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Traffic lights …

- - - - The traffic signal controller is a computer that is regarded as the 'brain' of the system. It is located on the corner of the intersection or crossing and is in a metal box. Information from the detector loops and the pedestrian push button are received and processed by the traffic signal controller. The duration of the green signal at the intersection/crossing as well as the transition from green to amber to red light is determined by the controller.
    - - Regular maintenance is required to ensure the traffic light system operates successfully as a whole.
        
        Potential relationship mismatch
        
        If the 'brain' of the system is broken or fails to operate then the rest of system will not be able to properley operate.
  - - - Vechicle detector loops and pedestrian push buttons are mechansims regarded as the 'eyes' of the system. The pedestrian push button is a signalling system used by pedestrians to indicate to the traffic signal controller that they wish to pass through the intersection/crossing and need the traffic signal changed so that they have right of way. A vechicle detector loop is designed to let the traffic signal controller know that a vechicle is waiting to go through the intersection. Vechicle loop detectors are loops of wire that are buried in the road and are located at the intersection near the stop line. The loop of wire creates a magnetic field when a car drives over it, causing the loop to change.
    - - Vechicle detector loops and pedestrian push buttons are installed by electrical technicians.
      - Traffic signal controller will not be notified if a pedestrian wishes to cross the intersection if the pedestrian does not use the pedestrian push button when they want to cross the intersection.
        
        Potential relationship mismatch
        
        If vechicle detector loops and pedestrian push buttons are not installed and used correctly, then the traffic light system will not operate correctly.
        
        Has it been tested for when there is substantial traffic congestion on the roads?
  - - - Traffic signal lanterns are directed by the traffic signal controller. It's purpose is to display signal colours such as red, amber, and green that let road users know when to go and when to stop. Traffic signals are also used for pedestrians when they wish to cross the intersection or crossing. A pedestrian signal will notify pedestrians when to and when not to cross by displaying a green (Go/Walk) or red (Stop/Don't walk) figure.
    - - Traffic signal lights are easy to see and read for road users and pedestrians. display colours (Red, amber and green) are vivid and bright during the day and night.
        
        Potential relationship mismatch
        
        If traffic signal lanterns do not operate correctly, road users and pedestrians will be unable to safely cross the intersection or crossing.
      - Traffic signal lanterns can become faulty and stop working without warning. This could potentially cause road accidents at intersections. Road users will need to be cautious at intersections until police arrive to safely direct and control the flow of traffic.
      - Regular maintenance required on traffic signal lanterns to ensure they still function and operate correctly.
  - - - Connects all the system parts together in order for it to properley function.
    - - Traffic light posts and pits are positioned in an area that is easily visible to road users and pedestrians without obstructing the road users and pedestrians view of the road or the traffic signal lanterns. Traffic light posts and pits are securely placed and are hard to remove or transport.
      - Below ground installed electrical cables for traffic lights are installed by electrical technicians.
        
        Potential relationship mismatch
        
        If there is failure to properely connect these system parts together, then the traffic light system as a whole will fail to properley operate.