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<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-family:'NokiaPureTextLight';"> I would not consider a roundabout or a slip road to be any different to that signposted. </span></p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-family:'NokiaPureTextLight';">Whilst exceeding 60 on a roundabout is unlikely, I would consider the limit to be that of the road it is joining.</span></p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-family:'NokiaPureTextLight';">In the days before the chopsticks signs on motorways, and still in Scotland, the 70 sign was at the start of the sliproad.</span></p>
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; font-family:'NokiaPureTextLight';"><br></p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-family:'NokiaPureTextLight';">Phil</span></p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-family:'NokiaPureTextLight';">--</span></p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-family:'NokiaPureTextLight';"> </span></p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-family:'NokiaPureTextLight';">Sent from my Nokia N9</span></p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"><span style=" font-family:'NokiaPureTextLight';"> </span></p></div><br><div id="fenix-reply-header"><p>On 27/09/2012 10:10 Robert Whittaker (OSM) wrote:<br></p></div><div id="fenix-quoted-body"><div>
On 26 September 2012 18:55, Peter Miller <<a href="mailto:peter.miller@itoworld.com">peter.miller@itoworld.com</a>> wrote:<br>
> There does seem to be a a massive consensus around the world that maxspeed<br>
> should be used to hold a posted speed limit in km/h or mph as a numeric in<br>
> the local units.<br>
<br>
+1<br>
<br>
</div>
<div>
> There seems to be a mood to use maxspeed:type for the supporting<br>
> countrycode:zone data here, although more people are using source:maxspeed<br>
> for this globally. I have continued to use maxspeed:type in my cleanup pass<br>
> because in a number of cases the source:maxspeed already contained something<br>
> like 'survey', 'sign at S end' or similar.<br>
><br>
> I suggest that we raise a proposal at some point to migrate the zone<br>
> information to maxspeed:type, but lets not worry about that for now.<br>
<br>
</div>
<div>
I've always used source:maxspeed for this, as I was under the<br>
impression that that was the consensus. However, I've always felt it<br>
wasn't quite right, so I'd be more than happy to switch to using<br>
maxspeed:type instead, and don't object to anyone who wants to convert<br>
any of my previously added source:maxspeed=GB:* tags.<br>
<br>
</div>
<div>
> Based on the dilemma I have had numerous times in the past week to decide is<br>
> a slip-road or roundabout is technically a 60mph or 70mph I would suggest<br>
> that we produce some guidance on what value to use in various situations<br>
> (even though it is a bit irrelevant and nerdy for most situations we could<br>
> imagine). I tag slip roads at the dual carriageway speed if at least one end<br>
> is on a dual-carriageway. I tag roundabouts as 70mph if there are at least<br>
> two dual-carriageways attached to them. I use 60 mph in other situations.<br>
<br>
</div>
<div>
My understanding (which may be wrong) is that the Dual Carriageway<br>
speed limit applies only on roads where there are two separated<br>
carriageways, and not just a one-way bit of road. Since roundabouts<br>
arguably are a one-way loop, rather than having two separated<br>
carriageways, I'd say they have a national speed limit of 60 rather<br>
than 70. I think I'd also claim that slip-roads with at least one end<br>
on a non-dual carriageway would be 60 too, ie the 70 doesn't start<br>
until you're actually on the dual carriageway proper. Slip roads which<br>
result from one dual carriageway merging into another would be more of<br>
a grey area...<br>
<br>
</div>
<div>
Presumably this is something that we could check with an appropriate<br>
government agency, though, and then we'd be able to tag things<br>
correctly.<br>
<br>
</div>
<div>
> Given that it is not always 100% clear if a road is 'dual' or 'single', I<br>
> suggest that we simply use use a value 'UK:national' in maxspeed:type (or in<br>
> source:maxspeed). This would be in place of uk:motorway, uk:nsl_single and<br>
> uk:nsl_dual. To be clear, the tag should be uk:national not just national<br>
> given the strong guidance on the wiki and through usage that it is<br>
> appropriate to include a country-code prefix.<br>
<br>
</div>
<div>
BTW: I believe that the country code for the UK is "GB" so all the<br>
tags should be GB:* rather than UK:*.<br>
<br>
</div>
<div>
Secondly, in terms of making the tagging useful, I think it's highly<br>
desirable to be able to distinguish between motorway, nsl_single and<br>
nsl_dual. This is because some classes of vehicle will have different<br>
speed limits on different classes of road (so it would be good to<br>
allow routing tools access to the information), and also because the<br>
speed limits for one of more of the classes might change at some point<br>
in the future. (Ok, I think you could probably deduce the road class<br>
from the values of highway maxspeed tags, but I still think it would<br>
be better to have the information there explicitly to make it easier<br>
for data users and consistency checking.)<br>
<br>
</div>
<div>
Robert.<br>
<br>
-- <br>
</div>
<div>
Robert Whittaker<br>
<br>
_______________________________________________<br>
</div>
<div>
Talk-GB mailing list<br>
</div>
<div>
<a href="mailto:peter.miller@itoworld.com">peter.miller@itoworld.com</a><br>
<a href="http://lists.openstreetmap.org/listinfo/talk-gb">http://lists.openstreetmap.org/listinfo/talk-gb</a><br>
<br>
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