<div dir="ltr"><div dir="ltr"><br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
The key issue with that approach: how does a mapper who isn't expert<br>
enough to grade accurately the difficulty of a MTB trail, but can<br>
clearly see, 'a road bike wouldn't work here', tag the thing<br>
appropriately? Simple 'highway=path foot=yes bicycle=yes' invites<br>
routing disasters. I can, and do, add 'surface=ground<br>
smoothness=horrible', but is that enough? How many tags must a router<br>
take into consideration before deciding that a cycleway is actually<br>
usable?<br></blockquote><div><br></div><div>This is not the correct tagging anyway for a (countryside or mountain) path, at least for those countries where the default access for highway=path implies bicycle=yes and horse=yes (legal access!).</div><div>And: the router should ignore the bicycle=yes tag on a highway=path.<br></div><div>highway=path on its own does not imply any indication about the suitability for using it on foot, on bicycle, or on horse.</div><div>The suitability can be indicated by a variety of tags:</div><div style="margin-left:40px">surface; smoothness; sac:scale; mtb:scale; incline; width; trail_visibility<br></div><div style="margin-left:40px">(leaving aside the special cases of bicycle|foot=designated|official which are, unfortunately, an established way of tagging mixed foot-cycle paths in general)<br></div><div>The mapper should insert those tags that she can assess on the ground or from other available sources. <br></div><div>It is these tags that a trekking bicycle router should assess: <br><div style="margin-left:40px">it should put a severe penalty on highpath=path without any additional tagging, or with bad surface, or with steep incline, or with mtb:scale>0, or with poor trail_visibility.</div></div><div style="margin-left:40px">it should assign a very low penalty to a highway=path with bicycle=designated, or to highway=cycleway <br></div>(most likely my tag examples are not complete, but this illustrates the concept)<br></div><div class="gmail_quote"><div><br></div></div></div>