For a start…
UK, CAP493, Section 2 Chapter 1:
2.1 Aerodrome Control shall issue information and instructions to aircraft under its control to achieve a safe, orderly and expeditious flow of air traffic with the objective of:
(1) Preventing collisions between:
(a) aircraft flying in, and in the vicinity of, the ATZ;
(b) aircraft taking-off and landing;
(c) aircraft and vehicles, obstructions and other aircraft on the manoeuvring area.
Note: Aerodrome Control is not solely responsible for the prevention of collisions. Pilots and vehicle drivers must also fulfil their own responsibilities in accordance with Rules of the Air.
(2) Assist in preventing collisions between aircraft on the apron.
My bold...