Traffic Light Control and Coordination - Other Types of Control

Other Types of Control

• Failures: If power is still available, a flashing amber light is used to warn of an intersection. Methods to distinguish the main road from the secondary road (and hence right of way) include using yield (give way) signs, stop signs or a flashing red light on the secondary road as well as written signage. In some countries including Australia, the road rules outline procedures such as giving way to the right.
• Part-time operation: Some traffic lights will not operate at night or when traffic is very light. Some may only operate at particular set times (e.g. during working hours of a major factory) or only during special events such as sports or exhibitions. When not operating, the same measures as with failures are used. Part-time operation has advantages and disadvantages.
• Railroad preemption: Traffic signals are activated to coincide with the approach of a train, often where the intersection is near a rail crossing. See also Railroad preemption
• Bus and Transport Priority: Traffic signals are activated to coincide with the arrival of a bus or tram along a busway, bus lane or tramway. See also Bus priority
• Emergency Vehicles Some lights outside of fire or rescue stations have no green, as they may turn only amber and then red when fire trucks, ambulances, or other emergency vehicles of the like are exiting the station en route to an emergency. See also Traffic signal preemption