VEHICLE WAS TRAVELING STRAIGHT ON HIGHWAY WHEN ON COMING VEHICLE DRIFTED INTO OUR LANE. HEAD ON COLLISION ENSUED. REAR PASSENGER SEAT BELT ANCHOR BROKE DURING ACCIDENT RELEASING THE BELTED PASSENGER WHO SUFFERED BLUNT TRAUMA AND WAS KILLED. THE ACCIDENT WAS AT UNDER 45 SPEEDS AND THE FRONT PASSENGER AND DRIVER OF THE ONCOMING TOYOTA CAMERY SURVIVED WITH NO LIFE THREATENING CONDITIONS.