SCATS is an Australian developed adaptive Urban Traffic Control system that has been in use since the late 1970's in Sydney and has now been deployed in over 70 cities around the world.
Recognised for its adaptive nature to make sure that traffic is moved in the most efficient manner possible given the constraint of limited capacity road in highly urbanised cities such as Sydney, Australia.
SCATS - Sydney Co-ordinated Adaptive Traffic System
The link to the SCATS product site gives the reader a background in how it works and how it integrates with Public Transport systems with dedicated bus prioritisation corridors.
SCATS developed its "view" of traffic by gathering vehicle count data in real time and would form a view where the majority of "demand" for time would be. SCATS then executes changes to each intersection's "cycle time" to ensure that a little more time is given to roads where the vehicle count is consistently greatest until it is reduced to more normal levels.
The process of changing an intersection's cycle time is the "adaptive" part of Urban Traffic Control and essentially works to clear the traffic in a particular direction.
When SCATS was first deployed it made use of dedicated "leased lines" also known as "permanently attached private lines (PAPL), and in fact, the SCATS monitoring system was deployed by having a Central Manager at the top of the computing model and one or more Regional Computers (RC). The Regional Computer has the responsibility of communicating with each intersection's Traffic Signal Controller.
A Traffic Signal Controller is the traffic signalling device that "counts" the number of vehicles on the roads, as well as "driving" the traffic lights.
Having a hierarchical model means that the SCATS "monitoring" network has several layers of redundancy, as the Central Manager forms a high level view of the "whole city's traffic flows". The Regional Computer monitoring a local region and is the primary engine changing the cycle time in accordance with special queuing theory algorithms so it forms a more "regional view" of traffic flow.
So in essence the data flow is: Traffic Signal Controller -> Regional Computer -> Central Manager.
What is important here is that in the event that any one of these communication connections is broken, there is no major effect on the continuation of traffic control. Once communications is re-established then the SCATS system exercises its control over the local road intersection by commanding and changing the cycle times to achieve coordination between adjacent intersections.
This also means SCATS has an in-built disaster recovery mechanism because the Regional Computers can be physically spread around the city, so in the event of the Central Manager computer being unavailable, the Regional Computer will continue to exercise effective coordination for its given regional road network.
SCATS is distributed by ATC in Sydney Australia and has experts in the implementation and optimisation of SCATS systems.
Recognised for its adaptive nature to make sure that traffic is moved in the most efficient manner possible given the constraint of limited capacity road in highly urbanised cities such as Sydney, Australia.
SCATS - Sydney Co-ordinated Adaptive Traffic System
The link to the SCATS product site gives the reader a background in how it works and how it integrates with Public Transport systems with dedicated bus prioritisation corridors.
SCATS developed its "view" of traffic by gathering vehicle count data in real time and would form a view where the majority of "demand" for time would be. SCATS then executes changes to each intersection's "cycle time" to ensure that a little more time is given to roads where the vehicle count is consistently greatest until it is reduced to more normal levels.
The process of changing an intersection's cycle time is the "adaptive" part of Urban Traffic Control and essentially works to clear the traffic in a particular direction.
When SCATS was first deployed it made use of dedicated "leased lines" also known as "permanently attached private lines (PAPL), and in fact, the SCATS monitoring system was deployed by having a Central Manager at the top of the computing model and one or more Regional Computers (RC). The Regional Computer has the responsibility of communicating with each intersection's Traffic Signal Controller.
A Traffic Signal Controller is the traffic signalling device that "counts" the number of vehicles on the roads, as well as "driving" the traffic lights.
Having a hierarchical model means that the SCATS "monitoring" network has several layers of redundancy, as the Central Manager forms a high level view of the "whole city's traffic flows". The Regional Computer monitoring a local region and is the primary engine changing the cycle time in accordance with special queuing theory algorithms so it forms a more "regional view" of traffic flow.
So in essence the data flow is: Traffic Signal Controller -> Regional Computer -> Central Manager.
What is important here is that in the event that any one of these communication connections is broken, there is no major effect on the continuation of traffic control. Once communications is re-established then the SCATS system exercises its control over the local road intersection by commanding and changing the cycle times to achieve coordination between adjacent intersections.
This also means SCATS has an in-built disaster recovery mechanism because the Regional Computers can be physically spread around the city, so in the event of the Central Manager computer being unavailable, the Regional Computer will continue to exercise effective coordination for its given regional road network.
SCATS is distributed by ATC in Sydney Australia and has experts in the implementation and optimisation of SCATS systems.
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