Eleven minicars were tested by the group, and none of them received the highest rating of "good." The Chevrolet Spark was the only car that earned the second-highest rating of "acceptable" in the small overlap frontal protection test. Six of the cars, including the group's best seller, the Nissan Versa, got the lowest rating of "poor."
All of the cars were from the 2013 or 2014 model years.
The small overlap front crash test is relatively new to the Insurance Institute, but it is one of the most critical in evaluating driver and passenger safety.
The IIHS test mimics what happens when a car's front corner collides with another car or an object like a light pole. In the test, 25 percent of a vehicle's front end on the driver's side strikes a rigid barrier at 40 mph.
This test is different than the U.S. government's frontal crash test, in which a car strikes a rigid barrier head-on at 35 mph.
In several of the subcompact vehicles, the structures collapsed, which can exacerbate injuries because the air bags, seats and other parts get knocked out of position.
"A small overlap crash can be devastating because often the main structural elements of the vehicle are bypassed," said Joe Nolan, IIHS senior vice president for vehicle research. "If the vehicle's not designed for this, that can lead to massive collapse of the occupant compartment and a big reduction in survival space. "
According to the group, the Honda Fit and Fiat 500 were the worst performers in terms of potential injury to drivers.
When put through the crash test, the Fit's steering column pushed so far into the vehicle that the dummy's head slid off the airbag and hit the instrument panel directly. For the Fiat, the force from the crash ripped the door hinges off the vehicle, causing it to fall open.
Both Honda and Fiat pointed out that their cars earned top ratings in the group's other four tests. Honda also pointed out the safety of their customers is of great importance to them and they plan to introduce more safety technologies in the future.
"Honda has an all-new, completely redesigned 2015 Honda Fit that will come to market in just a few months and we anticipate it will earn top safety scores from the Insurance Institute for Highway Safety (IIHS), with a 'good' rating in all test modes including the rigorous small overlap front crash test," Honda said in a statement Wednesday.
Cars with "marginal" ratings were the Kia Rio, Mazda2, Toyota Yaris and Ford Fiesta. Cars with "poor" ratings - in addition to the Fit, the Fiat 500 and the Versa - were the Toyota Prius C, Mitsubishi Mirage and Hyundai Accent.
The Chevrolet Spark's acceptable rating in the small overlap front crash test, along with good ratings in the Institute's four other crashworthiness evaluations, earned the new minicar a 2014 Top Safety Pick award.
