Routing in USA with online GraphHopper when maxspeed tags are missing. How does it get this right?

Open Source Routing Engine
1

Hi all,

I have observed that for USA the online version of GraphHopper appears to be using speed data that is not available in the OpenStreetMaps database. Can anyone help me understand where this data is coming from?

Example:
The online GraphHopper calculates the following simple route along a single road as 51 mph (82 kph) using the distance/time from the raw response. I have verified that this is pretty accurate according to the road signs.
GraphHopper for East Wyatt Earp Boulevard
However the same road in OSM does not have any maxspeed tag provided.
OpenStreetMaps for East Wyatt Earp Boulevard
Therefore I assume the speeds are either coming from a different source or falling back on a default value. When I investigated the default speeds used by cars in the CarFlagEncoder in GraphHopper v2.1 I can see that default speed for this class of highway is 40 mph (65 kph). So, unless these values have been tuned much better for the US in newer versions of GraphHopper, I am mystified about how this can be accurate.

Can anyone enlighten me about how the online version of GraphHopper can be accurate in USA when the underlying data appears to be missing? Thanks in advance.

2

We just guess in those cases for our commercial setup, there is no additional speed data we use for OpenStreetMap at the moment.

We also plan and try to improve the open source ETAs so that at one day in the future they are identical to our commercial setup and together with the community we can easily improve it. See also https://discuss.graphhopper.com/t/difference-between-open-source-car-and-graphhopper-maps-car/3379/2

3

Hello, was the link that’s provided private? Following it returns the following message “Oops! That page doesn’t exist or is private.”

Is the guess based on similar logic to the default car encoder that guesses what maxspeed is appropriate based on the road class or other way attributes?

4

It seems the author deleted it - have resurrected it.

5

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