The 2004 Toyota RAV-4 got the highest ratings on both front and side crash tests performed by the insurance industry, but only when tested with its optional side air bags, according to crash test results released yesterday.

The Insurance Institute for Highway Safety said the RAV-4 was the first vehicle to earn its "best pick" designation for both front and side tests. The institute began performing side-impact crash tests last year. When tested without its side-impact air bags, however, the RAV-4 received the institute's lowest rating of poor in the side test.

Adrian Lund, chief operating officer of the Insurance Institute, said he hoped the results would encourage Toyota and other manufacturers to make head-protecting side air bags standard.

Toyota spokeswoman Martha Voss said she did not know whether the company would make air bags standard on the RAV-4. It now costs $680 for the option, which includes a head-protecting air bag that deploys from the ceiling and a side-protecting air bag that deploys from the seat.

The Insurance Institute tests the performance of vehicles in a 31-mph side crash. Lund said the 2003 RAV-4, which did not offer optional side air bags, had poor structure and failed to protect the crash dummy's head. Toyota strengthened the structure of the 2004 RAV-4 along with adding the side air bags option.

Lund stressed that head-protecting air bags can reduce by 45 percent chances of serious injury in a crash, while side air bags, designed to protect the chest and abdomen, reduce chances of injury by only 10 percent.

Toyota also made structural improvements to the front of the RAV-4 which helped the vehicle withstand the institute's 40-mph frontal crash test, Lund said.

The 2004 RAV-4 got the highest side-impact safety rating from the government even though it was tested without its air bags. Institute spokesman Russ Rader said the National Highway Traffic Safety Administration uses a barrier that represents a car, while the institute's barrier represents a sport utility vehicle. He said the NHTSA also doesn't include the amount of head injury in its calculations.

The institute also released results for the 2005 Subaru Legacy sedan, which earned a "best pick" in the frontal crash test but the second-lowest rating on the side-impact test even though it has standard side air bags. The institute said the air bag, which deploys from the ceiling, protected the head but not the lower body.

The insurance institute tested both vehicles because they have been recently redesigned. The institute buys all the vehicles it tests off dealer lots.