This morning I was caught in a traffic jam in which we traveled 1 mile in 24 minutes. The app was showing travel speed for the area of 8-12 mph at the time because of the number of vehicles exiting the traffic jam to turn around or cutting out of the traffic through side streets. This causes inaccuracy in the eta and may have resulted in routes 'b' or 'c' being faster. Since the GPS is estimated based on location is it not possible to make a change to the system that removes one car length of distance from the speed calculation for each vehicle turning a full 180 degrees to back track.