A vehicle safety device for insuring that occupants of a vehicle are wearing a seat belt that includes a gear shift interlock mechanism including a locking mechanism for engaging the gear shift lever of a vehicle which is controlled by a controlling having a sensor provided on each of the seats of a vehicle. When the sensor generates a signal indicating that a person is seated on the seat, the controller waits to receive a buckling signal from the seat belt before allowing the user to move the gear shift. If the buckling sensor does not detect a buckling after the weight sensor is triggered then the locking mechanism does not unlock until the seat belt unbuckled and then rebuckled.