[mkgmap-dev] Road speed through urban areas

Thu Jul 16 09:35:35 BST 2020

That approach based on POIs does not work too well. You have no idea if 
you lower the speed for a short segment or a long one, it just depends 
on eg. if there are traffic lights on long or short segment. Same 
problem with other poi types like crossings.

BTW, For another message suggesting lower road classes. I'd not lower 
road classes too much. According to my tests garmin seems to ignore 
lower road classes on long trips (except near ends) and if there are 
huge number of equal road classes, route calculation time can get really 
large.

I tried a few years back lifting cycleways to category similar to 
motorways (to get better cycling routing). That resulted in route 
calculation times like 10 or 15 minutes for a 10km trip in the city. (At 
least on my older Oregon).

On 7/16/20 11:14 AM, Joris Bo wrote:
> Hi,
> 
> In urban areas the 'practical maxspeed' is often lower then the 'official' maxspeed because of existence of traffic lights and traffic calmers.
> I would rely on the intended routing basics of road_class and corresponding maxspeeds and the common usage of highway types and tagging in osm.
> 
> Maybe it helps to make these roads less attractive for the routing engines to check for traffic lights.
> Because these are node-tags and not line-tags I don't know the exact impact.
> 
> highway = residential & highway=crossing & crossing=traffic_signals {set mkgmap:road-speed=-2}
> highway = residential & traffic_calming=table	{ set mkgmap:road-speed=-1}
> highway = residential & access = destination { set mkgmap:road-speed=-2}
> 
> Joris