Abstract: A processing method implemented by a host mobile object includes steps of: monitoring a target mobile object traveling in an oncoming lane; and upon determining that the target mobile object traveling in the oncoming lane is detected, selecting, as driving control given to the host mobile object according to an overlapping travel situation where a future travel of the host mobile object and a future travel of the target mobile object would overlap with each other in the oncoming lane, either (i) deviation control for the host mobile object to deviate from the host lane to the oncoming lane or (ii) standby control for the host mobile object to stay in the host lane.