Threshold determining means determines {HEAD ~ a velocity threshold value} functionally related to {TAIL ~ the crash displacement value} 
functionally related to
Threshold determining means determines { HEAD ~ a velocity threshold value } functionally related to { TAIL ~ the crash displacement value }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL