Has Hummer had its day? Sales of the all-American company’s models have slumped by nearly one-third, as US buyers lose their appetites for super sized cars. And bosses at owner GM have now officially confirmed Hummer’s future hangs in the balance.

In a statement, GM said it was “considering anything from a complete revamp of the product line-up to a sale of the brand”.

Hummer sales in the States dropped by 29 per cent by the end of April, compared to the same period last year. Ironically, it is doing quite well in the UK and Europe, with around 300 cars finding homes – a rise of 34 per cent. But it’s not only the Hummer that’s out of favour in America. There has been a dip in demand for larger cars across the board, prompting GM to announce the closure of four plants that build pick-ups, SUVs and trucks.

The shift has even seen the Ford F-150 pick-up lose its top spot in the US charts. It’s been the best seller every month since 1981, but was overtaken in May by the Honda Civic.

Popularity: 3% [?]

Arnold Schwarzenegger and David Beckham are the emblems of the end of an American economic era. Each owns at least one Hummer, the giant SUV designed around the army’s Humvee personal troop transporter.

But the Hummer has fallen out of favour and was last week put on the block by General Motors. It is little wonder. Who would want to buy a beast that does nine miles to the gallon and costs more than $100 - £50 at the pump is a small fortune to Americans - to fill up?

GM also closed four SUV assembly plants as it put Hummer up for sale. But these drastic moves by GM are more significant than they at first seem.

The desire to own big, thirsty motor vehicles with V6 and V8 engines, capable of transporting families over vast tracts of asphalt-covered prairie and mountain range, was a defining tenet of the American economic model of the past century.

Building roads and making cars to drive on them was a central plank of the New Deal, the economic plan devised by President Roosevelt to drag the country out of the Great Depression.

A network of state parkways was conceived and built in the 1930s and 1940s by Robert Moses, the father of American urbanism. His blueprint for a society dominated by the car spread until, by the 1960s, the entire nation was covered by a web of interstate highways. This was the American Dream.

But today, with oil above $130 a barrel and stories on the news every night about commuters who cannot afford to commute and hauliers who cannot afford to haul, the dream is over. David Cole, director of the Centre for Automotive Research in Detroit, believes that America is on the threshold of a new technological era and in the next five to 10 years advances in bio-fuels - using material such as algae, sewage and waste - will enable Americans to drive big cars at a fraction of the environmental and economic cost.

GM has invested heavily in two companies who claim that their bio-engineering and genetic modification methods can produce alternatives to petrol costing about $1 a gallon. But a bold government move may also be required. Cole, who fears that the oil price will take a tumble, is calling it to set a $50 floor for the price of a barrel of crude. If oil becomes too cheap, he believes, the impetus to invest in new technology will be lost.

It may be that Arnie and Becks will be able to keep driving their dinosaurs, but with bio-fuel in the tank instead of petrol.

Popularity: 2% [?]

The 2009 Dodge Ram could boast a 20 percent improvement in fuel efficiency, executives said Thursday morning.

The new Ram, which will roll into dealers this fall, includes an improved 5.7-liter Hemi V-8 that has become more powerful and more efficient, said Mike Cairns, the Ram’s chief engineer.

The new engine, which produces 380 horsepower and 404-pound-feet of torque, has become about 5 percent more efficient, he said. The additional mileage gains were credited to significant work to make the Ram more aerodynamically efficient and by cutting 80 pounds from the truck’s overall weight.

“We expect to see a 10 to 20 percent gain in highway efficiency,” Cairns said.

The 2008 Ram Quad Cab Laramie with a 5.7-liter Hemi gets 15 mpg in the city and 19 mpg on the highway. Raising the highway mileage to 23 mpg on the highway makes it one of the most efficient full-size pickups on the road. Four-by-four models using the 5.7 Hemi typically hit about 17 mpg on the highway.

“This is the best truck Dodge has ever made,” said Dodge’s director Mike Accavitti.

Dodge, the No. 3 pickup manufacturer in the United States, sold 358,000 trucks last year. However, high gas prices and changing consumer demands have caused Ram truck sales to drop 24 percent this year through April, according to Autodata Corp.

The new Ram touts 35 significant changes inside and out over the 2008 model.

Popularity: 7% [?]

HUMMER H3 SUV

Popularity: 1% [?]

Chevrolet Silverado 1500

Popularity: 1% [?]

Chevrolet Silverado 2500HD

Popularity: 1% [?]

Chevrolet Suburban 2500

Popularity: 1% [?]