Economy cars made by Hyundai Motor Co. and Toyota Motor Corp. (TM) received low marks in new side-impact crash tests, the insurance industry said, showing the downsides of driving small.

The Insurance Institute for Highway Safety evaluated several minicars for their ability to protect people in a severe crash. The 2007 Nissan Versa, which offers standard side air bags, received top scores in frontal, side and rear crash protection.

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The 2007 Toyota Yaris with optional side air bags and the 2007 Honda Fit — which has standard side air bags — also got top marks in frontal and side-impact tests.

But four vehicles received the lowest rating of poor in side-impact protection: versions of the 2007 Yaris without side air bags, the 2006 Scion xB, and 2007 models of the Hyundai Accent and the Kia Rio, which share similar underpinnings.

The institute said they tested the economy vehicles for the first time because high gasoline prices have made the small cars more popular. The vehicles, which typically weigh about 2,500 pounds or less, raise some safety concerns because of how they would interact with larger vehicles in a crash.

"People traveling in small, light cars are at a disadvantage, especially when they collide with bigger, heavier vehicles. The laws of physics dictate this," said institute president Adrian Lund.

During testing of the Scion xB, part of Toyota's youth-oriented brand, the institute said the test barrier struck the driver dummy's head, which would have likely caused brain and neck injuries. Side air bags are unavailable on the xB and are a $650 option on the Yaris.

Bill Kwong, a Toyota spokesman, said "we feel our vehicles perform really well in the real-world situation."

The institute also cited the Accent, which has standard curtain-style air bags in the front and rear seats. While the air bags "provided good head protection," they said the driver dummy withstood impacts that would have led to internal organ injuries, broken ribs and a fractured pelvis.

Miles Johnson, a Hyundai spokesman, noted the vehicle has performed well in the government's tests.

The institute said it conducted two frontal tests for the Fit. The air bag deployed too early in the first test, allowing high forces on the dummy's head. Honda spokesman Sage Marie said they would contact customers about a voluntary safety campaign in early 2007 to modify the air bag's software. In a second test, the Fit's air bag deployed properly after Honda made the changes.

Among other vehicles, the 2007 Chevrolet Aveo with standard side air bags received the second-highest score of acceptable for frontal crash protection and the second-lowest mark of marginal for side-impact evaluation.

GM spokesman Alan Adler said the Aveo "meets or exceeds safety standards in more than 120 countries in which it is sold."

The 2006 Mini Cooper was rated good on frontal evaluation and acceptable on the side. The newly redesigned 2007 version is expected in showrooms in the end of February, BMW of North America spokesman Thomas Plucinsky said.

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