Part of the issue here is how some countries in Europe sign speed limits. For example when you cross the border into Austria, there is a huge sign that lists what all the default speed limits are for various types of roads. They expect you to remember this. Local speed limit signs are only posted when the speed limit on a section of road diverges from the national default.
So for example, at the edge of a town where the speed limit goes from 80 to 100 km/h, the sign is actually an 80 with a slash through it indicating that the 80 zone is over and you may resume the default of 100 km/h which you remembered from the sign at the border. I believe this is the implicit vs explicit speed as Martin referred to it. In Europe they have used the source:maxspeed to indicate if the "source" of the maxspeed that applies to a given stretch of road is from an explicit sign or the implicit national default. Here in the U.S. such implicit speed limits are fairly rare except within cities where most residential roads are assumed to be 30 mph. All highways here are explicitly signed with the applicable speed limit so the established use of the source:maxspeed tag doesn't really make sense to most Americans. Toby On Thu, Mar 21, 2013 at 11:44 AM, Ian Dees <ian.d...@gmail.com> wrote: > On Thu, Mar 21, 2013 at 11:28 AM, Martin Koppenhoefer > <dieterdre...@gmail.com> wrote: >> >> The general usage is according to the wiki: >> distinguish between implicit and explicit speed limits (i.e. the >> default maxspeed in the context (urban, rural, motorway) and sign >> posted limits). The idea is to always add maxspeed=number(unit like >> mph or kmh) to highways and to distinguish where the limit comes from >> with the additional key source:maxspeed. > > > Since you didn't give specific examples I can't speak in specifics, but it > sounds like the mapper adding that value for the `source:maxspeed` tag is > using the tag correctly. They are specifying the source for the speedlimit > tag. They found the maxspeed value in a PDF somewhere. > > _______________________________________________ > Talk-us mailing list > Talk-us@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk-us > _______________________________________________ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
