Google Maps provides a feature to estimate your arrival time based on typical traffic along your route. It provides this time as a range, e.g., "typically 1h - 1h 50m" Based on that, if you select to arrive at a specific time (vs. leave now or depart at), it will tell you what time to leave given the high end of the range.
My question is: if you follow the advice and leave yourself the high end of the estimated travel time range (1h 50m in my example above), how likely are you to arrive at your destination on time?
This is a rewording of this closed question: How is the range of Google Maps new drive time feature defined?