[OSM-talk] definition of the main highway-tag

[Greg Troxel]

Martin Koppenhoefer <dieterdreist at gmail.com> writes:

>>     secondary is typically used for travel at least 25km (between
>>     multiple towns)
>>     tertiary is used to get to secondary roads (to get to the 'real
>>     road' in the next town)
>
> this is working well for out-of-town situations. Inside urban

good point; that's what I am used to thinking about.

> agglomerations there should be different criteria though (and not
> necessarily they are physical, what is my point: let's put the
> definition according to everyday best-practise tagging).

I think these notions still work in cities, but less clearly.  primary
roads are those you'd get on to drive to the next big city.  Secondary
to get to outlying towns.  And tertiary to go all the way across the city.

The problem is that there is a continuous hierarchy of roads in terms of
importance, and when you get huge numbers of roads in the city the jump
From tertiary to residential/unclassified is too big and people tag
roads that aren't really tertiary as tertiary.  I'm seeing a bit of that
in Belmont (near Camridge, MA).

Maybe it's ok to have a lot of tertiary, to show the more important
local roads in cities.
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