Half the small cars tested for how they would stand up to a crash did not fare well, an influential road safety group said.
Six of the cars tested, most of which were 2013 models, were rated "poor" or "marginal." The Chevrolet Sonic and Cruze each received marginal scores, while Kia's Soul and 2014 Forte were rated "poor" in the results released on Thursday by the Insurance Institute for Highway Safety.
The Nissan Sentra also was rated "poor," while the Volkswagen Beetle was ranked "marginal."
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The IIHS increased the rigor of its tests last year to include crashes that involve only a front corner of a vehicle. The insurance group said nearly one-fourth of U.S. front-of-vehicle crashes that result in serious injury or death involve only a single corner that strikes another vehicle or an object like a tree or utility pole.
The IIHS continues to score vehicles on side, rear, rollover and front-end crashes that impact more than just a corner.
"This is a challenging new crash test and it's not surprising that some vehicles are earning marginal and poor ratings," IIHS spokesman Russ Radar said of the small overlap front crash test.
"This crash scenario doesn't lend itself to a Band-Aid fix so for most manufacturers the countermeasure will have to be built in when there's a full redesign," he added.
Vehicle manufacturers in the U.S. market often design and engineer their models to score well on IIHS safety tests and use the results in their marketing.
"It matters because in today's world cars are so competitive that all you need is a small flaw and your competition can exploit it," Kelley Blue Book senior analyst Karl Brauer said.
Most of the 12 small cars tested were already in production before the IIHS increased the rigor of its front crash test last year. However, Radar said IIHS alerted the companies to the work the group was doing on small overlap research in 2009.
The specifications of the test were not finalized until the last year, which is late in a car's development process, Brauer said. All automakers will eventually redesign their cars to meet the standards to pass the new crash test, he said.
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In the tests, IIHS crashes a vehicle at 40 mph into a 5-foot-high barrier on the driver's side that overlaps one-quarter of the vehicle's width.
Kia pointed out that the IIHS small overlap crash test goes well beyond federal requirements and the group has recognized numerous Kia vehicles as top safety picks. The South Korean automaker said it would evaluate the results carefully, but the company was proud of its safety record.
GM said customer safety remains its highest priority and it is committed to its cars performing well in all types of crashes.
"We are aggressively working to incorporate these into our models, including our small cars like the Chevrolet Sonic and Cruze, where technically feasible," GM spokeswoman Sharon Basel said in an email.
Nissan and VW said they were proud of their cars' safety records in federal crash tests and other IIHS crash tests, but they would review the small overlap test results and incorporate what is learned into future designs.
In the worst cases with the small cars that did not score well, safety cages collapsed, driver airbags moved sideways and the crash dummy's head hit the instrument panel, and side curtain airbags did not deploy or provide enough protection, IIHS chief research officer David Zuby said.
The small car segment was the fourth group of cars rated using this new test, and most of the groups have fared equally badly.
Last summer, seven of 11 luxury sedans evaluated rated "marginal" or "poor," and 12 of 15 small SUVs tested also failed to score well in results released in May. Family sedans scored the best, with only five of 18 scoring "marginal" or "poor" in results released last December.
As a group, the small cars fared worse than the mid-sized family sedans, but better than the small SUVs, IIHS said. Results on the new crash test for minicars will be released later this year.
The other six small cars tested included two- and four-door versions of the Honda Civic, which both received "good" ratings. The Civic was tested earlier this year and the results were released in March.
Receiving "acceptable" ratings were the Dodge Dart, Ford Focus, Hyundai Elantra and Toyota 2014 Scion.