Random checkpoint
（重定向自Checkstop）
A random checkpoint is a military and police tactic. In a military context, checkpoints involve the setup of a hasty roadblock by mobile truck- or armored vehicle-mounted infantry to disrupt unauthorized or unwanted movement or military activity and to check for valid identification and search for contraband, fugitives, or weapons that are not permitted in civilian hands. Random checkpoints are set up to achieve surprise, as opposed to known permanently located checkpoints, which suspects could circumvent. They are often established in locations where they cannot be observed by approaching traffic until it is too late to withdraw and escape without being observed.