An experiment was conducted to compare the effectiveness of head restraints modified to increase the likelihood of eliciting uninstructed adjustments from a non-use to a deployed position among naive users. Fifty-nine participants aged 18-46 years experienced one of three head restraint conditions. The first condition consisted of an unmodified, original equipment (OE) secondrow head restraint from a 2009 Ford Flex, which was compliant to specifications in the United Nations Global Technical Regulation (GTR) No. 7 intended to provide distinct physical cues to alert occupants to the need to adjust the head restraint. The second condition consisted of an OE head restraint modified to be longer vertically, which also met the GTR specifications. Lastly, a thicker head restraint producing a torso angle change of 10 degrees from the seat back (10 degrees), one of multiple compliance options allowed in FMVSS No. 202, was examined. Participants were asked to enter the drivers side rear seat of a vehicle for the stated purpose of being driven to another site to participate in a different experimental protocol. During the brief ride between the two locations, the participants responses to the stowed head restraint were recorded by a hidden video camera. Video records were analyzed to identify observable evidence of discomfort and participants attempts to reposition the head restraint from a non-use to a deployed position. Effectiveness of the physical cue was defined as the percentage of occupants that showed discomfort and/or moved the stowed head restraint to a deployed position without specific instruction. Fourteen of 22 passengers (64%) in the 10-degree condition made some attempt at adjustment, compared to 3 of 19 (16%) in the Lengthened OE and 0 of 18 (0%) in the baseline (OE) condition. Differences in the adjustment rates between the 10-degree and other two conditions were statistically significant. 79% of participants in the 10-degree condition adjusted the restraint immediately after securing the seat belt. The results of the study indicate clearly that the 10-degree head restraint was significantly more effective than the OE or lengthened OE restraints in motivating adjustment attempts by participants. The results of the present study were consistent with those of the previous study.
Effectiveness of Rear Seat Head Restraint Non-Use Position Discomfort Indicators
2011
40 pages
Report
No indication
English
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