User interface for predictive traffic

A navigation device includes a predictive traffic data database to store predictive traffic data at a plurality of times and a map database to store mapping data. A mapping module calculates a route and an estimated time of traversal for a route between a beginning geographic location and an ending geographic location based on the predictive traffic data and the mapping data. A start time modification module monitors for a modification of a start time for the route, with the mapping module re-calculating the estimated time of traversal in response to the modification of the start time for the route.