A system may receive head pose indications determined according to movement data from a motion sensor of an optical head-mounted display worn by a vehicle driver, determine, according to the head pose indications, driver activity characteristics indicative of a history of movement of the head of the driver, and send the driver activity characteristics to a driver-aware vehicle system configured to adjust driver notification based on the driver activity characteristics. The system may also receive raw movement data from a motion sensor of an optical head-mounted display worn on a head of a vehicle driver, compute head velocity data based on the raw movement data, compute head displacement data based on the head velocity data, and update head pose indications indicative of head positioning upon determining that the head displacement data exceeds a predetermined threshold displacement.