A method for optimizing a head-up display for the output of position-accurate additional AR information by means of a test vehicle and a test system is disclosed. The input data of the head-up display output from the vehicle bus for generating the additional AR information and video data, which include a view of the road (vehicle environment) as perceived by the driver, are recorded separately but temporally synchronized in the test vehicle. Information is generated that indicates a position where the output of the head-up display, thus, the additional AR information, is arranged in the driver's field of view. The recorded data is used for a corresponding reproduction in the test environment. This allows the head-up display software to be further developed without having to carry out test drives with the test vehicle every time the software is changed.