For three decades the Insurance Institute for Highway Safety (IIHS) has been crashing vehicles with an adult-sized dummy in the front seat to simulate a moderate overlap frontal collision. Those tests went beyond legal minimums and pushed automakers to improve front-seat protection.
As front-seat safety advanced — better crumple zones, smarter seat belts — real-world data showed a surprising shift: rear-seat occupants were becoming more likely to be fatally injured. IIHS found the risk in the back seat was 46% higher. Jessica Jermakian, IIHS senior vice president of vehicle research, says the field data made clear the rear hadn’t kept pace with front-seat improvements.
IIHS still advises that young children ride in the back because of airbag risks. But for teens and adults wearing seat belts — and with more adults riding in back because of ridesharing — the back seat is now comparatively riskier. In response, IIHS added a child-sized dummy in the rear seat in 2022 and tightened the moderate overlap frontal test again in 2024.
The updated test can be stark. At an IIHS facility in Virginia, a Subaru Crosstrek was propelled into a barrier at 40 mph with an adult dummy in the front and a 12-year-old-sized dummy in the rear. The crash was violent enough that the child dummy’s hand was thrown out the rear window — a moment that left observers visibly shaken.
The tougher test has exposed shortcomings quickly. Under the revised criteria, 20% fewer vehicles qualified for IIHS safety awards. Minivans — long seen as family-friendly — lost ground: none earned Top Safety Pick in 2025, primarily due to weak rear-seat performance.
Some automakers have responded fast. The Hyundai Sonata received the lowest rating on the updated moderate overlap test in 2023 because the rear-seat dummy showed likely head/neck, chest and abdominal injuries, even though the driver was well protected. Hyundai added rear-seat pretensioners (which tighten belts instantly in a crash), force limiters (which add measured slack later), and side-structure improvements. The 2025 Sonata earned the highest rating on that test. Hyundai’s chief safety officer, Cole Stutz, said the company “stepped-up to the challenge.”
IIHS media relations director Joe Young notes similar rapid improvements across other models. Jermakian says upgrading rear seat belts is a change automakers can make quickly; manufacturers are also exploring more complex redesigns, such as reshaping rear seats.
For IIHS, many vehicles failing the tougher test is partly positive: when all vehicles score highly on a given test, the test no longer pushes safety forward. Raising the bar aims to spur the next wave of improvements so rear-seat occupants get protection closer to what front-seat passengers now enjoy.