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Estiamted time of arrival

Estiamted time of arrival


Calculation of ETA (estimated time of arrival) is hard to comprehend. It looks like the calculation improves during a ride and you have the impression that the device adopts to your riding style.

You might think that the device uses the speed average (both total and while moving) and this picuture seems to prove it (top left corner is distance to destination, top right corner is average speed while moving, lover left corner is estimated time to arrival, lower right corner is total average speed).

To understand better what happens I did a trial while riding from Cuxhaven to Berlin:

So the situation seems to be a little bit different than expected

  average speed while moving average speed total average speed remaining distance distance to destination time time to destination ETA remaining total average speed resulting from ETA deviation time deviation average speed
1 0 0 - 422 11:08 06:57 18:06 60,7 -00:01
2 76,1 73,8 63,3 365 12:18 06:01 18:19 60,7 -00:15 2,6
3 70,5 62,2 65,1 321 13:08 05:17 18:25 60,8 -00:21 4,3
4 81,5 74,6 58,1 219 14:18 04:00 18:18 54,8 -00:14 3,4
5 81,8 74,8 53,7 162 15:03 03:00 18:03 54,0 00:01 -0,3
6 78,3 69,2 55,0 111 16:03 02:00 18:03 55,5 00:01 -0,5
7 78,6 70,2 41,1 49,3 16:52 01:00 17:52 49,3 00:12 -8,2
  74,7 65,4 - 0 18:04 - - - - -

So it looks like the ETA is calculated by using average speeds for different types of roads. I do not have any other explanation for the massive change of the total average speed at the end of the journey (it included about 30 km city of Berlin). At least I did not find any other good explanation. At least the test showed:

  • the calculated ETA seems to be close to my riding style
  • the calculated ETA does not seem to be in relation to your personal average speed
  • I go quite slow within the city.