Obama's limo will be a Caddy like no other Truck-based limo's windows, body built to repel projectiles

After President Obama takes the oath of office in January, he may have a shiny new black limousine to go along with his not-so-new White House. General Motors is believed to be putting the final touches on a new first car.

An analysis of unauthorized photographs taken while the car was being tested last summer on public roads suggests that the presidential ride will be a truck-based Cadillac. It will presumably replace the Cadillac that President Bush has used since 2005.

This new car will be a Caddy like no other. The photos by Chris Doane, a spy photographer who hunts big automotive game - future models that haven't been publicly revealed - for magazines and Web sites, provide clues about how specialized presidential transportation has become since the first White House fleet was ordered for William Howard Taft in 1909. President Taft rode in a stock White steam car or a conventional Pierce-Arrow, but the next president will travel in a fortresslike vehicle that was mostly built from scratch.

The photographer noted that the limousine was being tested, possibly for comparison purposes, with a pair of GMC Topkick medium-duty trucks. The limousine seemed to be riding on the same 19 1/2-inch Goodyear Regional RHS tires as the trucks, indicating that it is far heavier than a civilian Cadillac - even the longest stretch limousines built with the GM division's heavy-duty coachbuilder package. Indeed, it is believed that the limo is based on GM's 2500 line of trucks, which includes an extra-heavy-duty version of the Suburban.

Although the raised roof and wide windshield pillars are inherited from the ultra-armored limousines that entered presidential service in 2001, only educated guesses can be made about the technical details. Because neither the Secret Service nor General Motors will discuss the car, or even confirm that a new one has been under development, it is impossible to provide basic specifications or dimensions. Calls to Cadillac's media relations department were not returned, and the Secret Service declined to comment.

So people who are curious about such things look for clues and make deductions. I have spent almost 30 years paying close attention to presidential vehicles as part of my interest in what are called professional cars, which also include hearses and ambulances. (I am the author of "Professional Cars: Ambulances, Hearses and Flower Cars," Krause Publications, 2004.)

Other sources I have consulted on cars used by past presidents include "Presidential Cars and Transportation" by William D. Siuru Jr. and Andrea Stewart (Krause Publications, 1995) and "Presidents on Wheels" by Herbert Ridgeway Collins (Bonanza Books, 1971). But my interest has me looking for clues wherever I can find them.

For example, television clips showing Bush entering and exiting the rear doors of his limos indicate that the windows are at least 5 inches thick, almost twice the depth of what was used on presidential limousines in the 1980s and '90s.

While I do not know what type of weapons such thick windows are designed to guard against, a half-inch of transparent armor is enough to stop a .44 Magnum round at point-blank range; at a thickness of 1 1/4 to 1 1/2 inches, the same material can withstand higher-velocity bullets fired from military assault rifles.

Were an attack to occur, the ballistic forces of bullets fired into the windows would be absorbed within a succession of glass and plastic layers, after which a flexible inner coating known as an anti-spall shield would keep glass from entering the passenger compartment.

Though the materials protecting the car's body are also classified, they are probably intended to break up incoming projectiles with a hard substance before their energy is dissipated by a soft substance. Material traditionally used for this purpose includes dual-hardness steel, aluminum, titanium and ceramics.

Large steel overlaps are also typically added to the body openings of armored autos to deter attackers who might try shooting through the door gaps.

Denied the convertible tops and sunroofs that were once found on presidents' cars, and seated behind glass that is half as transparent and several times as sound-absorbent as that of a standard car, the president has limited interaction with the public while inside his limo. But he can make his presence known by turning on fluorescent interior lighting that makes him visible to bystanders, or by using the built-in public address system.

Aircraft tie-downs welded to the chassis allow the limousine to be transported aboard a military cargo jet, which also often carries the Secret Service's Suburban escort vehicles and at least one limo used as a backup or decoy.

On television footage of a trip to Pakistan in March 2000, it appeared as though President Bill Clinton's motorcade used five decoy cars.

Thus, it is likely that GM is building not just one new presidential limousine, but perhaps two or three that can be used as backups or decoys. There will be no way of knowing until the cars are seen together.

Presidential limos would have great appeal to collectors. But the Secret Service has shown no enthusiasm for letting recent White House cars fall into private hands. When the cars are retired, they often disappear, to be destroyed or used in Secret Service training.

The Department of State also uses specialized vehicles, and the agency's disposal methods have been detailed in a document entitled "Bureau of Diplomatic Security's February 2004 Armored Vehicle Program." Methods include burial at sea, explosive demolition, burning, crushing or burial on land controlled by the federal government.

In the same spirit, the Clinton Presidential Library in Little Rock, Ark., was not given the keys to the 42nd president's 1993 Cadillac Fleetwood, which is displayed there.

"We can dust the outside of the car, but if we needed to get inside it, we would have to contact the regional Secret Service office," Christine Mouw, the library curator, said in an interview. "We've had requests from people to exhibit it with the doors open, but we're told we can't do it for security reasons, which is logical."