Only one small car out of 12 tested earned a good grade in the latest round of crash-test results compiled by the Insurance Institute for Highway Safety. The Mini Cooper Countryman received a "good" ranking on the organization's small-front overlap test.
Its competitors in the small-car segment didn't do nearly as well. Four vehicles earned "poor" grades, including the all-electric Nissan Leaf and Juke, the Mazda5 and the Fiat 500L, and two more earned marginal scores.
Introduced two years ago, the small front overlap test has been a difficult one for automakers to master, particularly so for small cars, which have less weight to absorb the forces of a car accident. So far, IIHS has tested 32 vehicles in the small-car segment and 13 have earned marginal or poor scores. On the flip side, 19 earned good or acceptable scores.
"Consumers trading the inherent safety of a larger vehicle for the convenience or fuel economy of a small car should focus their search on these vehicles with state-of-the-art safety designs," said Joe Nolan, senior vice president for vehicle research at IIHS.
The small front overlap test simulates what happens when the front corner of a vehicle collides with a stationery object, like a tree or utility pole. They're difficult ones for vehicles to handle, because the crash forces typically bypass safety structures and a car's front-end crush zone. Unfettered, those forces can push into the cabin and injure motorists.
Three green-friendly cars were among those tested in the latest round, making Wednesday's results key ones for consumers mulling a plug-in hybrid or electric vehicle.
Of these three, the Chevrolet Volt did best, earning an "acceptable" score overall and good or acceptable ratings for the way its structure and restraints functioned and protection of the crash-test dummy. An acceptable score on this test allows the Volt to keep its Top Safety Pick+ title from IIHS, the nonprofit safety organization's highest overall honor.
To earn that title, a vehicle must receive a good or acceptable rating on the small-front overlap test and a good rating on four others in the battery of IIHS tests, including moderate-front overlap testing and side impact. The Volt is the only small car in the latest round of tests to earn the Top Safety Pick+ title.
The Ford C-Max Hybrid also earned an acceptable ranking in Wednesday's results, though it received a "marginal" mark for its structure. The all-electric Nissan Leaf was a "poor" performer. In the Leaf, the crash-test dummy was exposed to 16 inches of intrusion in the lower occupant compartment and 14 inches in the upper occupant compartment.
IIHS notes that "the instrument panel, parking brake pedal and steering column were all pushed back toward the driver. Injuries to the left knee and lower left leg would be likely in a crash of this severity, and injuries to the left thigh would be possible."
"Electric vehicles have a unique challenge in the small overlap test because of their heavy batteries," Nolan said.
The Leaf wasn't the only Nissan vehicle to earn a poor grade. Researchers also recorded significant intrusion into the occupant compartment in the Juke, which was the 100th vehicle put through he small-front overlap test back in March. To mark that milestone, IIHS invited Autoblog to its Ruckersville, Virginia headquarters to watch the crash testing.
Although there were no results to share at that time, we noted in our behind-the-scenes look at the Juke test that the dashboard and airbag had shifted several centimeters out of position and that the structure around the lower part of the cabin had buckled. The dummy's feet weren't entirely trapped, but it took several technicians more than an hour to extricate the dummy from the car.
But the real clunker among Wednesday's results was the Madza5. IIHS says it's one of the three worst cars ever tested in the small-car tests, along with the 2014 Kia Forte and the 2012 Prius V.
"When we tested the Mazda5, we saw a host of structural and restraint system problems," Nolan said. "Parts of the occupant compartment essentially buckled, allowing way too much intrusion."
Injury measurements indicate that in a real-world crash, an occupant would have a high risk of injuries to the left thigh and leg. The steering wheel moved so far to the right that the crash-test dummy's head slid off the airbag and impacted the left side of the dashboard.
Worse, the side curtain airbags never deployed, exposing the dummy's head to contact with side structures and outside objects. The driver's door unlatched during the test too. IIHS said "that's something that shouldn't happen, and puts occupants at risk of being ejected from the vehicle."
It's the latest disconcerting crash-test result for the Mazda5. Previously, the car had earned the dubious distinction of being the only 2014 car tested from any segment to earn less than an acceptable rating on the organization's side-impact test.
"Most models earn a good rating," IIHS noted. On that Mazda5 test, measurements taken from the driver showed a likely pelvis fracture, and measurements from rear passengers showed that rib fractures and other internal organ injuries would be possible in a crash of that severity. It earned a "marginal" score.
This article originally appeared on Autoblog.