Benefits of Active Head Restraints for Compliance to Rear Impact Test Requirements 2007-01-0371
The International Insurance Whiplash Protection Group (IIWPG) rating system has driven improvements in head restraint (head restraint) geometry and the addition of a dynamic test has helped address head restraint construction parameters. FMVSS 202a Static imposes more stringent requirements on backset and stiffness and the Dynamic option relaxes the potentially uncomfortable backset requirement if angular head movement can be limited to a specified level.
These two requirements utilize different crash dummies and measurement parameters. The BioRID2 ATD (IIWPG) rewards a seat with good torso penetration to reduce neck loading. Seats with high comfort content tend to rate low. The Hybrid III-50 ATD (FMVSS) rewards limited lower torso penetration to reduce head rotation relative to the torso.
Current production seats without active head restraints (AHR) are difficult to optimize to meet both the requirements of FMVSS 202a Dynamic and earn an IIWPG rating of Good. The IIWPG rating may be degraded in order to satisfy FMVSS. However, a good AHR design can meet FMVSS 202a Dynamic and earn IIWPG Good.