Regardless of whether crash sensors are mounted in the crush zone or non-crush zone, there will always be crashes where the sensors trigger late and the occupant has moved to a position near to the airbag deployment cover where he or she may be injured by the deployment of the airbag. The required sensor triggering time is now determined by assuming that the occupant is a 50% male sitting in the mid seating position. 70% of vehicle occupants are smaller and, on average, sit closer to the airbag and thus are even more likely to be out-of-position. Finally, current sensor systems make no allowance for occupants that are wearing seatbelts, for rear facing child seats located on the front passenger seat or for unoccupied seats. There are thus strong safety reasons for occupant position sensors.
This paper discusses the above problems, the difficulties in sensing occupants and objects located in the vehicle and attempts to define the requirements for such devices. It also presents some of the added benefits which will result from effective sensors which can characterize the contents of the vehicle such as heating, air conditioning and entertainment systems which adjust to vehicle occupants.