A controller receives probe data from a vehicle traveling on a path segment. The probe data may be collected by a mobile device. The path segment may be a multilane roadway. The controller identifies a first lane of the path segment from the probe data. The controller associated a forked route with the first lane of the path segment. The controller calculates different traffic values for the lanes of the path segment. One traffic value may be calculated directly from speeds derived from the path data. Another traffic value may be calculated by the probe data and a historical relationship.