> On May 6, 2017, at 1:11 AM, Paul Johnson <[email protected]> wrote: > > > > On Sat, May 6, 2017 at 3:07 AM, Paul Johnson <[email protected] > <mailto:[email protected]>> wrote: > > > On Fri, May 5, 2017 at 7:55 AM, Horea Meleg <[email protected] > <mailto:[email protected]>> wrote: > > A lot of motorway_links don’t have a speed limit sign. Do you have any idea > where could we get the speed limit values from? > In North America, ramps with speed limits are relatively rare, but following > the usual rule that the previous speed limit applies, the speed limit of the > off-ramp would be the same as the freeway itself unless otherwise posted, and > if the same ramp returns to the freeway contiguously, that speed limit would > continue to carry over to the on-ramp. It's not very much more complicated > than that, but in practice, just leave off maxspeed on the ramps entirely > unless it's actually posted with a regulatory (white sign) speed limit or a > general speed limit is known (both relatively uncommon). maxspeed:advisory > would be far more common, as exit ramps are nearly universally posted with an > advised (yellow sign) speed. > > Adding to my own answer again, I should say rather than "in practice, just > leave off maxspeed" but rather, "in practice, it never comes up so people > rarely tag it." I don't mind adding these if folks consider that favorable > (I do see the value). >
From a end user of a routing app on my phone that uses OSM data, I’d rather have the maxspeed omitted from *_link ways if it is not signed. The reason is that there are some freeway/freeway ramp geometries where traveling by the ramp is slightly shorter than keeping on the freeway. I’ve seen cases where that caused the app I use to route me off the freeway and then immediately back on. If there is no maxspeed tag, I can set the default for the *_link such that I am not needlessly routed off and then back on a freeway. I guess that is “omitting tags for the data consumer”, but since we are discussion situations where there is no sign and, in general, we tag what we see I don’t see that as being too far from the normal tagging philosophy. Cheers, Tod
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