A military police vehicle is any vehicle used by military police (MPs). When forward deployed, United States military police units customarily employ HMMWVs or M1117 Armored Security Vehicles. However, on larger installations, MPs assigned to on-post law enforcement duties may use military or civilian 4x4 vehicles. When operating at installations in the U.S., military police typically employ patrol cars similar to local police departments. Special agents of the U.S. Army Criminal Investigation Command or other military special investigation branches (such as the Special Investigation Branch of the Royal Military Police), may employ unmarked civilian vehicles in the course of their duties within the United States. These would often be the detective's own private car. In combat zones, these agents employ the same tactical vehicles as regular military police units.