NEW YORK (CNN/Money) - Front crash tests on five small cars by the Insurance Institute for Highway Safety yielded the first "Poor" rating given by the Institute since 2001.

2005 Kia Spectra

"The Kia Spectra's poor performance was a surprise, said Adrian Lund, the Institute's Chief Operating Officer. "Most manufacturers have figured out how to design vehicles to do a good job of protecting people in frontal crashes. Kia lags behind its competitors."

In the Kia Spectra, a Korean-made small sedan, a crash dummy's head "bottomed out" an air bag and struck a door frame. High impact forces were recorded on the dummy's head and the test showed the possibility of injuries to an occupant's neck, chest and both legs.

"We were surprised at the outcome," said Kim Custer, a spokesman for Kia Motors America. "We expected a much higher rating than we got"

Data from the test have been sent to Kia engineers in Korea so the company can find ways to improve on those results, Custer said.

"We'll be keeping in touch with the Insurance Institute as we try to impliment changes in the future," he said.

Among the small cars tested, the Mazda3 performed best. Measures taken from the head, neck, chest and legs indicated a low risk of injury even in the fairly severe crash mimicked by the Institute's test.

2005 Mazda3

The front crash test performed by the institute involves pulling the car at 40 miles per hour into a deformable barrier, which the vehicle strikes with just the driver's side of the front bumper. This concentrates crash forces in a relatively small area and causes the crash dummy's upper body to move diagonally rather than straight ahead.

The Hyundai Elantra, a vehicle which shares chassis and drivetrain engineering with the Kia Spectra, ultimately received the Institute's highest rating of "Good" after being tested three separate times.

New small car crash test results Institute for Highway Safetay front crash ratings for five newly tested small cars. Make and model  Rating  Mazda3  Good (Best pick)  Hyundai Elantra  Good  Suzuki Forenza  Acceptable  Saturn Ion  Acceptable  Kia Spectra  Poor   Source:

When the Institute tested a 2001 Elantra an airbag took too long to inflate, resulting in impact forces to the crash dummy's head.

Hyundai then redesigned the front airbag for the 2004 model year. When that version was tested, the crash dummy fared well, but the gasoline tank, filled with an inert fluid for the test, leaked after the impact.

After identifying an improperly placed fuel hose clamp, Hyundai repositioned the clamp and, in April and July 2004 recalled Elantras to fix the problem on cars already on the road. Hyundai again requested that the Institute retest the cars with the repositioned clamp.

In the third test, no fluid leaked from the gasoline tank, but the driver's side airbag failed to deploy. Hyundai engineers will modify software that controls airbag deployment, the Institute said, and agreed to recall cars already manufactured. Hyundai announced those recalls earlier today. Click here for more.

In a third test, with improved airbag software, the Elantra's gas tank did not leak and the airbag inflated properly.

"The structure was good and injury measures for the neck and chest were low," said Lund. "But there was the possibility of a head injury and a right leg injury, so the Elantra isn't good enough to be a 'best pick.'"

The Suzuki Forenza and the Saturn Ion both received an overall rating of "Acceptable," the second-best of four possible ratings.

Julie Vallese of CNN NewsSource contributed to this report.