Obama's 'Limo One'

US President Barack Obama - in Australia on November 16 and 17 to celebrate the 60th anniversary of the ANZUS alliance following the APEC leaders' meeting in Hawaii - will be cocooned in "Limo One" as his personal transport. But "Limo One" - or "Cadillac One" or "The Beast" as it has been referred - isn't one car and it isn't even a Cadillac model. In fact it's the only Cadillac that doesn't have a model name though Cadillac refer to it in-house as "Stage Coach".

Built in 2009, it is one of 25 limousines in the Obama Administration. There is believed to be three cars identical in appearance to Limo One and foreign visits by the President may include the transport of up to three of these "clones". The much-publicised grounding of the limousine in May at a bump in the US Embassy driveway in Dublin drew concern about the safety of an immobile  president.

But the car was for secret service personnel while President Obama was in a second, identical car further down the line. Cadillac spokesman David Caldwell says "one of the specifications of the car is that I can't talk about the specifications". He did confirm that there is more than one presidential car and indicated there was a substantial fleet of vehicles within the White House Military Office.

"The Presidential cars serve for a long period of time, in a somewhat overlapping fashion," he says. "Older cars remain in other types of service, for instance. What is learnt about these cars is applied to future cars. "Completely new designs appear periodically ... normally coinciding with inaugural timing." In fact the 2009 Cadillac of President Obama is one of these new designs.

It replaces the 2005 Cadillac DTS-based limousine first used in January 20, 2005 at the second inauguration parade of George W Bush. This car, a stretched DTS sedan built on a GM 4WD chassis, is still regularly in use as an alternate limousine. The latest limousine is believed to also be based on a GM 4WD chassis. The 6m long car is designed to look similar to production Cadillac cars but in detail is a montage of body panels, headlights and tail lights. These components, borrowed from other Cadillac cars, provide the skin over a 6-tonne, grenade-proof armored personnel carrier.

Under the skin is armour plating - of alternating veneers of composite steel, titanium, kevlar and ceramic - up to 150mm thick, with 100mm thick glass windows that - except for the driver's side - are fixed. It is believed to have an arsenal of shot-guns, tear-gas cannons and smoke grenades and has onboard aids such as night-vision cameras, fire-fighting equipment and an oxygen cylinder for the cabin in the event of a chemical attack.

The engine is a supercharged 6.5-litre V8 turbo-diesel which averages 29 litres/100km. Its fuel tank is leakproof and resistant to an explosion, and there are kevlar-lined, run-flat tyres to ensure they won't shred or puncture. The car can seat seven people, including the president. In the US, Limo One - and its entourage of up to 45 vehicles - flies the American and Presidential Standard flags on the bonnet. When in a foreign country, the left-hand side Presidential Standard is replaced by the foreign country's flag. The limousine and its clones are airlifted for domestic and international use primarily by a US Air Force C-17 Globemaster III.

PRESIDENTIAL CADILLACS:

• President Wilson rode in a Cadillac during a parade marking the end of World War I.
• President Coolidge had a 1928 Cadillac Town Car. It featured a 5.6-litre engine with 67kW.
• In 1938, the US government received two Cadillac convertibles - Queen Elizabeth and Queen Mary (after the ocean liners) - each 6.5m long and weighing nearly 4-tonnes. They served presidents Roosevelt, Truman and Eisenhower and were replaced by the Queen Elizabeth II and Queen Mary II, which remained in service until 1968.
• Cadillac returned to the White House in 1983, when President Reagan had a Fleetwood - famous for being the last equipped with the Turbo Hydra-Matic 400 three-speed automatic transmission.
• President Clinton had a Fleetwood Brougham powered by a 7.4-litre V8.