Honda's 2005 Acura RL sedan won the top U.S. auto grade of five stars on all crash and rollover tests, the third vehicle to earn the highest ratings in tests by U.S. auto safety regulators.

Ford's new Five Hundred sedan and the similar Mercury Montego received five stars on each of four crash tests performed by the National Highway Traffic Safety Administration.

Ford's Volvo S80 and Lincoln Town Car/Ford Crown Victoria from 2003 through 2005 also received five top grades.

The agency tests new models, such as the Five Hundred, and redesigned vehicles.

Crashing a car into a fixed object gauges effects on drivers and passengers. A side crash test, using a sled that strikes a vehicle, assesses injuries to passengers in the front and rear seats. A rollover rank is calculated using test track performance and a formula based on vehicle width and height.

The agency did 13 crash tests and issued 29 rollover ratings. General Motors's new Pontiac G6 won five stars in the front test for driver and side crash for rear passengers, four stars for front passenger and three stars for the driver side test. Toyota's new Scion tC had a single five-star grade and three with four stars.

The only other five-star grades in the rollover rankings went to Ford's redesigned Mustang and DaimlerChrysler's new Crossfire coupe.

None of the vehicles in any test received less than three stars, the average grade on a scale of one to five stars.

The Five Hundred's grade on the rollover test was four stars, the same as 20 other models in that test.