router directly
>     penalizes a road based on its highway=* value per se. If it lacks a
>     maxspeed=* tag and real-time or historical traffic data is
>     unavailable or unsupported, then the router would assume a speed
>     limit based on the highway=* value. From what I've seen, these
>     assumptions are usually wrong for... just about everywhere.
> 
> bicycle-focused and foot-focused ones often try to avoid large roads,
> highway=track is often avoided (though maybe it would not be described 
> as a road).

You're right, I overlooked bicycle routing profiles. However, if I'm not 
mistaken, these heuristics only use the highway=* value as a fallback 
for when keys like lanes=*, maxspeed=*, and smoothness=* are missing.

>         Functional classification isn't going for looks, though, it's
>         going for function. The states have spent a lot of time and
>         effort since FC was first introduced about a decade ago.
> 
> 
>     OK, but is it a good fit? The highway=* key (other than
>     highway=motorway) is defined as indicating the road's importance in
>     the road network. [1] That sounds vaguely functional. But the
>     ultimate goal of this key is indeed "going for looks", and optimal
>     routing behavior, because OSM data is primarily used by renderers
>     and routers.
> 
> Though functional classified roads (not by number of lanes of something) 
> are very useful.
> 
> When I was designing new road style for OSM Carto it was quite 
> irritating that in many regions
> people used highway=trunk for "double carriageway road" or "designated 
> as expressway".
> 
> It made basically impossible to have decent rendering on lower zoom 
> levels that would show
> basic structure of a road network.

Like many of the new state-level classification proposals, Kevin's 
proposal for New York would use expressway=yes rather than overloading 
highway=trunk. I think the debate here is about what to fill the 
highway=trunk slot with if we clear it of that historical anomaly.

-- 
minh at nguyen.cincinnati.oh.us