[Talk-us] Highway classification questions

stevea steveaOSM at softworkers.com
Wed Oct 16 18:40:18 UTC 2013

L. David Baron wrote:
>  > Should Central Expressway be marked as primary rather than trunk 
>at this point? The existence of a traffic signal indicates that it 
>does not always have right of way. Other sections of Central 
>Expressway are grade separated with limited access and highway=trunk 
>makes sense to me but not here.
>I'd note that the entire Santa Clara county expressway system all
>seems to be tagged as highway=trunk, and if memory serves, most of
>those roads (e.g., Foothill Expressway, Oregon Expressway, Lawrence
>Expressway) have significant numbers of intersecting traffic lights.
>I think that section of Central Expressway that's grade-separated
>(is it all but the northwestern end?) is actually unusual for the
>system.  But it looks like the entire system is tagged as
>Such a change would also disguise that there's a massive change in
>the character of the road (loss of divider, change in speed limit,
>and drastic change in lane widths) where it crosses San Antonio and
>turns into Alma Street.
>(If anything, the spot in the area where I'd question a
>highway=trunk tagging is Page Mill Road from El Camino to 280.)

Santa Clara County Expressways (SCCE) have a colorful history.  Their 
current incarnation is "Phase 2 of a three-phase plan to turn them 
into freeways" but voters have repeatedly voted down funding for the 
third phase.  So, they remain in an odd limbo for California.  I am 
of the opinion that for OSM tagging purposes, a systemwide (Santa 
Clara County wide) trunk designation is appropriate.

I used to drive Page Mill from 280 to El Camino every weekday (for a 
client).  While there are MANY traffic signals, I'd still call it a 
trunk:  it carries vast daily counts of traffic and critically links 
an interstate freeway and a state (non-freeway) highway.  There may 
be other places in the SCCE system which might warrant being changed 
from trunk to primary (PM from 280 to El Camino included, now that I 
think of it), but those would really need to be examined on a 
case-by-case basis.  Tagging "highway=trunk" SCCE systemwide is a 
good place to start.


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