The U.S. Insurance Institute for Highway Safety slapped each of the four minivans in the U.S. and Canadian markets with less than acceptable ratings in its new moderate front overlap crash test, which places a higher emphasis on back seat safety.
The Chrysler Pacifica, Kia Carnival and Toyota Sienna received IIHS' "marginal" rating; the Honda Odyssey was rated "poor."
The unfavourable ratings stem from adopting improved airbags and advanced seat belts in front seats while overlooking the second row, creating a "safety gap," Joe Young, a spokesperson for IIHS, told sibling publication Automotive News.
IIHS found that newer, advanced airbags and restraints are "rarely available" in the back.
"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 in a statement.
While safety has improved in the front seats, there has been a comparative increase in the risk of fatal injury for belted, second-row passengers, according to research conducted by IIHS.
IIHS updated its test last year after it discovered the finding. The new test represents the first time the agency has used a dummy in the back seat to test frontal crash safety.
Automakers have done a good job with improved frontal airbags and more sophisticated restraint systems in the front but may not have been doing internal testing to find opportunities to enhance second-row safety, Young said.
IIHS is confident automakers will take note and make the changes quickly, he said, as most updates will not require structural alterations to the vehicle.
The Carnival and Odyssey are expected to undergo a freshening in 2024, which would provide opportunity for the automakers to enhance safety in the second row. That's also the case for the Sienna, which is slated for a freshening in 2025. The Pacifica is unlikely to receive incremental changes as an all-electric version of the minivan in 2028 is likely.
Even with the new developments, IIHS said the back seat is still the safest place for children, who can be injured when front airbags inflate. Additionally, the rating does not apply to children secured properly in car seats.