Carolyn Roberts

By Carolyn Roberts
2017 Recipient of Best Presentation at AAAM’s Student Symposium

In 2011, Bose et al¹ found that females are 47% more likely to sustain severe or fatal injuries in a given car crash compared to males, even after controlling for age, height, weight, and the severity of the crash. Why?  What is it that makes females more likely to be injured?

The answer is simple: males and females are different.  However, understanding how differences between males and females affect the likelihood of injury, and occupant protection in a car crash, is much less simple.

Differences between the sexes

Bone shape, ligament and tendon material properties, amount of cartilage on bones, and joint range of motion all tend to be different between males and females. These are biological differences between the sexes, which might affect the mechanical response of the body when it experiences an automotive crash.  Which one of these differences contributes the most to injury?  No one knows for sure. So why haven’t we figured it out yet?

A little bit of history

While automotive safety has been a public health concern since the 1930s, most of the biomechanical reference data has been generated targeting male occupants. Initially, this made sense: at the time, most drivers were male, and some of the first crash dummies were developed for military use. With automotive safety in its infancy, any improvement in male safety also improved female safety; the field was just learning how to protect humans as a whole.  However, over time, automotive safety has become much more successful in protecting vehicle occupants, and now the bias in our male reference data has become a problem.  Females make up a majority of the population (almost 51%), are more likely to live longer, and are just as likely to be in a vehicle as a male. Females also have a higher risk of being injured when in a collision. Still, the most commonly used crash test dummies and the most advanced computational models used by manufacturers worldwide are almost entirely built based on male-focused data.

Trying to bring car safety to an equal playing field

So what do we need to do to address the data gap between the sexes?  Do we have to repeat all of the biomechanics research that has been performed for males over the last 90 years, targeting females instead?

No. Males and females are different, but they’re still human.  Because of their common human-ness, it’s likely possible to leverage the male data that we’ve already collected, and our growing knowledge of the fundamentals of biomechanics, to predict female responses using advanced modeling tools. To do that well, however, we need an in-depth understanding of the biomechanical differences between males and females, and how those differences relate to injury.

And that’s where we are today. Research is ongoing across many different fields to understand the basic biomechanical differences between males and females. As we build this base of knowledge, this information can be incorporated into tools of increasing sophistication to translate between historically male-focused data and accurate injury prediction for females. In the future, both male and female injury prediction tools will be available for automobile manufacturers and injury prevention researchers to make vehicles safer across the population.

1. Bose, D., Segui-Gomez, ScD, M. and Crandall, J.R., 2011. Vulnerability of female drivers involved in motor vehicle crashes: an analysis of US population at risk. American journal of public health, 101(12), pp.2368-2373.