Driving faster than the speed limit does not save much time

I was talking about this phenomenon with a friend when we were driving a couple hours on vacation and it made some sense but also didn’t make sense. Like if I am going faster than the speed limit, I would expect my estimated time of arrival on the navigation app to decrease, but it didn’t change. After reading a few articles and talking to AI, I guess it makes sense why it didn’t change. Apparently the slow parts of the trip, like traffic lights, congestion, etc. can eat up the time savings. Also, the navigation apps have historical data about the speeds of cars and current traffic data that can help power the estimated arrival time. Finally, it’s not like I’m always driving over the speed limit – my speed may change above and below the speed limit at various points in the trip. With this in mind, it gives some justification on why I usually arrive to places later than what the navigation app mentions. Like I usually drive the speed limit and if everyone on the road currently and historically are driving faster than the speed limit, then the estimated arrival time would have to adjust accordingly.