The vehicles were primarily used in two ways in Mosul. First, as a defensive tool: If advancing Iraqi forces broke through a certain barrier, they often were met with a barrage of the vehicles. The second use of the car bombs was more offensive in nature. They usually led the militants' attacks and, more often than not, were parked in alleys and garages to be used to ambush unsuspecting forces.
The homemade armor schemes protected the driver and the explosives arranged in the rear from small arms and rocket fire, forcing Iraqi troops to use heavier and subsequently slower weapons to target them. U.S. airstrikes were often unable to target the vehicles as they sped through the narrow streets of Mosul. Instead, aircraft would drop bombs to destroy parts of the road, making the vehicles swerve and slow down as they approached Iraqi lines.
The vehicles were anything but inconspicuous, so the terrorist group has since started painting the armor to make them blend in. In Syria, some have been seen with the shell of a vehicle bolted over the armor to make car bombs harder to spot.