In a test that duplicates what happens when the front corner of a vehicle strikes another car or object, only one of 11 minicars evaluated earned an acceptable rating.
That makes these tiny cars the worst performing group of any evaluated so far by the Insurance Institute for Highway Safety.
The Chevrolet Spark's acceptable rating, as well as good ratings in the institute's four other crash tests, qualifies the minicar for the 2014 "Top Safety Pick" award. No other minicar model is a winner yet this year.
Introduced in 2012, the small overlap front crash test shows what happens when 25 percent of a vehicle's front end on the driver's side strikes a barrier at 40 mph. The test is harder to pass than the head-on crashes conducted by the government or the institute's moderate overlap test, in which 40 percent of the front end strikes a barrier. When only a corner of the car hits an object, the impact often bypasses the vehicle's main structural elements designed to absorb the crash energy. As a result, the driver and passenger compartment can collapse.
Still, manufacturers of other vehicles have found ways to improve vehicle structures to meet the challenge.
"Small, lightweight vehicles have an inherent safety disadvantage. That's why it's even more important to choose one with the best occupant protection," Joe Nolan, IIHS senior vice president for vehicle research, said in a press statement. "Unfortunately, as a group, minicars aren't performing as well as other vehicle categories in the small overlap crash."
Small cars have done much better as a group than minicars. Among 17 small cars tested so far, five earned good ratings and five earned acceptable ratings in the institute's small overlap test.
Among the minicars tested, the two worst performers were the Honda Fit and the Fiat 500. In both cases, the crash pushed the steering column back toward the driver.
The institute said that consumers should remember that although the Spark offers more protection than other minicars, it still weighs less than 2,500 pounds and doesn't protect as well as a larger and heavier vehicle with a comparable rating. Frontal crash test results can't be compared across weight classes.
Full test results are available on the IIHS website.