General Motors' Buick brand is reinvigorating its car range with a new premium saloon, the 2005 LaCrosse, and axing the ageing Century and Regal.

According to Associated Press (AP), the LaCrosse, debuting on Wednesday at the Chicago motor show, will be on sale this autumn.

The new model is said to highlight a renewed emphasis on cars at Buick, the 100-year-old brand that made its name producing reliable passenger cars, particularly for older buyers.

AP noted that much of Buick's focus in the past few years has been on truck-based vehicles like the Rainier and Rendezvous sport utility vehicles and Terraza crossover sports van coming later this year. The 2002 Rendezvous was Buick's first truck in 80 years.

"LaCrosse is a very important model for Buick," Mark Hines, marketing director for Buick's midsize cars, told Associated Press, adding: "Not only does it set the stage for renewal of our entire car line, but it replaces two models that account for almost half of Buick car sales."

Buick US sales fell 22% in 2003, with a 30% slump in car business.

AP noted that GM officials have said the brand's future range - forecast to be split evenly between cars and truck-based models - could include a new full-size saloon, a rear-wheel-drive flagship saloon and a convertible.

Built at GM's assembly plant in Ontario, Canada, the LaCrosse, will offer two engine choices. One is the 3.6-litre V6 from a new GM engine family now being built in several global locations including the US and Australia. Under the bonnet of the new Buick it delivers an estimated 240 horsepower and estimated fuel economy of 19 miles per gallon in the city and 28 mpg on the highway. The other engine is a 200-horsepower version of GM's time-served 3.8-litre V6 already used in the flagship Park Avenue and full-size LeSabre. Estimated fuel economy is 20 mpg in the city and 29 mpg on the highway.

According to Associated Press, though the LaCrosse replaces the Regal and Century, there will be a short-run 2005 Century model, to be built between March and October of this year.

The model names have a heritage. According to AP, Buick used the Century name in model years 1936-42, 1954-58 and 1973-2005 while Regal was used in the 1973-2004 model years.

Power Information Network reckons Buick attracts the oldest US buyer of all automotive brands - its owner base is 64 years old on average, compared with 61 for Mercury and 55 for both Cadillac and Lincoln, AP noted.