The Insurance Institute for Highway Safety (better known as the people that get paid to smash cars into walls) recently put 11 mini cars — including well-known models like the Fiat 500, Honda Fit, Hyundai Accent, and Toyota Prius C — through its newest form of crash-testing. The results were not good, with only one of the tested vehicles earning an overall “Acceptable” rating.

The IIHS small overlap test looks at what happens when only the front corner of a vehicle is involved in a crash. This is one of the more common results of a vehicular accident — veering off the road into a tree, clipping the corner of a another car in traffic, hitting the side of a building or railing — but many car makers have not designed their vehicles to protect the driver in these cases.

The testers determine the crashworthiness in this particular test by crashing 25% of a vehicle’s front end into a rigid barrier at 40 mph.

During the first round of small overlap testing in 2012, only three of 11 luxury cars received passing marks from the IIHS. But the results of the mini car tests set a new low for small overlap testing.

“Small, lightweight vehicles have an inherent safety disadvantage. That’s why it’s even more important to choose one with the best occupant protection,” says Joe Nolan, IIHS senior vice president for vehicle research. “Unfortunately, as a group, mini cars aren’t performing as well as other vehicle categories in the small overlap crash.”

The only vehicle to earn an acceptable rating in the test was the Chevy Spark. The small overlap test only resulted in marginal damage to the electric vehicle’s structure, and the dummy placed inside the car appears to have made it out of the collision fully intact. The acceptable score on the overlap test, along with “good” ratings on the IIHS’s other crash tests earned the Spark the Institute’s Top Safety Pick honor.

In terms of structural damage to mini cars, not a single tested vehicle scored above a “marginal” rating.

“When a vehicle’s structure doesn’t hold up, injury risk is high,” explains IIHS. “Collapsing structures can knock frontal airbags and seats out of position, exacerbating the problem.”

One of the most common problems with the tested mini cars was the reaction of the vehicles’ restraint systems. Only two cars — the Spark and the Mazda 2 — earned “acceptable” scores in this category — with six of the 11 vehicles scoring “poor” for a variety of reasons. In some cases, the seat belt failed to effectively hold the crash test dummy in place during the collision. In others, the dummy’s head missed or slid off the airbag.

Speaking of airbags, the side curtain airbag could be a life saver in this sorts of accidents, but the IIHS says side curtain airbags in eight of the 11 cars tested failed to provide adequate coverage. In the Toyota Yaris, the side curtain airbag failed to deploy at all.

Other issues found during the side overlap test was the steering column moving sideways as a result of the collision and the car seats tipping forward.

Almost all of the dummies involved in mini car small overlap tests experienced some level of injury. Only the Spark dummy came out unscathed, in spite of some structural intrusion into the driver’s space. In all other cases, the dummies’ lower legs took the most damage, with seven of the 11 dummies receiving poor scores for protecting drivers below the knees. The dummies in the Hyundai Accent, Fiat 500, and Honda Fit also showed damage to the upper legs and hips.

This is probably why the Fit and the 500 received the two lowest ratings from IIHS.

“In both cases, intruding structure seriously compromised the driver’s space, and the steering column was pushed back toward the driver,” writes the IIHS. “In the case of the Fit, the dummy’s head barely contacted the frontal airbag before sliding off and hitting the instrument panel. During the test of the 500, the driver door opened after the hinges tore. An open door creates a risk that the driver could be partially or completely ejected.”

One might expect mini cars to have similar results to those vehicles in the small car category, but the slight size difference between the two classes appears to make a significant difference in terms of safety. Of the 17 small cars that have been through small overlap testing, five have received “good” ratings, while another five earned an “acceptable” score.

This page contains the full results for the entire mini car class. Click on any individual test result for more details.

Below is a summary of the results from the small overlap test:

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