Why does "Time to Leave" in iOS Calendar suggest the wrong method of transportation?

When I have a calendar event with a location set, for some reason the iOS Calendar app always sends notification many hours earlier telling me that I should start walking now to arrive in a couple of hours. Why would I walk to destination tens of kilometers away? Why would I walk 6 hours when I can just drive there quickly? It doesn’t make sense. Preferably it would tell me when to leave by automatically checking the train times since train is my preferred method of transportation. I’ve checked under Settings > Calendar > Default Alert Times and "Time to Leave", but there’s no setting there to choose the travel type. If there’s a setting hidden somewhere else, why wouldn’t it be available here? Isn’t this the most logical place for such a setting?