In the recent years, a large effort has been directed towards the investigation of injury mechanisms and injury tolerance criteria related to whiplash associated disorders (WAD). Nevertheless, many questions, especially related to injury criteria and their respective biomechanical tolerance levels, remain unresolved. With the introduction of consumer tests in which the protection potential of seats against WAD is evaluated, a discussion of the criteria used for these ratings is needed, since for most proposed WAD injury criteria, e.g. NIC, Nkm, no widely accepted tolerance levels or even accurate injury risk curves are available today. One of the often disregarded points in the tolerance limit discussions is the fact that most injury criteria values have a non-linear relation to injury risk. Many tolerance levels for criteria related to injuries other than WAD (such as HIC, Nij, TTI, TI etc.) were derived using highly non-linear logistic regression curves. The biomechanical loads discussed in conjunction with WAD, e.g. accelerations, forces, torque, are generally very low in comparison to loads acting in other crash situations. Therefore, even minor changes in a test set-up may result in significant changes in the loads measured. Furthermore, issues of repeatability and reproducibility become more important in these low-load test conditions.

A series of sled tests was conducted to assess the influence of several test parameters on the repeatability of results obtained with the BioRIDIIg Dummy. The sled tests were performed according to the test procedure proposed by EuroNCAP. The results show that some criteria like the neck shear force exhibit variations up to 30%. The influence of such deviations has to be considered when introducing a reliable rating system for WAD.