A new crash test metric designed to measure rotational brain injuries is set to enhance vehicle safety evaluations, the Insurance Institute for Highway Safety (IIHS) announced. The metric, known as Diffuse Axonal Multi-Axis General Evaluation (DAMAGE), has already been used in the National Football League (NFL) for helmet safety assessments and is now being applied to automotive crash tests.
Currently, vehicle crash ratings rely on the head injury criterion (HIC), a measurement that assesses the risk of skull fractures from direct impacts. However, HIC does not account for rotational motion -- similar to the head-whipping effect seen in high-impact sports or boxing -- which can lead to concussions and other traumatic brain injuries.
DAMAGE offers a more comprehensive evaluation by capturing these rotational forces, providing insights into injury risks that were previously undetected.
“Modern vehicles do an excellent job of protecting occupants from direct head impacts, but in some cases, the head can whip to the side after striking an airbag, leading to injuries that HIC alone doesn’t fully capture,” the IIHS explained in its announcement. “With DAMAGE, we can identify these injury risks and explore potential improvements to airbag designs.”
IIHS researchers tested DAMAGE on 800 crash test dummies across multiple crash scenarios. In most cases, the new metric aligned with existing criteria, confirming the dummy’s head was well-protected. However, in about 60 cases, DAMAGE revealed potentially dangerous rotational motions that were previously overlooked.
Unlike earlier rotational injury measures, such as the Brain Injury Criterion (BrIC), DAMAGE considers the timeline of successive impacts rather than treating them as simultaneous events. This allows for a more accurate representation of real-world crash dynamics.
The European New Car Assessment Program has been using DAMAGE in its safety ratings since 2022, and IIHS is now laying the groundwork for its inclusion in U.S. safety assessments.
One potential solution to reduce rotational injuries is the development of deeper, softer frontal airbags that create a “catcher’s mitt” effect, cradling the head instead of allowing it to slide off and whip to the side.
Although DAMAGE scores are not yet included in IIHS crash test ratings, the institute has begun incorporating them into technical reports, encouraging automakers to explore new safety measures.
Vehicle manufacturers are urged to take proactive steps in addressing rotational brain injuries, even before the new metric becomes a formal part of safety evaluations.
“Starting this year, DAMAGE scores will be calculated for all crash tests, and the results recorded in our technical reports,” IIHS stated. “Automakers don’t need to wait to start looking for ways to prevent the head-whipping motions that DAMAGE reveals.”
