[Talk-us] "System Continuity" in the Functional Classification network

[Max Erickson]

Broadly speaking, yes, such continuity should apply. Maybe not using
exactly the same rule as the US DOT.

In practice there is an overfocus on observing how a given stretch of
road is built and an underfocus on the role it plays in the network.
My pet example is this stretch of US 2 & 41:
http://www.openstreetmap.org/#map=16/45.9090/-86.9901

Several times it has been upgraded to trunk, to reflect that it is
dual carriageway. But it doesn't make any sense for a trunk road to
run the short distance between a tiny village and a small town. Lately
I've been leaning towards classifying most of US 2 as trunk, as it is
the major east-west corridor in the region. But the difference between
primary and trunk should be for the longer stretch of road, not just
to distinguish that one stretch is overbuilt.

Another example I see in the data is short cul-de-sacs tagged as
tertiary, sometimes alone and sometimes as the continuation across an
intersection of a longer road. The sensible classification for these
is frequently unclassified, because they serve as the public access
road for a small commercial or industrial area.


Max