TRAVEL ASSISTANCE METHOD AND TRAVEL ASSISTANCE DEVICE

A travel support method for a vehicle to be executed by a processor, comprising, estimating a position of a subject vehicle, acquiring map information from a database, generating a subject vehicle traveling route on which the subject vehicle travels, based on the estimated position of the subject vehicle and the map information, calculating a degree of first reliability indicating reliability of the subject vehicle traveling route, detecting a preceding vehicle traveling ahead of the subject vehicle, generating a preceding vehicle traveling route on which the preceding vehicle travels, calculating a degree of second reliability indicating reliability of the preceding vehicle traveling route, based on a shape of the preceding vehicle traveling route, calculating, based on the degree of the first reliability and the degree of the second reliability, an integration ratio for integrating the subject vehicle traveling route and the preceding vehicle traveling route, calculating a target traveling route of the subject vehicle by integrating the subject vehicle traveling route and the preceding vehicle traveling route at the calculated integration ratio, and controlling the subject vehicle based on the target traveling route.