[OSM-talk] Next: Relation name (WAS: Removing redundant routing instructions)

Colin Smale colin.smale at xs4all.nl
Tue Apr 28 18:09:09 UTC 2015


Look at either of the examples in the through_route proposal page. If
you are driving from bottom to top, you approach a Y-junction where two
roads diverge. Whether there is a give-way sign coming in the opposite
direction is not sufficient to understand which branch of the Y is the
"through route" as seen "from below" as it were - the "through route"
may not be symmetrical. I don't have an example of this to hand, but it
wouldn't be right to exclude this possibility. 

And yes, there are junctions without a through route. In the USA you
have four-way-stops whereby all roads see a stop sign. Sequencing is a
bit informal - first-come-first-served in theory I believe, but that
doesn't always work of course. Closer to home in continental Europe
there are many junctions (away from main roads) which use "priority from
the right" - i.e. all roads are deemed equal and no one road/route has
priority over the others. These junctions are usually unmarked (i.e. no
white lines and no signs) because they are deemed to be "default" in the
absence of "priority road" signs (yellow diamonds). 


On 2015-04-28 18:25, pmailkeey . wrote: 

> On 28 April 2015 at 16:25, Colin Smale <colin.smale at xs4all.nl> wrote:
>> The "give way" sign won't help to distinguish between the arms where two roads diverge...
> You mean neither has give way markings ? Can you provide an example ? It's sounding a bit like Russia ! 
>> By the way, the sign is often a STOP sign, so the logic will have to check for both.
> Whether 'often' or not, that's true. That made me think of another peculiarity - but it's not a stop, just a give way on the through route. So yes, I've found a give way on the through route ! I guess this is a bit like the mini roundabout scenario. Can we accept the concept of not having a through route at a junction ? In the case I've found, there's no continuity - different number,different name, give way but is a continuation of the main route! 
> -- 
> Mike. 
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