[OSM-newbies] R: Speed Limits
John Wesley Simpson
john at swajime.com
Mon Dec 8 14:58:10 GMT 2008
IMHO, the appropriate use of maxspeed is already well defined in the
wiki: http://wiki.openstreetmap.org/wiki/Key:maxspeed
Currently, the wiki states:
What to do if the real possible speed is below the allowed speed?
* Always tag the allowed speed (as maxspeed=*)!
* Add maxspeed:practical=* for the real maxspeed.
The defaults for maxspeed are given here:
http://wiki.openstreetmap.org/wiki/OSM_tags_for_routing/Maxspeed
In the US, speed limits apply equally to bicycle, motorcycle and
automobiles.
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.
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.
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.
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.
On Mon, 2008-12-08 at 15:04 +0100, Thomas Meller wrote:
> 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" <fabrizio.carrai at gmail.com>
> > An: newbies at openstreetmap.org
> > 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: newbies-bounces at openstreetmap.org
> > [mailto:newbies-bounces at openstreetmap.org]Per conto di Rally de Leon
> > Inviato: venerdì 5 dicembre 2008 20.10
> > A: john at swajime.com; newbies at openstreetmap.org
> > 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 <john at swajime.com>
> > 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 <john at swajime.com>
> > SwaJime's Cove
> >
> >
> >
> > _______________________________________________
> > newbies mailing list
> > newbies at openstreetmap.org
> > http://lists.openstreetmap.org/listinfo/newbies
> >
> >
>
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