Estimated time inaccurate for "fastest available" routes

Discussion Routing
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#1

I think I have found an issue with the estimated travel time calculated by Kurviger.

I read this documentation, and couldn’t find anything regarding this issue, or travel time estimation in general.

This issue appears to be most prevalent when using the fastest available setting.

Route 1 below, when set to the fastest available option, provides a travel time estimate of ~6-6.5 hours in Kurviger when in reality, they are closer to 4.5 hours.
Route 2 estimates 2.5 and ~2 hours for Kurviger (fastest available) and GMaps respectively.
For the two examples provided below, the estimate provided by GMaps is accurate (or at least very close). The route I drove yesterday (similar to route 1) was generated with the extra curvy setting, which provides an estimate of ~10 hours. This estimate proved to be much more accurate, although with the stops I made along the way, it is a bit hard to say for certain. My best guesses are that the speed limits in the OSM database for these sections of the interstate are incorrect, or there is some kind of global max speed.

Due to the two-link limit, I put the links to the routes in this Google Doc: Kurviger vs. Google Maps Travel Time | Google Docs

#2

Thanks for providing more details on this.

There are a few different things to consider in this case.

Especially for high speed roads like motorways, Google has a lot of data, including statistical data for travel times and usually they are very accurate with this.

Kurviger uses data from OpenStreetMap, we don’t have statistical or live traffic data. So travel times can differ significantly.

I have added these samples to our todo list to double check and see what we can do about improving the ETA for these routes. We are constantly improving our ETA calculations, but these changes typically take a bit of time and a lot of testing, so I hope you can understand that this is not something we can change short-term.

#3

I compared two long sections. It seems that
gmaps calculates with quite exact 70 mph, while graphhopper/kurviger with quite exact 50 mph on motorways. I double checked on the graphhopper page, result as in kurviger.