Am Thursday 21 May 2009 schrieb Lester Caine: > > right, all roads have a defined limit. > > the proposal is: > > if there is a sign for a speed limit: use maxspeed = ... > > if not: use zone:traffic = ... > > the maxspeed here can be derived from the zone tag. > > For routing purposes ... building the time for a route ... > If maxspeed is set - use maxspeed, otherwise use the default for the > highway= type for your country which would imply that zone:traffic= is > equivalent to highway=(residential/in_town) based on country again. > the zones don't have to be equivalent to the highway-types! maybe most time they are, but not everywhere; an example: I see it very often, that the place sign stand some hundred meters before the buildings begin. the residential highway would be where the buildings are, but the zone starts these som hundred meters earlier.
you will also have different highway-types like primary/secondary/residential/... inside the same zone:traffic. > All of that needs adding to > http://wiki.openstreetmap.org/wiki/Proposed_features/trafficzone > ( now that I've found it ... ) > but rule one is 'highway=' should exist for every road so if that > highway=motorway takes priority and should define any other motorway > conditions that apply, and maxspeed then adjusts the motorway limit if > required. right. the primary default is the zone. if a highway type implies some other attributes, those will be used. if there are signs tagged somehow, they will override evereything else. > Rendering and routing use the highway= tag to identify roads, and can > add speed limits based on the existing rules. > Additional traffic restrictions would be linked to > highway=DE:residential rather than creating yet another minefield? > right. > I've made a case in the past for replacing a lot of this with simple > numeric tags that display text using your local country code, but having > something like highway=residential pulling up the local set of default > rules - such as the above for DE located roads - looks a lot more > practical than adding yet another set of 'rules' that need tags adding? > I think, we will need new tags for all kinds of restrictions that may occur some day. > The motorway restrictions are FULLY variable, in that the traffic > management centre will apply them as need demands, and the hard shoulder > of motorways can be introduced as an extra lane in some areas to reduce > conjestion - at any time. the thing with the extra lane is also done in germany. but I wouldn't know how to tag this, because there's no certain time or other base when this is active. maybe as an extension of the lanes-key... > Now if we had a website that gives the current status of each of these > situations then things would be easier, but if you are not going to > reach an area for some time, then even that is not a lot of help :( > But these are basically variable rules applied to maxspeed= and > overiding the default normally applied. I think those dynamic maxspeeds based on the traffic can't be mapped in a useful way. a router would have to use TMC or other realtime sources to know the current state. what we could do as a hint for routers and drivers, is adding the information that the road is equipped with a traffic guidance system.
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