For about 30 years the Insurance Institute for Highway Safety (IIHS) has used a demanding moderate-overlap frontal crash test with an adult-size dummy in the front seat to simulate a slightly offset head-on collision. That test went beyond legal minimums and helped drive dramatic improvements in front-seat protection—crumple zones, seat belts and airbags.
But as front-seat safety advanced, real-world crash data began to show an alarming trend: rear-seat occupants were increasingly at risk. IIHS analysis found that the chance of fatality in the back seat was about 46% higher than in the front. Jessica Jermakian, IIHS senior vice president of vehicle research, says that while front-seat safety has improved significantly, rear-seat protection hadn’t kept pace.
IIHS continues to advise that young children ride in the back because frontal airbags can be hazardous for them. Still, for belted teenagers and adult rear passengers—whose numbers have grown with ridesharing—rear seating can now be more dangerous than the front. To close that gap IIHS added a small, child-size dummy in the rear seat in 2022 and tightened the test criteria further in 2024.
The revised test produces striking results. At IIHS’s rural Virginia facility, a Subaru Crosstrek was accelerated to 40 mph and smashed into a concrete-and-steel barrier with an adult dummy in the driver’s seat and a 12-year-old–sized dummy in the rear. The impact was so violent the rear dummy’s hand flew out a back window, a stark illustration of rear-seat vulnerability.
When IIHS applied the tougher protocol across vehicle lines, many shortcomings surfaced. Under the new procedure, 20% fewer vehicles qualified for IIHS safety awards than under the older standard. Minivans, long regarded as family-friendly, lost ground: two that had previously earned Top Safety Pick no longer qualified under the 2025 criteria, IIHS media relations director Joe Young said.
Automakers have reacted. Hyundai provides a clear example: its Sonata scored at the lowest level on the updated test in 2023 because the rear-seat dummy showed likely head, neck, chest and abdominal injuries while the front-seat dummy was well protected. Hyundai then added rear-seat belt pretensioners and force limiters and strengthened side structure; the 2025 Sonata later achieved the highest rating under the revised test. Hyundai chief safety officer Cole Stutz said the company rose to the challenge after IIHS raised its standards.
IIHS notes that upgrading seat belts is one of the fastest changes manufacturers can make, and many have moved quickly; others are exploring deeper redesigns such as reshaped rear seats. Jermakian observes that failures can be productive—if every vehicle already passed, the test wouldn’t encourage improvements. By raising the bar, IIHS aims to spur changes that better protect rear-seat occupants and save lives.