CONTROL DEVICE AND CONTROL METHOD FOR RIDER ASSISTANCE SYSTEM

The present disclosure provides a controller and a control method capable of assisting a rider in driving a straddle-type vehicle to which mounting of a surrounding environment detector is difficult.A first straddle-type vehicle (200) has a first rider-assistance system (110) that is configured to assist a first rider (101) in driving a first straddle-type vehicle (200) and has no surrounding environment detector. A second straddle-type vehicle (100) has a second rider-assistance system (10) that is configured to assist a second rider (1) in driving the second straddle-type vehicle (100) and has a surrounding environment detector (11). The first rider-assistance system (110) receives information, which is based on surrounding environment information of the second straddle-type vehicle (100), from the second rider-assistance system (10) directly or indirectly by wireless communication and executes a rider-assistance operation to assist with the first rider (101) based on the information.