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IMHO, the appropriate use of maxspeed is already well defined in the wiki: <A HREF="http://wiki.openstreetmap.org/wiki/Key:maxspeed">http://wiki.openstreetmap.org/wiki/Key:maxspeed</A><BR>
<BR>
Currently, the wiki states:<BR>
What to do if the real possible speed is below the allowed speed?
<DL>
<DL>
<UL>
<LI>Always tag the allowed speed (as <B><TT>maxspeed</TT></B><TT>=*</TT>)!
<LI>Add <TT><A HREF="http://wiki.openstreetmap.org/index.php?title=Key:maxspeed:practical&action=edit&redlink=1">maxspeed:practical</A>=*</TT> for the real maxspeed.
</UL>
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</DL>
<BR>
The defaults for maxspeed are given here: <A HREF="http://wiki.openstreetmap.org/wiki/OSM_tags_for_routing/Maxspeed">http://wiki.openstreetmap.org/wiki/OSM_tags_for_routing/Maxspeed</A><BR>
<BR>
In the US, speed limits apply equally to bicycle, motorcycle and automobiles.<BR>
I have yet to meet a pedestrian who would exceed a 5mph speed limit, and I can't remember seeing a speed limit sign with a lower value.<BR>
<BR>
At some point, logic needs to kick in. The driver of a top-heavy, overloaded vehicle, of a sort that he has never driven before, driving through rush-hour traffic, in the rain, on a one-lane two-way unpaved windy road, through the mountains, without guard-rails, should not reasonably expect *any* indication from a GPS as to realistic travel times. One expecting such should have their driver's license revoked, and be confined with medical staff nearby at all times.<BR>
<BR>
In the US, maximum "legal speed limits" are frequently indicated with signs, and sharp curves are usually denoted with "caution" signs, indicating a maximum "safe" speed. Being that these are preset, they would not need to be calculated, but should rather be tagged as-is.<BR>
<BR>
I should think that a GPS unit would have high value when driving in an unfamiliar area. In my local area, you might see one speed limit sign on the entire length of a main road, at the beginning of the road. Traffic entering the road at an intersection somewhere along the route would not see a speed limit sign on the route at all, even after traveling 60 or more miles.<BR>
<BR>
On Mon, 2008-12-08 at 15:04 +0100, Thomas Meller wrote:
<BLOCKQUOTE TYPE=CITE>
<PRE>
IMHO setting a speedlimit does not do a good job for every case.
Does it count for bicycle riders?
Does it count for motorbike riders?
Does it count for pedestrians?
OSM, as I understood, aims at being a universally usable source for orientation and routing
for every type of traffic.
Reasonable speedlimits are very individual. They depend on the driver's/rider's skills, the vehicle used, the way's inclination, load, daily mood and goal aimed at.
Think of a lorry, filled with the driver's furniture, crossing a mountain pass.
Compare it with a motorbike, rider and sozius, packed with tent and air mattresses, on a holiday trip through the Schwarzwald.
Or have a look at a couple on a tandem bike, crossing the Swiss Alps in their holidays - or the Netherlands.
As a hint for speed, the vehicle type, the street's width, the count and shape of curves and the current traffic situation are much more reasonable.
I have some ideas for judging the shape of a curve, but am not capable to make a code example.
Maybe someone already has some programming experience and likes a trial? The task is not really profane and depends highly on the quality of the OSM-data, but I think it should be possible to write an interface for judging a way's shape independent of the vehicle type.
-------- Original-Nachricht --------
> Datum: Sun, 7 Dec 2008 12:50:34 +0100
> Von: "Fabrizio Carrai" <<A HREF="mailto:fabrizio.carrai@gmail.com">fabrizio.carrai@gmail.com</A>>
> An: <A HREF="mailto:newbies@openstreetmap.org">newbies@openstreetmap.org</A>
> Betreff: [OSM-newbies] R: Speed Limits
> What Rally is saying is more than correct for the current level of
> navigators. But thinking to an innovative navigator, the John's
> information
> looks very interesting.
> Exact time travel could be estimated using the correct speed limit
> available
> at the road's usage time. But we could also think to something for
> evoluted:
> the variation of the speed could be not only function of the time, but
> also
> of the assesed traffic ondition (statistically or real time assessed).
>
> I think that having tags supporting the John's data, could add an
> interesting support to very advanced applications.
>
> I'm a recent contibutor to the OSM project, and I would like to use this
> thread to learn a bit more on the common idea to be used to add tags (and
> to
> propose new ones..) to the ways.
> >From other threads I understood (please, correct me), that we do not map
> for
> the application and its capabilities (render, navigator, etc..) but more
> for
> the completeness of the informations that, indeed, coudl drive any kind of
> application.
> Looking from a more high point of view is a kind of life-loop: data exists
> because there are applications that use them, and applications could
> exploit
> new features only if the map data are adequately detailed.
>
> Fabrizio
> -----Messaggio originale-----
> Da: <A HREF="mailto:newbies-bounces@openstreetmap.org">newbies-bounces@openstreetmap.org</A>
> [<A HREF="mailto:newbies-bounces@openstreetmap.org">mailto:newbies-bounces@openstreetmap.org</A>]Per conto di Rally de Leon
> Inviato: venerdì 5 dicembre 2008 20.10
> A: <A HREF="mailto:john@swajime.com">john@swajime.com</A>; <A HREF="mailto:newbies@openstreetmap.org">newbies@openstreetmap.org</A>
> Oggetto: Re: [OSM-newbies] Speed Limits
>
>
> The most practical use of maxspeed on maps is to estimate the "travel
> time" of a particular route in a gps map of a navigational device, rather
> than just warn you if you are above the speed limit.
>
> It's always better to use the conservative value (lower speed limit) to
> estimate your travel time (so that the gps device can calculate and show
> you
> that fastest route without breaking the max speed)
>
>
> On Fri, Dec 5, 2008 at 10:09 PM, John Wesley Simpson <<A HREF="mailto:john@swajime.com">john@swajime.com</A>>
> wrote:
>
> Howdy,
>
> I'm trying to use maxspeed to put in speed limits for roads in my
> local
> area.
>
> One of the roads has a speed limit of 55mph if you are northbound, but
> 50mph if you are southbound.
>
> Another road has a speed limit of 70mph in the daytime, but 65mph at
> nighttime.
>
> How should these be entered?
>
> Is there a web-page that specifically explains how to enter these
> situations into the editor?
>
> --
> John Wesley Simpson <<A HREF="mailto:john@swajime.com">john@swajime.com</A>>
> SwaJime's Cove
>
>
>
> _______________________________________________
> newbies mailing list
> <A HREF="mailto:newbies@openstreetmap.org">newbies@openstreetmap.org</A>
> <A HREF="http://lists.openstreetmap.org/listinfo/newbies">http://lists.openstreetmap.org/listinfo/newbies</A>
>
>
</PRE>
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