Minivans are often popular for parents with young children, and ought to boast the safest second-row seating on the market. Instead, they’re lagging behind.

None of the four 2023 minivans tested by the Insurance Institute for Highway Safety (IIHS) earns an acceptable or good rating in the updated moderate overlap front crash test, which now emphasizes back seat safety. The Chrysler Pacifica, Kia Carnival, and Toyota Sienna are rated marginal, while the Honda Odyssey is rated poor. All but the Sienna also lack seat belt reminders for the second-row seats.

“Back seat safety is important for all vehicles, but it’s especially vital for those, like minivans, that customers are choosing specifically to transport their families,” IIHS President David Harkey said. “It’s disappointing that automakers haven’t acted faster to apply the best available technology to the second row in this vehicle class.”

In the updated test, a second dummy is positioned in the second row behind the driver. The driver dummy is the size of an average adult man. The rear dummy is the size of a small woman or 12-year-old child. IIHS researchers also developed new metrics that focus on the injuries most frequently seen in back seat passengers.

For a vehicle to earn a good rating, there can’t be an excessive risk of injury to the head, neck, chest or thigh, as recorded by the second-row dummy. The dummy should remain correctly positioned during the crash without “submarining,” or sliding forward beneath the lap belt, which increases the risk of abdominal injuries. The head should also remain a safe distance from the back of the front seatback and the rest of the vehicle interior, and the shoulder belt should remain on the shoulder, where it is most effective. A pressure sensor on the rear dummy’s torso is used to check the shoulder belt position during the crash.

All four minivans provide good protection in the front seat. But each is plagued by multiple issues when it comes to the second row.

“The restraint systems in all four vehicles leave the second-row occupant vulnerable to chest injuries, either because of excessive belt forces or poor belt positioning,” said Jessica Jermakian, IIHS vice president of vehicle research. “That’s concerning because those injuries can be life-threatening.”

IIHS launched the updated moderate overlap front test last year after research showed that the risk of a fatal injury in newer vehicles is now higher for belted occupants in the second row than for those in front. This is not because the second row has become less safe. Rather, the front seat has become safer because of improved airbags and advanced seat belts that are rarely available in back. Even with these developments, the back seat remains the safest place for children, who can be injured by an inflating front airbag, and the rating does not apply to children secured properly in child safety seats.