Although automobiles built in the past decade are much safer than earlier models, women are significantly more likely to be seriously injured in car crashes than men, even when both groups wear seat belts, according to a study published Wednesday in the journal Traffic Injury Prevention.
Specifically, the study found that women wearing seat belts are 73 percent more likely to be injured in a front-end car crash (the most common kind) than similarly belted men.
Women were particularly more vulnerable to lower-body injuries involving the legs, spine and abdomen. They were twice as likely to sustain those injuries as their male counterparts.
“Until we understand the fundamental biomechanical factors that contribute to increased risk for females, we’ll be limited in our ability to close the risk gap,” says Jason Forman, the study’s lead author and an injury prevention researcher at the University of Virginia’s Center for Applied Biomechanics, in a released statement.
How the study was done
For the study, Forman and his colleagues analyzed data from a nationally representative sample of 22,854 police-reported, front-end crashes that occurred in the United States between 1998 and 2015. The crashes involved 31,254 car occupants, ranging in age from 13 to 97 (median age: 32). They were almost evenly divided between men (49.4 percent) and women (50.6 percent).
Women more than three months pregnant were excluded from the study, as was anyone not wearing a three-point seat belt when their car crashed.
The researchers divided the crashes into two groups: those that occurred in cars manufactured before 2009 and those that occurred in cars built during or after that year. They then controlled both sets of data for factors such as the severity of the crash, the age of the vehicle and the occupant’s age, height and weight.
The data revealed that the overall risk of injury was lower among people in cars built during the past decade. There were 55 percent fewer injuries in the newer-model cars than in the older ones.
The risk was particularly lower for injuries to the skull, neck and abdomen. The risk also dropped for injuries involving the lower extremities (hips, thighs, knees and ankles). The risk of injuries to the arms and hands, however, remained the same.
Injuries to the sternum (breastbone), ribs, arms and hands were the most common injuries in both the older and newer models of cars. Older people (aged 66 and up) were particularly susceptible to injuries involving fractures of the breastbone and ribs — perhaps because their bones are more fragile, the authors of the study suggest. (Older people in the study were also more likely to have been a passenger in the car than the driver when the crash occurred.)
Interestingly, while the rate of skull injuries was lower for the occupants of newer-model cars, the rate of brain concussions was higher. That may be because awareness of concussions — and their diagnosis — has increased in recent years, say the researchers.
A lack of safety data focusing on women
The study did not explore why women sustain more serious injuries in front-end crashes than men, but study co-author Carolyn Roberts told CBC News reporter Aaron Saltzman that a major factor is the lack of safety data that focuses specifically on women.
“We’re not including females in the data analysis, in the regulatory tests, in anything we do,” said Roberts, who is a Ph.D. mechanical engineering student at the University of Virginia.
As she and other auto safety experts point out, automotive safety tests rely almost exclusively on crash test dummies that are modeled on men. In fact, many of those dummies are modeled on physically fit men who served in the U.S. military more than 50 years ago, in the 1960s.
When female dummies are used in crash tests, they tend to be just smaller versions of the male ones. That means they don’t reflect many of the anatomical and physiological differences between men and women, including differences in fat distribution, muscle strength and shape of the pelvis.
“There are just a huge number of things that suggest that females are not smaller males,” said Roberts. “… You have a three-point seatbelt. How does that sit on top of breasts? Does it move more easily if I lean out and now I have a more complicated chest geometry than a male? Is that problematic?”
Changes may be coming
The reason most crash test dummies are modeled on men apparently has to do with money. The dummies are extraordinarily complex — and thus very expensive to develop and produce.
One car company — Volvo — has been collecting safety data on women, however, and it recently announced that it will be sharing that data with other automakers as part of an initiative called Project E.V.A., or Equal Vehicles for All.
It’s a move that’s being applauded by safety experts.
“To leave out half the population and say that they can be represented by something that doesn’t really represent them is a disservice to protecting all of us in crashes,” one expert told Saltzman.
FMI: You’ll find an abstract of the study on the website for Traffic Injury Prevention. It’s important to note that the research comes with a potential conflict of interest: It was supported with a grant from Autoliv Research, a global automotive safety supplier headquartered in Sweden.