U.S. Army hand and arm signals

[1] Visual signals are any means of communication that require sight and can be used to transmit prearranged messages rapidly over short distances.

Within this limitation, visual communication can become greatly disrupted during periods of poor visibility or when the terrain restricts clear observation.

[1] Leaders of dismounted units use arm and hand signals to control the movement of individuals, teams, and squads.

Leaders of mounted units use arm and hand signals to control individual vehicles and platoon movement.

When distances between vehicles increase, flags (wrapped and tied) can be used as an extension of the arm to give the signals.