Plus-size models might still be derided by the fashion set but they're exactly what the doctor ordered where car safety tests are concerned. With obesity rates rising worldwide and the boomer generation getting older, a Michigan-based trauma surgeon and crash-test-dummy manufacturer are hoping to bring car safety up to date with models that are a more accurate representation of today's older and overweight drivers.

"The typical patient today is overweight or obese – they're the rule rather than the exception," says trauma surgeon Stewart Wang, an expert in crash-related injuries who heads the University of Michigan's International Center of Automotive Medicine (ICAM). He had noticed changes in the patterns of car injuries years ago and what caught his attention was the fact that some of them were due to design flaws that arose from using dummies that looked "nothing like my patients [or] the population these days."

His observations, together with data about human bodies based on the analysis of real-world crashes, helped pave the way for the development of Humanetic's (the dummy-making company) latest crash test models: a 273-pound obese dummy with a Body mass Index (BMI) of 35 that is 103 pounds heavier than the traditional standard model, and an elderly dummy with a BMI of 29. Based on a 70-year-old overweight woman, the latter's torso and chest have been substantially redesigned to reflect the sag that comes with age – according to Wang, as the structure of the chest changes from one's 20s to 80s, the risk of chest injury increases fifteen fold. It also comes with a newly designed organ system concept to allow more precise measurements of internal injuries sustained in car accidents.

Humanetics CEO Christopher O’Connor and Michigan Medicine trauma surgeon Stewart Wang with the new elderly crash test dummy(Credit: Bryan McCullough/Michigan Medicine)

While these details might seem trivial, what many people do not realize is that the severity of injuries sustained in a crash is dependent on the condition, size and shape of the individual. This is why it is important for dummies to reflect the bodily proportions of today's drivers, who have gotten heavier and older.

"When you select a car and you look at the five-star crash rating or the insurance institute rating scheme, you assume that it's the same for all drivers but in fact it may not be because your body size may react differently from the restraints, airbag, seat belt or even to the seat itself. As a result, it might be less safe for you," explains Humanetics CEO Christopher O'Connor in an interview with a Detroit TV station.

The obese dummy in red has a BMI of 35. According to the Centers for Disease Control and Prevention, a BMI that is 30 or higher falls in the obese range (Credit: Bryan McCullough/Michigan Medicine)

And unfortunately for obese drivers, the odds are not in their favor of surviving a car crash. According to a study conducted by the University of California, Berkeley, up to 78 percent of them are at greater risk of dying in a car crash compared to normal-weight drivers. The higher one's BMI, the higher one's risk of death, a danger that remains even when a driver is wearing a seat belt or the air bag is deployed. This is due to the fact that the safety features that are designed to protect normal-weight vehicle occupants are inadequate for overweight vehicle occupants, suggest the authors of the Berkeley study. Indeed, those who survive an accident often end up sustaining severe injuries.

Since obese drivers have a lot of body mass in the top, they tend to "submarine" underneath the lap belt, (i.e. slide under since their lower bodies are poorly restrained by the slack belt), explains Jim Davis, VP of engineering at Humanetics. "As you do so, you can develop a lot of lower extremity injuries that may keep you out of work and take longer to recover from."

Elderly drivers are also another growing cause for concern. In the US alone, there are currently more than 40 million licensed drivers aged 65 and older, a development that few car safety engineers could have imagined in the 1970s. More than 5,700 elderly drivers were killed and more than 236,000 treated in emergency departments for crash injuries in 2014, a number that's equivalent to a daily average of 16 older adults killed and 648 injured.

Getting to market - road bumps ahead

That said, some industry observers, such as Russ Rader, a senior executive at the Insurance Institute for Highway Safety, remain sceptical about the ability of these new dummies to address the problems faced by obese drivers. In his opinion, a different dummy doesn't change the basics of crashworthiness. "The key to performing well in the IIHS tests is keeping the vehicle's occupant compartment intact," he says in an interview with automotive industry researcher Edmunds.com. "If the occupant compartment stays together and resists intrusion, then the safety belts and airbags can do their jobs well. A different dummy wouldn't change the fact that some people are at a higher risk in crashes than others."

Apart from sceptics, there's also the fact that getting the National Highway Traffic Safety Administration (NHTSA), the federal agency responsible for promoting traffic and motor vehicle safety, to include these new dummies in its current family is a process that can best be described as glacial. It can take as long as 10 years for a new dummy to be introduced after all the tests and evaluations have been completed. Indeed, its most recent one was in 2012, when it included a dummy representing a ten-year-old child to evaluate child safety seats and boosters designed for those weighing more than 65 pounds. So far, despite all the statistics highlighting the risks that obese drivers face, all has been quiet on the NHTSA front regarding the new obese - and presumably elderly - models. We've reached out to Humanetics for clarification on this situation but so far, it looks like it will take time before these new models become a regular fixture in safety crash tests.

The future of car safety

That said, all is not lost. As Wang himself points out, "There's no new single safety device that will markedly improve driver safety." As technology advances, there will be other developments to raise the bar for vehicle safety higher. These include the development of adaptive restraint systems that let drivers control variables such as seat-belt tension, as well as when and how much an airbag inflates. To further improve pedestrian safety, cars might also come with modifications that reduce their risk of being pinned under a car in the event of accidents.

For his part, Wang is interested in seeing whether recently introduced center airbags, which inflate between the front seats, can reduce the number of side-impact crashes between passengers and drivers. "Oftentimes, the most severe injuries come not from the striking vehicle but the other occupant flying across and hitting the [person nearest to him]," he observes.

Source: University of Michigan

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