[OSRM-talk] Huge difference in needed time computation OSRM / Google Maps

[Emil Tin]

Interesting, but keep in mind that the speed specified in the profile is the starting point; signals and turns incur delays, which means the overall speed might be lower.

In Copenhagen we used Bluetooth/wifi antennas to measure speed of cars and bikes on a rather big street, and cars didn't move faster than bikes, in fact often slower. Bikes go at 20 km/h average when they're actually moving, whereas average with stops is more like 14-15 km/h.

Emil



-----Oprindelig meddelelse-----
Fra: Markus Semm [mailto:msemm at enaikoon.de] 
Sendt: 28. marts 2014 11:14
Til: OSRM-talk at openstreetmap.org
Emne: Re: [OSRM-talk] Huge difference in needed time computation OSRM / Google Maps

Hi,
I know from a Berlin based Taxi company that the average speed in Berlin is 22 km/h Markus

-----Ursprüngliche Nachricht-----
Von: Rudolf Mayer [mailto:rudolf.mayer at gmail.com]
Gesendet: Freitag, 28. März 2014 11:11
An: osrm-talk at openstreetmap.org
Betreff: Re: [OSRM-talk] Huge difference in needed time computation OSRM / Google Maps

Hi Emil!

Thanks for pointing this out!

Indeed the limit to 2/3 of the max speed seems a bit too conservative, that is, at least outside of cities; inside city limits you could argue that it is ok, at least as long as there is no turn penalties and traffic light penalties implemented; and you generally can always expect a bus or slow traffic.. :-)

I am still wondering whether also the number of lanes is considered in the example. I think that other routers consider this, and if a road has more than 1 lane per direction, the speed reduction is less severe, or at least that road is preferred over other roads that are single lanes per direction.

greetings
rudi

[Emil Tin], On 2014-03-28 09:33:
>
>
> Hi,
> The following issue might contribute to inflated travel time:
> https://github.com/DennisOSRM/Project-OSRM/pull/969
>
>
> Emil Tin
> City of Copenhagen
>
>
> -----Oprindelig meddelelse-----
> Fra: Rudolf Mayer [mailto:rudolf.mayer at gmail.com]
> Sendt: 24. marts 2014 13:30
> Til: OSRM-talk at openstreetmap.org
> Emne: [OSRM-talk] Huge difference in needed time computation OSRM / 
> Google Maps
>
> Hi everyone!
>
> I tried to compute the following route:
>
> http://osrm.at/?hl=en&loc=48.208845,16.372329&loc=48.276104,16.791565
>
> And get this as a proposed result:
>
> Route Description
> (B3 - L2)
> Distance:	44.4 km
> Duration:	1 h 15 min
>
>
> This seems very wrong, though, Google maps estimates
> (http://goo.gl/maps/EPt14)
>
> a.) a likely more optimal route, preferring bigger streets
>
> b.) estimates 45,1 km, 47 Minutes. Almsot 30 mins difference in a 47 minutes route seems way off...
>
>
> I am not sure what this is caused by, the map data seems ok for this route.
>
>
> Besides this huge time difference, one particullarily interesting 
> detail in the routing is at http://osrm.at/6PV, where OSRM prefers a 
> short cut through a much smaller street (tertiary vs primary) that has 
> much more crossings, and http://osrm.at/6PW would be the much preferred rout..
>
> Any ideas why this is happening?
>
> greetings
> rudi
>
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