On Saturday, October 10, 2020 at 7:33:29 PM UTC+2 Greg Troxel wrote:
> > Paul van der Hulst <[email protected]> writes: > > > Hi, > > It seems there is some consensus about the 130 limit on the > > on-ramp: https://forum.openstreetmap.org/viewtopic.php?id=70677 (in > dutch > > unfortunately) so apparently this should be solved in the routing > algorithm. > > can you translate? DO you mean "the legal speed is 130 km/h"? Do you > then also mean "it is normal and reasonable to drive at that speed"? > and "people typically do drive at that speed"? > > Openstreetmap does not store data about what is normal or reasonable, that would be pointless. On the linked openstreetmap forum page there is consensus that the way it is currently stored in openstreetmap is ok, given the maximum speed laws. The reason is that on the on-ramp, typically only a highway sign is given, which implies 130km/h. When you have entered the main road there will be a sign that during daytime there is a 100km/h limit. The daytime restriction is missing on the on-ramp, therefore the openstreetmap data is considered correct. > I can see at least two ways to tackle this. > > 1 - I don't know how normal crossings are modeled, but I assume some > > assumption is made that you (sometimes?) have to slow down when you > cross > > other roads. > > A fair point. > > > In the Netherlands, these highways should never join with roads of lower > > order. If a highway link does, that counts as a normal crossing where > you > > would have to assume some delay due to crossing traffic. > > > 2 - It is quite irresponsible to assume you can race past a point on the > > map at 130km/h where the maximum speed of one of the connecting roads is > > only 80. The maximum speed at any point on the map should be no higher > than > > the lowest of the speed limits of the connecting roads. > > Do they have ramp junctions, or stop signs? > > Sounds like maxpseed:advisory is in order. > > Is it really the case that the signs say 130 and nothing else? How is a > driver to know that they should slow down? > See my remark above. About possible stop signs: on the off-ramp there will usually first be a sign that the highway is about to end in 300m (= at the crossing) and again one just before the crossing itself. On the crossing chances are high that you have to yield to traffic from left or right, or possibly make a full stop. When you continue straight ahead to return to the main highway (instead of turning left or right) you will meet a sign that you're back on the highway, without any speed restrictions on the sign, implying a 130km/h limit. The end-of-highway sign is typically only a few meters before the actual crossing, not enough to split the way into a separate section with a reduced speed limit. So the situation is actually as described in option 2: only on the crossing, the road has a 80km/h limit. You can therefore not cross it at 100 or even 130km/h. At the least, a routing algorithm should acknowledge the reduced speed limit and add reasonable delays for slowing down and accelerating. This includes *single points* with lower maxspeed. Best regards, Paul -- You received this message because you are subscribed to the Google Groups "OsmAnd" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/osmand/859740bb-c200-43cd-9e0e-b32fbcc2fddfn%40googlegroups.com.
