A remark on that: during our vacation (cycling) the ETA often was not really usable. Reason: the topography of the route has a huge influence on the speed you are able to ride. Consider a tour where you go uphill the first half and downhill on the second. Just considering the current average speed, would result in unusable results,because it would estimate going up the whole tour. But this is wrong, since the second half will be faster because it is downhill.
I think the ETA algorithm (for cycling and probably also for hiking) should work somewhat like the algorithm to estimate the time for a track. The current avg speed could\should be used to set the parameters for that estimate (like piking the best profile in the trip time estimate).
I think the ETA algorithm (for cycling and probably also for hiking) should work somewhat like the algorithm to estimate the time for a track. The current avg speed could\should be used to set the parameters for that estimate (like piking the best profile in the trip time estimate).