CONTROLLER, METHOD, AND COMPUTER PROGRAM FOR VEHICLE CONTROL

A vehicle controller includes a processor configured to: determine a driving plan when a lane change from a host vehicle lane to another lane is requested. The driving plan represents travel behavior of a vehicle until completion of the lane change and satisfies a safety condition that the vehicle will collide with none of objects around the vehicle detected from a sensor signal obtained by a sensor mounted on the vehicle. The processor is further configured to: set a completion condition indicating a position or time at which the completion of the lane change is required, determine whether the completion condition is satisfied when the vehicle is driven according to the driving plan, control the vehicle to make the lane change according to the driving plan when the completion condition is satisfied, and restrict execution of the lane change when the completion condition is not satisfied.