I am fairly new to OSM, but have already completed a few edits. So, I think, I have a good basic understanding about the possibilities.
Recently, however, I was using my bike in Vienna and had my eTrex 30x calculate a route based on an OSM map. And I noticed that the device suggested a route that no cyclist in his right mind would ever choose, because it used a “highway” that is considered extremely dangerous for cyclists (two to four lanes, high speed, underpasses etc.). But I found no way to make the device avoid that highway.
So, I thought, I’d add that information directly to the map data. But how to do that? The thing is: It’s not exactly forbidden for cyclists to use that street, so it wouldn’t be correct to use the key “bicycle: no”. In some parts it would theoretically be possible to use “bicycle: use_sidepath”, but unfortunately not in all. (Please check, e.g., https://www.openstreetmap.org/#map=17/48.18086/16.35954: There’s absolutely no way a cyclists could/should use that big orange highway, but there also are no “side paths”). And it’s not exactly a motorway, so I can’t tell the eTrex to automatically avoid it.
So, is there a way to edit the map data, so that my eTrex will avoid that highway?
You probably should be using a Garmin file configured for bike routing. Generic files are trying to handle routing in multiple modes (I route for car, bike & foot on same file). In the past there have been a variety of specialised IMG files configured specifically for cycling. I’m only aware of 1: OpenMTBMap which is really aimed at off-road cycling.
In other words there is probably plenty of information already available in OSM to create routing rules which will not favour main roads for cycling. Also remember there may be very confident cyclists, such as professional couriers who want to take the most direct route.
Actually, I was using a Garmin file specifically for bike use, which is what caused my confusion. I do realize that the file contains good bicycle data so that whenever possible I am re-routed via dedicated bike lanes. In this case, however, there’s really no good way around that highway without making at least a slight detour, which seems to cause the router to use that street nonetheless. (Personally, I’d definitely consider this highway to be not suitable for cyclists, not even professional ones. But you might be right that there might be crazy ones. :))
But then again, Google Maps did not suggest that highway and suggested the correct detour (I used it for comparison). So, is there really no way to get (roughly) the same result with OSM data?
Unless there are official signs saying unsuitable for cyclists, this has to be addressed in the either the routing software or the preprocessor that prepares its working map. The only thing you can do on the OSM map itself is to make sure that things like the number of lanes and speed limits are correctly described.
OSM is not the place to put subjective information about suitability.
Yes, that’s what I thought, which is why I asked for help here. I just thought there might be some suggested tag to describe a kind of “suitability level” (e.g. only for professional cyclists, not for families) or a tag that says something like “discouraged, use only if nothing else is available”.
What was the actual route? Maybe you could post the URL for it using OSM’s online routing to see if it varies from what your Garmin suggests. Just ask OSM for the route and copy and paste the URL - something like this:
One cycle-friendly router to consider is cycle.travel’s (e.g. http://cycle.travel/map?lat=48.1807&lon=16.3614&zoom=16 ) - you could try the same thing there and see if that uses a “big road” when it shouldn’t, and when we know the route maybe we can suggest alternative tagging (if appropriate).
Which Garmin download were you using (or did you create the map yourself using mkgmap)? For my own use I create slightly customised Garmin maps for foot and car use - the “car” one excludes all non-car roads, and the foot one doesn’t (but does exclude any private paths and tracks). If it’s nearer, my Garmin handheld will tend to suggest that I walk on major roads (which like you cycling on them them, I don’t want to do). There was a bit of discussion (probably on the mkgmap mailing list) earlier this year abot “suggesting not to use a certain sort of road”. Maybe have a look through the archives there? They’re at http://www.mkgmap.org.uk/pipermail/mkgmap-dev/ and should be searchable.
I think this would be helpful as well but I realize that subjectivity isn’t ideal. There are a few roads here where people consistently drive over the speed limit, the lanes are narrow and feed into a faster highway and there is a high incidence of pedestrian/cyclist injuries. These are all not a subjective opinion. Is there a way to tag that?
Consistently over the speed limit would rule out every road that isn’t totally congested or in the immediate vicinity of a speed camera. For example, http://www.openstreetmap.org/way/23972515#map=16/51.5736/-0.3023 is on a designated cycle route and has a 20mph speed limit, but I’d estimate speeds of 40 mph are common, in the evening.
If you wanted to include actual speeds, you would need to find a usable source of measured speed distributions.
Again, for accident rates, you would want to include official, and with appropriate copyright releases, accident rates.
Otherwise, subjective judgements should be left to those making derived products, although there is the problem of identifying way splits, and associating the new ways with the original one.
One other thought. A lot of motorists may not like being stuck behind cyclists on narrow, quiet, roads, so they may mark those roads as unsuitable for cyclists.