Abstract: A computing device includes an interface configured to receive image data that is indicative of a field-of-view (FOV) that is associated with a head-mountable display (HMD). The computing device also includes a computing system configured to determine optical flow from the image data and to determine, based on the optical flow, whether or not the HMD is associated with operation of a vehicle. Further, the computing device is configured to control the HMD to display information in a first mode, if the HMD is associated with the operation of the vehicle, and to control the HMD to display information in a second mode, if the HMD is not associated with the operation of the vehicle.