[mkgmap-dev] STOP signs and routing

Mon Sep 20 12:22:58 BST 2010

On 09/20/2010 01:43 PM, maning sambale wrote:
> A thread for improving routing gave this suggestion in the points style.
>
> highway=traffic_signals { add mkgmap:road-speed = '-2'; add
> mkgmap:road-speed-min = '1' }
> highway=crossing { add mkgmap:road-speed = '-1'; add
> mkgmap:road-speed-min = '1' }
> highway=stop { add mkgmap:road-speed = '-2'; add mkgmap:road-speed-min = '1' }
> traffic_calming=* { add mkgmap:road-speed = '-2'; add
> mkgmap:road-speed-min = '1' }
> barrier=toll_booth { add mkgmap:road-speed = '-2'; add
> mkgmap:road-speed-min = '1' }
>
> The reduces the road speed of the way with the traffic_signal node.
> I haven't tested fully but it seems to improve time calculation.

I have tested it. There seems to be two major problems with that. First 
of all, it lowers the speed of the segment that has the poi. Lenght of 
that segment is sometimes just a few meters, sometimes a long road.

So, it is more or less based on luck, whether the calculation of time is 
better or not. In any case, the time calculated should be longer. 
Matters could be improved by for example making an automatic split for a 
road if the segment containing speed-lowering poi gets too long.

Another problem is with Garmin routing. I'd be more interested in 
avoiding the low-speed points. However, Garmin does not use road speed 
too intelligently. Instead it seems to calculate the route based on 
road_class mostly.
--
Harri