The primary purpose of traffic control by light signals is to separate conflicting traffic by the division of time, within the available road space, in a safe, efficient and equitable manner. The term “traffic” includes all road users: vehicles, (including cycles), pedestrians and equestrians. Conflict at a junction is manifested as an increase in delay and/or accident rate.
At a signal-controlled junction, vehicular traffic is permitted to flow in a strictly controlled manner. The traffic flows, available road space, layout and stage