A car bomb, bus bomb, van bomb, lorry bomb, or truck bomb, also known as a vehicle-borne improvised explosive device (VBIED), is an improvised explosive device designed to be detonated in an automobile or other vehicles.
Car bombs can be roughly divided into two main categories: those used primarily to kill the occupants of the vehicle (often as an assassination) and those used as a means to kill, injure or damage people and buildings outside the vehicle. The latter type may be parked (the vehicle disguising the bomb and allowing the bomber to leave the area), or the vehicle might be used to deliver the bomb (often as part of a suicide bombing).
It is commonly used as a weapon of terrorism or guerrilla warfare to kill people near the blast site or to damage buildings or other property. Car bombs act as their own delivery mechanisms and can carry a relatively large amount of explosives without attracting suspicion. In larger vehicles and trucks, weights of around 5,000 pounds (2,300 kg) or more have been used, for example, in the Oklahoma City bombing. Car bombs are activated in a variety of ways, including opening the vehicle's doors, starting the engine, remote detonation, depressing the accelerator or brake pedals, or simply lighting a fuse or setting a timing device. The gasoline in the vehicle's fuel tank may make the explosion of the bomb more powerful by dispersing and igniting the fuel.
Car bombs have been used for attacks motivated by a wide variety of grievances and ideologies, by people and groups from a wide variety of cultural and religious backgrounds: nationalist, republican, left wing, right wing, Jewish, Christian, Muslim, and others.
Car bombs are preceded by the 16th century hellburners, explosive-laden ships which were used to deadly effect by the besieged Dutch forces in Antwerp against the besieging Spanish. Though using a less refined technology, the basic principle of the hellburner is similar to that of the car bomb.
The first car bomb may have been the one used for the assassination attempt on Ottoman Sultan Abdul Hamid II in 1905 in Istanbul by Armenian separatists in the command of Papken Siuni belonging to the Armenian Revolutionary Federation.
Car bombs were also preceded by animal bombs using horses and cows, then eventually emerging into car use.
Prior to the 20th century, bombs planted in horse carts had been used in assassination plots, notably the unsuccessful "machine infernale" attempt to kill Napoleon on 24 December 1800.
Mario Buda's improvised wagon used in the 1920 Wall Street bombing is considered a prototype of the car bomb.
The first reported car bombing was the Bath School bombings in Michigan, USA in 1927. Multiple separate explosions on the same day killed 45 people, including the bomber, and half of a school was destroyed.
The bombings were all carried out by Andrew Kehoe, motivated by a personal grievance.
His death was possibly an intentional suicide, but the cause of the explosion was a gun shot that might not have been intended to set off the load. The explosion itself did not seem to form part of a suicide attack on a specific planned target other than possibly himself and his truck.
The explosives in his truck detonated when he saw two men nearby had a gun, after he set off multiple other bombs.
The explosion may have been set off indirectly by him firing his own gun at the men.
Most of the deaths were caused by the earlier bombs.
Some groups in Palestine have used both cars and donkeys.
The Irgun, a Zionist militant group in British controlled Palestine, used donkeys in two attacks on Haifa vegetable market in 1939. The donkeys were loaded with explosives to attack the market, one attack killed 78 people, the other killed 21 people and wounded 24.
The previous year the Irgun attacked the market with a car bomb, killing 35 Arab civilians and wounding 70. There are no clearly documented cases of the Irgun using car bombs in suicide attacks, but the Irgun and their extremist Lehi splinter group used suicide in other circumstances and are seen as the key developers of car bombs, that were later used by other groups in numerous suicide attacks.