TRAVEL ASSISTANCE DEVICE, TRAVEL ASSISTANCE METHOD, AND NON-TRANSITORY COMPUTER READABLE MEDIUM

A travel assistance device includes: an inner area prediction unit predicting a with-vehicle interaction that is a behavior taken, in response to a state of the subject vehicle, by a moving object within an inner area around the subject vehicle; an outer area prediction unit predicting a with-environment interaction that is a behavior taken by a moving object according to surrounding environment of the moving object within an outer area further to the subject vehicle than the inner area; an outer area planning unit planning a future behavior of the subject vehicle based on the predicted with-environment interaction, wherein the future behavior is a behavior pattern of the subject vehicle realized by traveling control; and an inner area planning unit planning a future trajectory of the subject vehicle in accordance with the future behavior based on the predicted with-vehicle interaction.