[Tagging] Tagging average speed [Was: Re: Residential roads]

[Peter Wendorff]

  On 03.10.2010 17:16, Ralf Kleineisel wrote:
> On 10/03/2010 05:04 PM, Anthony wrote:
>
>> Maybe it's just because of where I live, but I don't see how it would be.
> Well, where I live (Germany) we have a legal limit of 100 kph on roads
> outside of cities, motorways excluded. This legally applies even to
> small roads if there is no sign indicating a lower limit. On many roads
> you can achieve this speed, too. But on the other hand we have lots of
> narrow, twisty country roads where a normal driver does not go faster
> than 60 kph. In the Alps it is even more drastic. For estimating the
> time someone will probably need to drive along a road this information
> would be very helpful.
Sophisticated routing systems include the shape of roads (curves, width, 
surface quality) and their importance for routing networks, but I don't 
think, that should be added as mostly static attributes to the osm database.

This would be a real huge effort, and I fear, it wouldn't really help.
To achieve a hopefully useful system, we would have to model:
- speed between monday and friday
- speed at weekends (in Germany different additional due to heavy goods 
being forbidden to drive at weekends partly),
- speed at different daytimes,
- speed in different seasons (here where I live, there often is 
agricultural traffic with really slow speed you have to wait behind; at 
least in fall)
- speed at different weather conditions (rain, icy road, leaves at autumn)
- speed at holiday times

To be useful, this has to be
- nearly complete
- up to date with changes at road network around
- measured in a slightly comparable, and objective fashion.

I think, that's neither possible nor useful inside the osm database.

regards
Peter