[OSM-newbies] Highway Types and Speed Limits

[Mike Harris]

How does that work - I have numerous very local examples of highway=tertiary
(for example) where the speed limit changes between three values (30, 40, 60
mph) within quite short distances.

And after spending a summer driving in Finland I decided that there is a
Finnish law that says that the speed limit on any given road must change
(usually in increments of 20 kph - but sometimes 10 kph) at least once every
500 metres - with the speed cameras usually strategically placed to make
sure that you need to care about this! (No - I'm not complaining - I didn't
get caught - yet!).

Mike Harris
 

> -----Original Message-----
> From: Morten Kjeldgaard [mailto:mok at bioxray.au.dk] 
> Sent: 14 October 2009 20:31
> To: newbies at openstreetmap.org
> Subject: Re: [OSM-newbies] Highway Types and Speed Limits
> 
> 
> On 14/10/2009, at 10.06, Trevor Hook wrote:
> 
> > When I'm tagging say, a residential street, should I also 
> be tagging 
> > the 30mph speed limit that the residential street implies 
> (at least in 
> > the UK) or should I only tag if the street has a non-standard speed 
> > limit such as 20 or 40mph?
> 
> Is it really a good idea to tag the speed limit with a value? 
> Say the government decides to decrease the speed limits of 
> all rural roads with 5mph (e.g. to reduce CO2 emission), then 
> you have to correct the tagging on all roads. And it can't be 
> done using a script, since some roads with the same speed 
> limit value maybe shouldn't be changed.
> 
> I think it would be better to use a road classification 
> scheme for speed limits; then the mph value only needs to be 
> changed one place, namely the database entry that ties a 
> certain classification to a speed limit.
> 
> Cheers,
> Morten
> 
> 
> 
>