Car bombs have, over the past two years, become the favorite weapon of terrorists in Iraq. Since July 2003, when the first one was used, there have been (as of June 5th) 278 such attacks. These caused 9,167 casualties (2,818 people dead, 6,349 wounded.) Thats an average of 33 casualties per car bomb. Not all were suicide car bombs, 42 percent were set off by remote control. Nearly all the drivers of the suicide car bombs have been foreign Arabs, mainly from Saudi Arabia. The worst month ever for car bombs was May, 2005, with 32 attacks and 1,300 casualties. This was not the largest number of attacks (that was in September, 2004, with 34), but it was the largest number of casualties. The Sunni Arabs preferred the roadside bomb, 20-30 a day being used against coalition and Iraqi forces. Currently, only about a quarter of those bombs actually do any damage to American and Iraqi troops, the rest are discovered first. 

Car bombs really got going in early 2004, when Iraqi terrorists (Sunni Arabs, particularly former Saddam thugs) joined forces with al Qaeda. The Sunni Arabs had the money and the connections (with Sunni Arab tribal and religious leaders) to build lots of car bombs. All that was required was money (the Saddam crowd had lots of that), and explosives (Iraq was overflowing with the stuff). Pay the money to a garage owned by Sunni Arabs and you get a car bomb, and some Sunni Arabs grateful for the work. Building car bombs paid well, up to $20,000 per job (usually using a stolen car). If the car bomb could not be parked, and then set off by remote control or timer, al Qaeda could provide a suicide volunteer, willing to drive the car, and detonate the explosives at the most appropriate place. 

Better yet, it didnt take a lot of organization to carry out a terrorist campaign with car bombs. Once the Sunni Arab and al Qaeda leaders agreed on what types of targets to go after, the bagmen were dispatched to deliver the money to the bomb builders. When the car bombs were ready, delivery teams picked it up and delivered it. This meant parking the car as close to the target as possible, getting out of the way, and setting it off. The suicide car bombs were used for the more difficult targets, like those that did not allow just anyone to park a car in the area. Suicide car bombs were also preferred for use against moving targets (military or police patrols or convoys.) 

Your average car bomb had several hundred pounds of explosives, either in the form of artillery or mortar shells, or bulk explosives. Detonators on the shells, or stuck into the blocks of explosives, were connected to a electromechanical switch, a wireless device or a timer. The quality of the car bombs kept improving until about a year ago, then it began to decline, as more and more garage owners and mechanics backed away from the car bomb business. Hundreds of these guys were getting busted, and any property or tools they owned taken or destroyed. Baath raised the rates, but this wasnt worth the loss of property, or freedom (and months or years in jail.) So more amateurs got involved. This led to more duds and accidents (premature detonations.) Actually, it appears that some 500 car bombs have been built so far, with over 200 being seized, or destroyed, before they could be used. Several dozen such car bombs were taken, or bombed, in the November battle of Fallujah. 

Security around American military bases was always tight, and the car bombers were rarely able to even get close. In the last year, Iraqi government and police locations became just a difficult to get near. So the car bombs more frequently went off among civilians. This made the car bombers, and the people behind them, increasingly unpopular. That became a growing problem. It was harder to keep car bomb building, and the activities of the delivery teams, secret. Most Iraqis wanted nothing to do with the car bombers, now that just about anyone could become a victim. Many Iraqis began reporting suspicious activity, that might involve car bombs. The result has been less well constructed car bombs, and less reliable delivery teams. The operation is more dependent on al Qaeda supplied suicide drivers. Even the quality of these volunteers has declined, with several later identified as retarded, and apparently convinced to do something the martyrs could not really understand. 

One thing thats made it easier for the car bombers has been the explosive growth in car ownership in the last year. The Iraqi economy is booming, and that means lots more vehicles on the roads. Thus its easier for the car bombs to just get lost in the traffic. It also means many exasperated, or nervous, suicide bombers setting off their explosives while stuck in a traffic jam. Traffic is becoming a more important factor for terrorists, as much of the car bomb construction has been moved to rural areas, to avoid the attention of police informants. Thus the car bomb has to be moved longer distances, exposing it to greater chance of detection, or breakdown. 

The car bomb campaign will continue until nearly all Sunni Arabs refuse to support it. Al Qaeda cannot carry out many of these attacks on its own, because nearly all al Qaeda members in Iraq are foreigners. These people stand out in Iraq, and if known to be dangerous, turned in, or otherwise taken care of.