The routing server uses real-time road speeds (from recent Waze app users if available) and combines the historical speed of the segment broken down into 10-15 minute chunks. The time to pass through a segment is tracked separately for each route out of a segment. For example if a segment ends with a left and right turn (no straight let's say), then the routing engine isolates the time through the segment to turn left and the time through the segment to turn right. This detailed speed information is proprietary & is part of the data Waze sells/plans to sell and won't be displayed through the editor.