They're small, cute, easy to park, and gentle on your wallet at the gas station. But you don't want to get rear-ended in one.

That's the verdict on mini-cars such as the Mini Cooper, Toyota Yaris and Chevrolet Aveo, as delivered this week by the Insurance Institute for Highway Safety, a nonprofit adjunct of the auto-insurance industry whose members' wallets depend in part on your continued well-being.

None of the seven 2007 mini-cars scored better than "marginal" in a test that simulates the effects of one of the most common accidents: a car stopped at a traffic light being rear-ended by a similar car traveling 20 m.p.h.

Three models - the Aveo, Honda Fit and Hyundai Accent - scored "poor" in that test, a result that Stephen Oesch, senior vice president of the institute, said represented "a good possibility of a very serious neck injury."

The Accent, also sold as the Kia Rio, was the worst overall performer. It also was rated "poor" in the study's side-impact test, which mimics what happens when a car is broadsided by an SUV or pickup truck traveling 31 m.p.h., and won an "acceptable" in the institute's front-impact test - a test on which most of the other cars scored a "good," the top score in a four-step rating system. On the side and front tests, a "poor" means a serious or fatal injury is likely in a crash.

The insurance institute began crash-testing in 1995, starting with the front-impact test, and its influence on safety is evident in the mini-car results. Oesch said drivers of five of the seven cars would likely avoid any serious injury in the kind of crash the frontal test simulates, in which two cars traveling at 40 m.p.h. in opposite directions collide not quite head-on.

The institute added the side-impact test in 2002 after alarm was raised about the physical mismatch when a high-riding SUV or pickup broadsides a passenger car. Two years later, it added the rear-impact test to address concerns about frequent whiplash injuries, which typically occur when a victim's neck is thrown backward and then forward in a rear-end crash.

None of the seven mini-cars were rated "good" in all three tests. But the institute did give three top marks to an eighth model it included in the test group, the Nissan Versa. Although slightly larger and heavier than the mini-cars, the Versa was included because "it's marketed in the same way," Oesch said. (To see full test results and a video of some of the crashes, go to http://www.iihs.org/news/default.html.)

The insurance institute is widely credited with pushing manufacturers to design safer vehicles, and also with prompting the federal government to update vehicle-safety standards. (For information and federal crash-test results, go to www.safercar.gov.)

But progress in that arena has been slow - one reason for the wide variation in cars' crash performance.

For example, federal standards for head restraints, a key protector against neck injuries, went unchanged from 1969, when they were first set, until 2005. But the new standards will not go into effect until the 2009 model year, Oesch said.

Clarence Ditlow, executive director of the nonprofit Center for Auto Safety, also praises the institute for focusing on injuries even though vehicle repairs represent a larger portion of insurance claims.

Still, big money is at stake. Oesch said neck injuries resulted in two million claims a year that cost auto insurers about $8 billion - about one-quarter of all injury claims.

"One in 10 of those crashes results in long-term pain or disability," Oesch said. "It's an issue we're really trying to address."

Side air bags are also a major factor in better crash safety - illustrated by the institute's contrasting tests of two Toyota Yarises, one equipped with the air bags, the other without.

In the Yaris with the optional side air bags, the crash dummy escaped largely unscathed in the side-impact test, thanks to the bags and to the Yaris' stiff body structure, Oesch said.

Without the air bags, the impact by the 31-m.p.h. SUV simulator was enough to cause the Yaris driver serious injury or death.

Review safety reports and access video of crash tests for these automobiles via http://go.philly.com/minicrash

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By Jeff Gelles
Inquirer Staff Writer

Contact staff writer Jeff Gelles at 215-854-2776 or jgelles@phillynews.com.

© 2006 Philadelphia Inquirer and wire service sources. All Rights Reserved.