A trusted co-server, and a method of using a trusted co-server, for a service provider. If it is judged that the front road-shape is not covered by the first illumination range beforehand, the second control circuit controls the actuator to cover the road-shape by the second illumination range. The transmissible light member includes a body portion and a patterned portion protruded from the body portion. Systems, graphical user interfaces, and machine-readable media are also provided.