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A small town is piloting an experimental traffic light control system aimed at improving emergency vehicle response times. To help emergency vehicle drivers pass traffic lights more quickly, devices have been installed on traffic lights as well as embedded in the town’s emergency vehicle navigation systems (police, fire & ambulance). The traffic light devices use Radio Frequency (RF) signals sent from the in-car devices to identify each vehicle. When authorised in-car devices are manually triggered, those traffic lights within range which govern the vehicle’s forward motion are signalled to, as quickly as possible, safely switch to green.
(a).
Outline how, upon receiving a change signal from an authorised emergency vehicle, the sensors, actuators and microprocessors on the traffic light devices operate.
[4](b).
Given the emergency traffic light control systems forms an open loop system, outline one way in which traffic light operations may return to normal following an emergency trigger event.
[1]Rather than triggering traffic lights manually via emergency vehicle consoles, an alternative proposal suggests traffic lights should instead be controlled by a centralised computer dispatch system.
(c).
Discuss both the advantages and disadvantages of a traffic light control system operated via a central computer dispatch system (centralised) in contrast to a driver controlled (distributed) manual trigger system.
[5]In an effort to better understand traffic flows in the city, the control devices installed on traffic lights were upgraded to include CCTV cameras.
(d).
Discuss the social implications of monitoring traffic using CCTV.
[3]
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