Personal armor for troops in Iraq is in the headlines once more. Side armor, which adds about ten pounds to the 16 pound weight of the Interceptor Protective Vest, has been available since 2003 (when 250 sets were sent to Iraq.) About a thousand sets were delivered in 2004, and more last year. Side armor is obviously not new, as many news stories imply. While the side armor provided useful protection, the added weight (for a trooper already carrying over fifty pounds), and restricts movement. The new armor is most popular with troops guarding convoys. They spend most of their time sitting down, and the side armor provides additional protection from roadside bombs, which throw out a lot of fragments, at troops sitting facing forward. The bombs are often accompanied by an ambush force armed with machine-guns and assault rifles. Sometimes, the troops have to get out of their vehicles and battle the ambushers. This is often intense and disorganized combat, with fire coming from all directions. Again, the side armor can be very useful, and the troops won't be running around so long that the additional weight and movement restriction will become a major problem. For the same reason, combat troops that are spending most of their time in their vehicles, don't mind the disadvantages of the side armor. But infantry that are spending a lot of time running around, up stairs and battling the enemy in an urban environment, nimbleness is more important. Some of these guys have been known to leave the back plate out, just to save a few pounds.
These different attitudes towards how much armor to wear are similar to those found in police forces. That's why the police have both lightweight armor (worn by most cops, most of the time) and heavier rigs for SWAT teams or anyone out on a raid, and even heavier getup for bomb disposal personnel.