[OSM-talk] Tagging for street danger levels

[Toby Murray]

Someone in my area is starting up a new website that is focused on
cycling in the city. They have decided to use OSM as their map which
is awesome. The question is: are there any tagging conventions to
indicate how dangerous a particular stretch of road is to cyclists?
They want to produce a map of the city that highlights the dangerous
roads to avoid in order to show how they act as barriers and make it
very difficult to move around town on a bicycle. I could also see a
different map that highlights the safest roads and paths. It seems
like this information would also be useful to routing services to be
able to come up with bicycle specific routes that avoid the "certain
death" roads.

I see a "hazard=" tag but it doesn't seem to be used very much and is
a little too general for what I had in mind. Perhaps hazard:cycle=
with some kind of hazard level indication would work. I could see
using numbers (0=safe path or bike lane, 1=residential/low traffic
road, 2=bigger roads with higher speed traffic, 3=avoid at all costs)
or some other string based identifier if that is deemed easier to
understand. Some of this information could probably be implied by the
highway= tag but that is a pretty incomplete picture. There are parts
of the same road here in town that vary between different levels,
usually getting far more dangerous when they hit a hill and start
curving around. Also, there are several highways leading out of town
that are similar to each other except for traffic flow which makes
some of them absolutely wonderful to ride on while others are a death
trap. I realize this can be somewhat subjective but I think there
could be pretty good consensus among cyclists in a given area.

Since I haven't found any tags on the subject I'm assuming there is no
renderer support for such a concept either so I may end up trying to
do some custom rendering which is another topic entirely... But I'm
thinking if there is a consensus on this then support for it could be
added to opencyclemap, hikebikemap, etc.

Thoughts?

Toby