Performance of Seating Systems in a Fmvss No . 301 Rear Impact Crash Test

Seating systems are designed for occupant comfort as well as for affording occupant protection in various crash modes. FMVSS No. 207 specifies seat performance criteria, of which, one requires that a seat back withstand a minimum of 373 Nm moment measured about the seating reference point. The sufficiency of this requirement has been a source of significant debate. Some researchers believe that the potential hazards from a seat back collapsing in a rear impact include: the inability to control the vehicle in the event of a second impact, ejection of the occupant from the seat and injury to the rear seat occupant when struck by the front seat. Molino (1998) reported that the average yield strength and average ultimate strength for all seats tested were 2.1 times and 3.4 times the current standard respectively. In spite of the greater strength of current production seats than FMVSS No. 207 requirements, there are still anecdotal cases of front and rear occupant injuries and fatalities due to seat back collapse (Saczalski, Cantor). NHTSA has in the past stated that improving seating system performance may be more complex than simply increasing the strength of the seat (57 FR 54958). Seat back force-deflection characteristics and energy management along with occupant interaction with the seat upholstery, head restraint and belt restraints may all play critical roles in mitigation of injuries in rear impacts. This paper examines the performance of original equipment manufacturer (OEM) seat systems in a series of FMVSS No. 301 crash tests of 2002 model year vehicles by using the instrumented 50 percentile male Hybrid III dummy.