title: The RID2 biofidelic rear impact dummy: a pilot study using human subjects in low speed rear impact full scale crash tests.
abstract: METHODS
  Human subjects and the recently developed RID2 rear impact crash test dummy were exposed to a series of full scale, vehicle-to-vehicle crash tests.
  
  
  OBJECTIVE
  To evaluate the biofidelity of the RID2 anthropometric test dummy on the basis of calculated neck injury criterion (NIC) values by comparing these values to those obtained from human subjects exposed in the very same crashes.
  
  
  BACKGROUND
  The widely used and familiar hybrid III dummy has been said to lack biofidelity in the special application of low speed rear impact crashes. Several attempts have been made to modify this dummy with only marginal success. Two completely new dummies have been developed; the BioRID and the RID2. Neither have been tested under real world crash boundary conditions in side-by-side comparisons with live human subjects.
  
  
  METHODS
  Volunteer subjects, including a 50th percentile male, a 95th percentile male, and a 50th percentile female, were placed in the driver's seat of a vehicle and subjected to a series of three low speed rear impact crashes each. The RID2 dummy, which is modeled after a 50th percentile male, was placed in the passenger seat in each case. Both subjects and dummy were fully instrumented and acceleration-time histories were recorded. From this data, velocities of the heads and torsos were determined and both were used to calculate the NIC values for both crash test subjects and the RID2.
  
  
  RESULTS
  The RID2 demonstrated generally higher head accelerations and NIC values than those of the human subjects. Most of the observed variations might be explained on the basis of differing head restraint geometry, posture, and body size. The RID2 NIC values compared most favorably with those of the 50th percentile male subject. For the whole group, the correlations between RID2 and human subjects did not reach statistical significance.
  
  
  CONCLUSIONS
  The small number of test subjects and crash tests limited the statistical power of this pilot study, and the correlation between the RID2 and human subject NIC values were not statistically significant. The overall qualitative performance and biofidelity of the RID2 was reasonable when compared with the male human 50th percentile subject. Its overall higher ranges of head acceleration and calculated NIC values compared to all of the human subjects were generally consistent. This condition could likely be improved by increasing the stiffness of the RID2 neck. Biofidelic validation of the RID2 will require ongoing testing using a larger number of human subjects and varying boundary conditions. The results of this pilot study, while encouraging, should be considered preliminary.
authors.affiliation: Spine Research Institute of San Diego, Southern California University of Health Sciences, Center for Research into Automotive Safety & Health, United States. drcroft@srisd.com
authors.forename: Arthur C
authors.initials: AC
authors.lastname: Croft
authors.forename: Mathieu M G M
authors.initials: MM
authors.lastname: Philippens
mesh_terms: D000054:Acceleration; D000063:Accidents, Traffic / Q000706:statistics & numerical data; D001696:Biomechanical Phenomena; D006801:Humans; D008348:Manikins; D010865:Pilot Projects; D015203:Reproducibility of Results; D014911:Whiplash Injuries / Q000209:etiology / Q000503:physiopathology*