"Women have different physiology, less muscle structure, a different bone structure and different fat distribution," he said. "It is important to test for difference sizes of occupants and also to understand how they respond differently to different injuries."
The female dummy is designed with sensors where women are most vulnerable to injury in a car crash, such as the neck, legs and abdomen. It also has a lower pelvis than the male dummy, which is important in measuring how a seat belt engages differently with a female in a car crash.
Despite the differences, automakers only need to pass federal crash safety tests with a standard male dummy at 5 feet 9 inches and weighing 171 pounds. That standard was set in the 1970s, when the average man weighed less.
NHTSA did not introduce female dummies, which are just scaled-down versions of the male, into crash tests until 2003. And at 4 feet 11 inches and weighing 108 pounds, they are also significantly smaller than today's average female.
There has been a recent push to address the inequality in crash safety tests. U.S. Rep. Brenda Lawrence, D-Southfield, and 65 other House members sent a letter last year to the Department of Transportation, urging it to update crash-test standards.
"We write to call your attention to an often-overlooked inequity in the area of vehicle safety: the gender-based discrepancies in traffic injuries and fatalities that are in part attributable to the absence of female crash test dummies in the current crash test system," the letter said. "Ultimately, omitting crash test dummies that reflect women inhibits complete information gathering and produces inaccurate vehicle safety performance evaluations."
NHTSA said it plans to issue new proposed regulations with specifications for a new female crash test dummy in the next year.
"Gender disparities in outcomes of traffic crashes are unacceptable, and NHTSA is dedicated to solving this problem using all the tools it has — including ensuring stronger safety standards and an updated and more effective set of NCAP standards, as well as using high-quality computer simulations and crash dummies," the administration said.
Even as regulation lags the technology available, Humanetics is working on newer generations of dummies that it predicts will become the standard years down the road. It has poured millions of dollars into prototyping THOR AV, a dummy designed with a flexible pelvis to accommodate multiple body positions within an autonomous vehicle.
"The industry knows that they need a solution for autonomous vehicles where you've got people reclining or sitting backwards," Loehnis said.
On the computer side, the technology is evolving beyond digital dummies used in simulated crash tests. Engineers are now starting to model the actual human body. While the process is complicated and time consuming, it is expected to eventually be done at scale, Loehnis said.
"I think we see the digital and physical as growing together," he said. "You'll always need a physical validation of your simulation."