Crash-test dummies are older and fatter — just like many Americans

(CNN) Crash-test dummies need to look like real people to measure injuries in auto accidents — and for Americans these days, that means looking older and fatter.

Engineers at Humanetics, a company that manufactures crash-test dummies, teamed up with University of Michigan trauma surgeon Stewart Wang to create new dummies that have put on some pounds and carry the effects of advancing years.

Humanetics crafted two new dummies: an obese dummy that weighs 273 pounds, and a dummy that is based on an overweight 70-year-old woman. The obese dummy is more than 100 pounds heavier than a normal crash-test dummy.

“The typical patient today is overweight or obese — they’re the rule rather than the exception. You can’t talk about injuries without talking about the person,” Wang, director of the University of Michigan International Center for Automotive Medicine (ICAM), said in a statement. The ICAM team helped create the new dummies by choosing 6,000 computerized scans from a national database to provide appropriate averages to the Humanetics team, and the data was used in 3-D printing of the dummy prototypes.

“The population is getting older, and as it gets older it gets fatter as well,” Wang said. That’s why ICAM gathered data from the largest population ever, according to Wang.

Differences in body type can mean different injuries, according to Wang.

Obese drivers, for example, can “submarine” when in a frontal crash, meaning they slip underneath the lap belt. They sustain much more severe lower-extremity injuries twice as frequently as those who are not overweight. In addition, Wang estimates that drivers who suffer specifically from these injuries collectively spend $2 billion to $4 billion a year on medical bills. Since their injuries take longer to heal because of the increased weight put onto recuperating bones and tissue, the medical bills associated with those injuries can skyrocket.

In addition, growing older causes the shape of the chest to change, which causes the rate of chest injuries to increase by 15-fold. The new elderly dummy has a redesigned chest, which sags to mimic elderly drivers. It also has a weight distribution that is shifted downwards, and the spine is more curved. Elderly drivers often sustain chest-wall injuries because of the shape of the chest. Those injuries are particularly lethal because of victims’ advanced age.

Chris O’Connor, president and chief executive officer at Humanetics, based in Plymouth, Michigan, said: “Few would have envisioned that people would drive into their 80s … As the population changes, we must have test equipment that resembles consumers today.”