Is anyone currently using Google's estimated travel time data accessible via their Directions API? How accurate or reasonable have you found their predicted travel times to be?
This is not really an ESRI model builder question if you are asking about google API? Suggest you or a moderator re-tag this question appropriately.
Having said that I have been using it to extract routes between locations in Turkey. I have no way of validating them but what I have noticed is that the travel times returned do not vary depend upon season. This suggests they have no historic data to predict travel times for those roads so it is defaulting to some average road speed.