Five large family passenger cars and three large luxury models earned top ratings yesterday in frontal crash tests by the insurance industry.

The highest ratings went to five 2005 family vehicles -- the Buick LaCrosse, Chrysler 300, Ford Five Hundred, Kia Amanti and Toyota Avalon -- and three luxury passenger cars -- Acura RL, Cadillac STS and Lexus GS.

In the front crash test, vehicles strike a barrier on the driver's side at 40 mph.

Adrian Lund, the chief operating officer at the Insurance Institute for Highway Safety, an industry-funded group, said Chrysler had made strides in the frontal protection offered by the 300, which sells for at least $24,200.

In 1999, two of the 300's predecessors, the Chrysler LHS, and its corporate twin 300M, received the institute's lowest rating for frontal crashes. In the recent tests, however, the 300's front compartment maintained its shape, letting the air bag and seat belt protect a crash-test dummy. When the dummy moved forward into the air bag, it returned to the seat without its head striking any structure that could have caused injury.

Lund called the 300 a "good performer across the board in the frontal test. This is the kind of performance we like to see."

The institute commended Ford Motor Co. for the steady performance of the Five Hundred, noting that previous Ford family sedans, the Taurus models of 1995, 1996 and 2000, received top ratings in frontal tests. The starting retail price of the Five Hundred is $22,840.

The 2005 Acura RL, with a starting retail price of $49,100, was also considered an improvement, with previous versions rated acceptable because the dummy's head struck the pillar between the front and rear doors in testing.

The 2005 RL had an improved structure that reduced the likelihood of injuries in a similar crash, Lund said.

It also found improvement in Cadillac's crashworthiness for the STS, which has a starting price of $41,220. The STS's immediate predecessor, the 2000 Seville, earned a good rating in the frontal test, but the 1997 Seville was rated poor because its structure crumpled during the crash test and the instrument panel pushed back toward the driver.