A retrospective study in understanding 'low speed change' vehicle collisions, occupant movement and likelihood of injury

Abstract

The number of reported minor injury cases resulting from road traffic collisions appearing before the courts in the United Kingdom was in excess of 500,000 in 2007. Over 430,000 of the claims presented to the Courts were for ‘whiplash’ injuries. Whilst whiplash is in fact a
mechanism for injury and it is acknowledged that the term almost exclusively relates to soft tissue injury. The United Kingdom is referred to as the whiplash capital of Europe, with 75% of personal injury claims being for whiplash. The cost to the NHS for consultation fees etc
for treating whiplash injuries is approximately £8 million annually. It has been felt for some time that the number of reported injury cases cannot all be legitimate. There is a large number which falls under the category of ‘Insurance Fraud’. Such is the problem that the Transport Select Committee has been considering how to tackle it now for a number of months. The applicant has personally provided assistance to the Chair of the Committee.

The question: ‘How do experts assist in determining the legitimacy of individual cases?’ has been addressed by this study. The research in this thesis (which consisted of both full scale crash testing and simulator testing) is based on a simplification of both the classification and
understanding of low speed change collisions. Rather than considering a threshold below which individuals are not injured, it was felt that classification would be a much simpler way of defining the nature and magnitude of specific cases when comparing occupant acceleration
in collisions with accelerations encountered in daily activity. Indeed, such an approach could also lead to less conflict with the legal system where the two disciplines meet, especially since the expert must not usurp the duty of the Court.

It was initially considered that there must be a threshold (i.e. a speed change) below which injury cannot occur to motor vehicle occupants. Indeed, this has been the position of some insurers and researchers for a number of years. The work presented in this thesis is both retrospective and current and it spans an 8 year period. At the inception of the study, it was clear that attempting to find a threshold in the manner of ‘one size fits all’ would be difficult
and likely would be impossible, especially since all drivers and passengers in cars are individuals.

International opinion seems to be in favour of the 5 mph 'threshold' of human occupant injury tolerance within the typical time frame of a rear end collision. However, the results from this study (after recording transient symptoms and a lengthy follow up period) have revealed that
speed changes at this level produced considerably greater levels of average acceleration than any normal daily activity and provided much higher peak acceleration levels when considering the disparity between head and chest response.

From these initial results it can be concluded that speed changes above 5 mph provide accelerations at a level considerably beyond those experienced in daily activity. The results also show that speed changes below 3 mph provide accelerations at a level generally experienced throughout daily activity and easily tolerated by human beings. That is, normal daily routine ranging from sitting in a chair to light non-contact sport at the upper level etc. The accelerations experienced in speed changes between 3 mph and 5 mph would obviously fall within the two parameters.

Analysis of the numerous tests of varying types undertaken lead to the conclusion that there is no one type of ‘everyday activity’ test that accurately replicates a rear end collision. The simulator and crash tests are the only way to accurately measure accelerations and understand
what actually happens.