"This is an important aspect of occupant protection that needs more attention," said Becky Mueller, a research engineer at the institute. In 2014, more than 1,600 people who were passengers in the front seat of vehicles were killed in accidents. That was just over 13 percent of all in-vehicle fatalities from that year.
Mueller said the difference in protection between drivers and passengers was due in part to some automakers placing a greater emphasis on the vehicle frame and structure for the driver's side of the SUV. That's because front overlap crash tests were introduced in 2012 and focused on what happened when the driver's side corner of the vehicle hit another car or pole.
Still, even in some vehicles with a symmetrical design for the front of the SUV, front overlap crash test results for the driver's side and passenger's side yielded different results.
"Some vehicle structures look the same on both sides, but they don't perform the same," said Mueller.
Toyota, which makes the 2015 RAV4 that received a poor rating, called these new crash tests severe and beyond federal safety standards.
"Looking ahead, we've incorporated enhancements on both the driver's and passenger's side for vehicles built on Toyota's new TNGA platforms, beginning with the 2016 Prius," said Steve Curtis, a Toyota spokesperson.
Spokespersons for Nissan and Subaru, which had small SUVs that earned "marginal" ratings, told CNBC their companies were committed to meeting safety standards and planned to review the institute's findings.
It's likely this new round of crash tests could force automakers to further modify the frame and structures of the front of their vehicles so they better protected passengers from one of the deadliest collisions.
Questions? Comments? BehindTheWheel@cnbc.com.
Correction: This story was revised to correct the spelling of Becky Mueller's first name.