I remembered that from another server i played.
It's like a square of barricades which police can spawn when on a crime scene
Like example you type /barricade and it spawns a square a peremiter of 200 metters. Which wont allow cars to go throught and would be .
And then you can type /removebarricade to remove it
It would give us a big advantage in crime scenes and a good way to block people from coming in. Like in Real life when they make barrage so people can't come
Im not sure if you understand what i mean but anyways.