i'm deliberately not quoting or responding here in order to break out of the current, somewhat circular discussion.
the trunk classification does two things: 1) it influences rendering engines 2) it influences routing we all are familiar with what impact 1 has, but i think a lot of folks are throwing 2 about without having actually considered much about how the routing engines work. i'm not expert, but some of what i'm about to point out is pretty obvious if you have more than casual knowledge. routing engines usually have 2 alternative target routes, selectable by the user: a) shortest route b) fastest route for a, the distinction between trunk, primary, secondary, etc is pretty irrelevant. for b, it's ultimately looking for a driving time estimate. the US map is very short on maxspeed values right now. because of this, some if not all of the routers make maxspeed guesses based on highway classifications (i know MapQuest's router does, based on comments made at SOTM-US last year.) in short: a routing engine will probably use classifications where maxspeed data is missing, but probably only to derive guesstimates of maxspeed values. folks may want to factor this into their thinking on this topic. richard _______________________________________________ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
