[Tagging] traffic_signals:direction=* vs. direction=*

[Jean-Marc Liotier]

On Thu, 23 Mar 2017 00:57:44 +0100
Martin Koppenhoefer <dieterdreist at gmail.com> wrote:
>
> generally it is unsafe to rely on a "direction" like forward or
> backward as tag on a node. Nodes do not have directions, and there is
> no relation from a node to a single way, the relation is from a way
> to a node and many ways can reference the same node, that's not an
> error. Will it become forbidden to split ways on nodes with stop sign
> or traffic signal tags, because it breaks the information tagged on
> those nodes?

As the "complex intersections" section of the highway=traffic_signals
page describes a gradation of model complexity
(https://wiki.openstreetmap.org/wiki/Tag:highway%3Dtraffic_signals#Complex_intersections),
maybe coexistence is also possible between simple tagging of a
highway=stop+direction=forward node on the way to an intersection and a
complex relation-based model for more complex cases: having a simple
model that covers most cases has such significant benefit that I would
say it more than offsets the cost of having more than one way to do it.