Two key Toyota models, the flagship Camry sedan and the Prius V wagon, failed a new crash test conducted by the Insurance Institute for Highway Safety, an insurance industry group.
Honda's newly redesigned Accord tied for the top safety rating with the Suzuki Kizashi, a car that will soon no longer be sold in the United States. The redesigned Ford Fusion also scored well.
The results raise concerns that the Toyota models can't provide protection from serious injuries in common accidents. The automaker's new Prius V, a wagon version of the popular hybrid, scored last among 18 cars tested, with "poor" ratings in five of seven categories. The Camry -- America's bestselling passenger car -- scored next to last.
"Toyota engineers have a lot of work to do to match the performance of their competitors," said Adrian Lund, the insurance group's president.
Toyota, in a statement, vowed to focus on improving safety.
"With this new test, the institute has raised the bar again, and we will respond to the challenge," the automaker said.
Toyota said the Camry and Prius V have performed well on other tests and are still rated as "Top Safety Picks" by the organization.
The new test -- in which 25 percent of a car's front end on the driver's side strikes a 5-foot-tall rigid barrier at 40 mph -- simulates a wreck in which the front corner of the car hits another car or a solid object. This was the first test of family cars and follows a similar test this year in which only three of 11 luxury cars scored well.
The front corner crashes can be particularly severe. "The crash damage in these tests is like the damage we see in real-world crashes where heads and chests are injured," Lund said.
The trade group said some automakers, including Honda, Ford and Nissan, are starting to redesign vehicles to protect passengers in front-corner impacts, and that's one of the reasons the family cars fared better than luxury cars.