WASHINGTON Micro cars can give motorists top-notch fuel efficiency at a competitive price, but the insurance industry says they don't fare too well in collisions with larger vehicles.

In crash tests released today, the Insurance Institute for Highway Safety found that drivers of 2009 versions of the Smart "fortwo," Honda Fit and Toyota Yaris could face significant leg and head injuries in severe front-end crashes with larger, midsize vehicles.

"There are good reasons people buy mini cars. They're more affordable, and they use less gas. But the safety trade-offs are clear from our new tests," said Adrian Lund, the institute's president.

Automakers who manufacture the small cars said the tests simulated a high-speed crash that rarely happens on the road. They also said the tests rehashed past insurance industry arguments against tougher fuel efficiency requirements. The institute has raised questions about whether stricter gas mileage rules, which are being developed by the government, might lead to smaller, lighter vehicles that could be less safe.

"If you were to take that argument to the nth degree, we should all be driving 18-wheelers. And the trend in society today is just the opposite," said Dave Schembri, president of Smart USA.

Sales of small cars soared when gas prices topped $4 per gallon last year but have fallen off as gasoline has retreated to about $2 a gallon and the economic downturn has slowed car sales. The small cars are affordable prices of the three cars tested range from about $12,000 to $18,000 and typically achieve 30 miles per gallon or more.

The tests involved head-on crashes between the fortwo and a 2009 Mercedes C Class, the Fit and a 2009 Honda Accord and the Yaris and the 2009 Toyota Camry. The tests were conducted at 40 miles per hour, representing a severe crash.

In the fortwo collision, the institute said the Smart, which weighs 1,808 lbs, went airborne and turned around 450 degrees after striking the C Class, which weighs nearly twice as much. There was extensive damage to the fortwo's interior and the Smart driver could have faced extensive injuries to the head and legs. There was little damage to the front seat area of the C Class.

Schembri said the test simulated a "rare and extreme scenario" and noted that the fortwo had received solid ratings from the government's crash test program. The fortwo has received top scores from the Insurance Institute in front-end and side crash tests against comparably sized vehicles but in the front-end tests against the C Class, the institute gave the mini car poor marks.

In the Fit's test, the dummy's head struck the steering wheel through the air bag and showed a high risk of leg injuries. In the vehicle-to-vehicle test, the Fit was rated poor while the Accord's structure held up well.

Honda spokesman Todd Mittleman said the tests involved "unusual and extreme conditions" and noted that all 2009 Honda vehicles had received top scores from the Insurance Institute.