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Shaw Chiropractic
A Medical-Legal Newsletter for Personal Injury Attorneys
by Dr. Steven W. Shaw

Research Facts on Low -Speed Rear-End Crashes on Human Subjects

To date, there have only been about 32 studies published that have used human volunteers in instrumented low-speed rear-end crashes. The lack of scientific investigation into this phenomenon on human subjects suggests that conclusions on the subject are based upon limited data. It also demonstrates the difficulty and ethical considerations associated with human research in potentially harmful investigations. Below is a summary of interesting points presented in these 32 studies.

- A total of 228 males and 49 females have been used over the past 44 yers

- None of the subjects for these studies have been randomly selected from the general population

- Most studies tested in the delta V range from 2.5-8mph.

- Occupant motion begins at approximately 100ms.

- Only 36 subjects had pre and post examinations by doctors. (Anderson 1998, Castro1997, Meyer 1998)

- None of the subjects in almost 280 crashes exceeded global range of motion at delta V 5mph.(Castro 1997, McConnell 1993)

- Many subjects were also staff members of the testing facility. (McConnell1993-1995, Scott 1993, Szabo)

- Some subjects were fitted with helmets thereby modifying test results..(West 1993)

- Most subjects were healthy before testing (McConnell 1995)

- Hybrid II and III dummies do not compare well with human subjects in low speed impacts

- Few bumpers demonstrated any damage at 5mph. (Anderson 1998)

- Honda=s demonstrated no damage after over 100 crashes.(Siegmund 1997)

- No bumper damage relationship was noted between 2.5 and 5 mph crashes. (Siegmund 1996)

- Subjects exhibited ramping (McConnell 1995, Scott 1993, Szabo 1994)

- Head turned test subjects developed pain.(Matsushita 1994, McConnell 1995))

- Forward leaning test subjects developed lower back pain.(Matsushita 1994)

- Seatback stiffness had effects on acceleration of subjects. ((Watanabe 1999)

- Head restraint vertical positioning had effect on acceleration.(Ono 1993, Watanabe 1999)

- Head restraint horizontal positioning related to head rotation. (Geigle 1994, Meyer 1998, Szabo 1996)

- Females had higher neck and head accelerations. (Siegmund 1997)

- Peak head acceleration correlated with neck circumference. (Kroonenberg 1998)

- Head restraint contact occurred in all tests.

- AUnaware@ occupants had higher accelerations. (Anderson 1998)

- All subjects, with or without symptoms, had loss of range of motion. (Brault 1998)

- Multiple tests with same delta Vs had large range of accelerations (6-12 g=s) (Siegmund 1997)

- Many subjects report moving directions different than they actually moved. (Szabo 1996)

- MRI testing after collision did not demonstrate traumatic findings (Anderson 1998, Castro 1997)

These interesting facts are best appreciated by reading the studies in their entirety. Regardless of your plaintiff or defense orientation, these studies are foundational in your understanding of human injury mechanisms.