Roadside bombs have been the major cause of American, and Iraqi civilian, casualties in Iraq. Part of this is do their widespread use against American support troops, who comprise over 80 percent of the forces over there. Some 90 percent of IEDs are found or otherwise disabled before they can be used. But the Iraqis building them are not stupid. They keep coming up with new designs, and ways to use them.
IEDs started out as roadside bombs, the same kind of weapons encountered in Vietnam. But cell phones, and other wireless devices made them more lethal, and the many ammo dumps abandoned by Saddams troops provided plentiful raw materials. The U.S. Army gave them a new name; IED (Improvised Explosive Device.) This led to variations, and more acronyms. Radio Controlled (RCIED) include a wide variety of devices have been found: car key systems, remote door bells, cell phones, etc. Vehicle Borne (VBIED) can be very large, usually suicide missions. Victim Operated (VOIED) better known as booby traps. The original wire detonated version has no acronym, and is apparently becoming less popular, as the guy pushing the button has to be nearby. Hostile Iraqis tend to stay as far away from armed American as possible.
While American troops have gotten very good at finding and defusing IEDs, the ten percent or so they do not avoid continue to cause casualties. There's also a "Darwinian" evolution of IEDs and defensive measures. Soon after new defensive measures are adopted, the Iraqis come up with new twists on IED design or employment. One recent trick is to locate them off the ground, on poles, roofs, guard rails. This increases the lethal area. And the higher up ones also have the advantage of hitting vehicles from the top.
About a third of radio controlled devices may be subject to some sort of jamming, and truck convoys routinely move with portable jamming devices turned on. There may be more that have been disabled, because an IED is not positively identified unless it goes off, or is seen and disabled by engineers. Iraqis are unhappy with this jamming, as it tends to disrupt cell phone service.
Its also suspected that some types of radio controlled devices may be subject to electronic interference that sets them off prematurely. The U.S. Army has conducted experiments in this area, and one incident, in Yuma, Arizona, resulted in malfunctions to garage doors, car alarms systems, remote door bell systems, and other remote electronic devices when the jamming device was apparently tested at too high a power level. The Israelis have long produced jammers that do this, and much of this Israeli technology finds its way into American military equipment (and vice versa.)