Question: What car is typically used to transport the president?

Motorcade


A motorcade, or autocade, is a procession of vehicles.
Etymology
The term motorcade was coined by Lyle Abbot (in 1912 or 1913 when he was automobile editor of the Arizona Republican), and is formed after cavalcade on the false notion that "-cade" was a suffix meaning "procession".  In fact, there is no such suffix in either French or Latin, although -cade has now since become a productive suffix in English, leading to the alternative names carcade, autocade, and even Hoovercade (after J. Edgar Hoover). Eric Partridge called the name a "monstrosity", and Lancelot Hogben considered the word to be a "counterfeit coinage".  The original suffix in cavalcade is actually "-ade".[1][2][3]
Uses of motorcades
Funerals

A funeral cortege is a procession of mourners, most often in a motorcade of vehicles following a hearse.[4]
Protests and demonstrations
Motorcades can be used as protests and demonstrations.[5] A large, organised, group of vehicles will travel a busy route at very slow speed in order to deliberately cause traffic disruption. This is a tactic most often associated with protest groups that have access to many large vehicles, such as truckers and farmers. An example is the 2005 UK protests against fuel prices.[6] As part of the Euromaidan protests in Ukraine in November 2013—February 2014, the sub-movement that made use of car processions as the means of protest was called the Automaidan.
VIPs

Motorcades can be used to transport a very important person, usually a political figure. Such a procession consists of several vehicles, usually accompanied by law enforcement support and additional protection to ensure the safety of the people in the motorcade. Motorcades for heads of government and heads of state can consist of dozens of vehicles, those being armoured cars, SUVs, and police motorcycles and cars leading the way and following.
Traffic diversions
Depending on the size of the motorcade and who it is carrying, routes may be completely blockaded from the general public. For security, this often occurs for motorcades for heads of state or government.
President of the United States

The motorcade for the President of the United States comprises forty to fifty vehicles; in addition to the president, the motorcade may carry his or her spouse, members of the press, security,  White House officials, and VIP guests. The major members travel in armored vehicles, typically specially configured limousines. The motorcade contains several armored vehicles, a USSS Electronic Countermeasures Suburban, a counter-assault team, and Secret Service agents. When called for, a hazardous materials team precedes the motorcade on alert for potential hazards.
A police presence precedes the beginning of the presidential motorcade. These cars and motorcycles usually drive ahead to clear the way and block traffic.[7]
The motorcade for the president is made up of two parts, the first being the "secure package".[8] In the event of an emergency, the secure package separates from the rest of the group.[8] It includes two limousines heavily guarded by local law enforcement and Secret Service, with all cars driven by professional drivers.[8]
The second part is made up of vans that transport White House staff members and selected members of the press. In the rear is the WHCA Roadrunner communications van – which provides the primary communications path via satellite, allowing bi-directional voice, data and streaming video – an ambulance, and additional police vehicles.[8]
Motorcade routes are selected by Secret Service agents in cooperation with local police forces. Escape routes are also established in the event of an emergency.[8]
Gallery of motorcades

Calvin Coolidge (in top hat) arrives to dedicate a park in Hammond, Indiana, 1927
Franklin D. Roosevelt in New Orleans, 1937
Harry S. Truman leaves Boca Chica Field in Key West, Florida, with Cecil C. Adell (center), and William D. Leahy, retired Chief of Staff to the Commander in Chief, 1951
Dwight D. Eisenhower in Kabul, 1959
John F. Kennedy and Jacqueline Kennedy at Blair House, 1961
Richard Nixon in Berlin, 1969
Following Gerald Ford and Leonid Brezhnev on a tour of Vladivostok, 1974.  Photo by David Hume Kennerly.
Jimmy Carter leaving Three Mile Island, 1979
Motorcade following the inauguration of George W. Bush, 2001
Funeral motorcade for Ronald Reagan in Simi Valley, California, 2004
George W. Bush in Ada, Michigan, 2008
Barack Obama in Baghdad, 2009
Funeral motorcade of Russian patriarch Alexy II in 2008
Motorcade for the Australian Governor General, Prime Minister and Chief of the Defence Force in Canberra, 2009
Motorcade for Queen Elizabeth II, en route to CFB Winnipeg, 2010
Brazilian presidential motorcade at the inauguration of Dilma Rousseff in Brasília, 2011  

See also
Official state car
Air transports of heads of state and government