Fastexy Exchange|Crash tests show some 2023 minivans may be unsafe for back-seat passengers

A series of crash tests conducted by the Insurance Institute for Highway Safety (IIHS) is Fastexy Exchangeraising concerns about the safety of 2023 models of four popular minivans: the Honda Odyssey, Toyota Sienna, Chrysler Pacifica and Kia Carnival.

The study by the nonprofit organization found that none of the minivans tested received an "acceptable" or "good" safety rating, a red flag for anyone considering driving or purchasing one of the vehicles. The IIHS focused on how back-seat passengers fare in a head-on collision.

While all the minivans performed well in protecting front-seat passengers, the results were significantly less favorable for the test dummy in the back seat that was the size of a 12-year-old.

Jessica Jermakian, vice president of the IIHS, told "CBS Mornings" that in all four minivans tested, the "rear occupant was at an increased risk of chest injury, either because of poor belt positioning or high belt forces."

Three of the four minivans — the Sienna, Pacifica and Carnival — received an overall "marginal" rating. The Honda Odyssey received the lowest rating: "poor." 

The minivans performed well in past crash tests, but the IIHS raised the standards for testing because it believed back-seat passengers were being overlooked. The results across various vehicle classes, from small and midsize SUVs to sedans and small pickups, show a need for improvement in vehicle safety.

"People in the rear seat are at increased risk of fatal injury compared with those in the front seat. And it's not that the rear seat has gotten less safe over time. It's that the front seat has gotten so much safer by comparison," Jermakian said.

Automakers say they are reviewing the findings and that safety is a top priority and their vehicles meet or exceed federal safety standards. 

The Alliance for Automotive Innovation, a trade association, said "safety is a top priority of the auto industry."

"Vehicles on the road continue to get even more safe as automakers across the board test, develop and integrate breakthrough safety technologies that save lives and prevent injuries," it said. 

Stellantis said in a statement: "No single test determines vehicle safety."

"We engineer our vehicles for real-world performance. We routinely consider third-party ratings and factor them into our product-development process, as appropriate. We have a long history in the minivan segment. The security and protection of our customers are critical concerns at Stellantis. Every Stellantis model meets or exceeds all applicable federal vehicle safety standards," it said.

Honda said: "American Honda is a leader in Insurance Institute for Highway Safety (IIHS) safety ratings with ten Honda and Acura models recognized by the institute with their 2023 TOP SAFETY PICK or TOP SAFETY PICK+ ratings, including the 2023 Honda Odyssey. IIHS' updated moderate overlap testing with new rear passenger metrics challenges models fully engineered prior to the introduction of the new test mode, as seen by the results for each of the models included in the most recent minivan evaluations. The all-new 2023 Accord, by comparison, led IIHS' moderate overlap testing of midsize sedans, as the only of seven models tested to score GOOD in all rear passenger injury measures."

Kia also responded, saying: "Kia America places a priority on vehicle safety, and all Kia vehicles sold in the United States meet or exceed federal motor vehicle safety standards. Occupant protection is complex and involves a diverse range of variables, and Kia is proud of its strong safety record and integrity of its products. Kia will carefully evaluate the results of this test by the Insurance Institute for Highway Safety as part of its commitment to continuous improvement in occupant protection."

Toyota did not respond to CBS News' request for comment.

Kris Van Cleave

Kris Van Cleave is CBS News' senior transportation and national correspondent based in Phoenix.

Twitter