Travel Control Method and Travel Control Apparatus for Vehicle

A travel control method for a vehicle, comprising:

• in a drive assist mode for assisting a driving operation of a driver using autonomous travel control including autonomously controlling traveling speed and a steering operation, setting an assist level indicating a level of intervention of the autonomous travel control in a traveling motion of the vehicle;
• and
• executing the autonomous travel control for the traveling motion on a basis of the assist level, the travel control method further comprising:
• setting at least a first assist level and a second assist level for the assist level, the second assist level being lower than the first assist level in the level of intervention of the autonomous travel control;
• and
• in a case where the assist level does not decrease from the first assist level to the second assist level while a subject vehicle is autonomously following a preceding vehicle under the autonomous travel control,
• when the subject vehicle makes a lane change from a subject vehicle lane in which the subject vehicle travels to an adjacent lane of the subject vehicle lane, detecting the preceding vehicle traveling in the adjacent lane;
• and
• prohibiting the autonomously controlling the lane change of the subject vehicle when no preceding vehicle traveling in the adjacent lane is detected.