A variable velocity threshold value is determined in {HEAD ~ response} to {TAIL ~ the determined crash displacement value} 
to
A variable velocity threshold value is determined in { HEAD ~ response } to { TAIL ~ the determined crash displacement value }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL