06362734 is referenced by 78 patents.
A system for monitoring the secured/unsecured status of seat belts in rear seating rows of a vehicle notes the number and/or location of seat belts secured at a base time when all doors are closed and the vehicle starts in motion. The vehicle operator is alerted to any later change in the number of secured belts by a visual display provided by a vehicle message center and/or an audible signal. When the vehicle slows to a stop and a door opens, the number of secured belts is reset to allow continued monitoring of rear seat occupants after occupants are dropped off and/or picked up. The secured/unsecured condition may be determined by monitoring a retractor reel of the seat belt, the secured condition being defined by the seat belt being paid out beyond a threshold length and the unsecured condition being defined by the seat belt being retracted shorter than the threshold length. Seat occupancy sensors are not required, and rear seat occupants may temporarily unfasten their seat belt as necessary to move from one seating position to another without continuous alerting of the vehicle operator.