What speed does Google Maps use for drive time calculations?

These things range from official speed limits and recommended speeds, likely speeds derived from road types, historical average speed data over certain time periods (sometimes just averages, sometimes at particular times of day), actual travel times from previous users, and real-time traffic information. read more

It is a complex calculation based on numerous factors. Some of which I can guess are, * legal speed limit in roads along the route * Traffic condition - present and predicted * Average speed of users along the route in past. read more