For three decades the Insurance Institute for Highway Safety (IIHS) has run a demanding moderate-overlap frontal crash test with an adult-size dummy in the front seat, simulating a slightly offset head-on collision. The test exceeded legal minimums and pushed automakers to improve front-seat protection.
But as crumple zones, seat belts and other front-seat protections improved, real-world data showed a troubling shift: fatalities became more common for rear-seat occupants. IIHS found the risk in the back seat was 46% higher. Jessica Jermakian, IIHS senior vice president of vehicle research, says, “What we saw when we went back and looked at the field data is that while we’ve made lots of improvements for the front seat, the rear seat hadn’t kept pace.”
IIHS still recommends younger children ride in the back seat because frontal airbags pose unique risks to them. However, for seat-belted teenagers and adult rear passengers—whose numbers have risen with ridesharing—the back can now be riskier than the front. To address that gap, IIHS added a small, child-size dummy in the rear seat in 2022 and further tightened the test criteria in 2024.
The updated test is visceral. At IIHS’s rural Virginia facility, a Subaru Crosstrek was accelerated to 40 mph and slammed into a concrete-and-steel barrier. An adult dummy in the driver’s seat and a 12-year-old–sized dummy in the rear were belted in. The crash was so violent the child dummy’s hand flung out a rear window—an image that underscored the rear-seat dangers.
The tougher test quickly exposed shortcomings across vehicle lines. Under the updated procedure, 20% fewer vehicles qualified for IIHS safety awards than under the older, less-stringent version. Minivans, long seen as family-safe vehicles, lost ground: where two had once earned IIHS’s Top Safety Pick under the old test, none did in 2025 because of poor performance in the revised moderate-overlap test, IIHS media relations director Joe Young said.
Manufacturers have responded. The Hyundai Sonata illustrates rapid improvement: in 2023 it earned the lowest possible rating on the updated test because the rear-seat dummy showed likely injuries to the head or neck, chest and abdomen while the driver remained well protected. Hyundai added rear-seat belt pretensioners (which tighten belts immediately in a crash) and force limiters (which give controlled slack moments later), and strengthened side structure. The 2025 Sonata then scored the highest possible rating on the updated test. Hyundai’s chief safety officer, Cole Stutz, told NPR that after IIHS announced stricter testing, “Hyundai stepped-up to the challenge,” implementing advanced seatbelts and structural changes.
IIHS notes that seat-belt upgrades are among the fastest changes automakers can make, and many manufacturers have moved quickly. Others are pursuing more involved redesigns, such as reshaping rear seats. Jermakian says flunking vehicles can be a positive sign: if every car already aced a test, it wouldn’t push companies to improve. Raising the bar, she argues, spurs safety advances for rear-seat occupants that can save lives.
