[Tagging] Basic question about functional classification of highways

SomeoneElse lists at mail.atownsend.org.uk
Tue Jun 17 12:24:14 UTC 2014


Andrew Shadura wrote:
>
> Both "maxspeed=<countrycode>:<zone type>" and "maxspeed=<zone type>" 
> are evil, as we need to have a separate DB for those zonal limits. 
> Please, just use maxspeed=<number>.
>

Any router that deals with more than one type of traffic will need to do 
that anyway, as many places have different limits that apply to cars, 
lorries, buses, things towing other things, etc.  The calculation is 
then something like "The speed limit for cars here is X.  For me that 
therefore means that the road type is Y and the speed limit for me is Z".

I've argued in the past for recording the fact that something isn't a 
numeric speed limit, but along with other people in the UK have adapted 
to the requirements of people writing car routers (which presumably 
support no other form of traffic*) by using "maxspeed:type=whatever" 
where it's a non-numeric maxspeed (leaving source:maxspeed for "sign" 
etc.), as that's often still needed too.

Cheers,

Andy

* I've yet to see a bicycle router enforce the "(pedalling) furiously" 
implications of 
http://www.legislation.gov.uk/ukpga/Vict/10-11/89#pb3-l1g18  , for example!



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