Intelligent transportation systems are in use all over the world, trying to provide the best possible traffic flow, and Sydney is no exception. Like many cities, the system in Sydney has a name, the Sydney Coordinated Adaptive Traffic System, abbreviated to SCATS. It is an intelligent transportation system that collects information from sensors stationed all over the city. Vehicles are sensed by a series of inductive loops installed underneath the tarmac, which provide information on traffic volume and speed, which allow the SCATS system to calculate and alter the sequencing of traffic lights across the network. It also uses input from pedestrians, who provide information unknowingly, every time they push the button at a pedestrian crossing. The whole thing operates from an automatic plan selection, which uses the data collected, to reference a library in response to the data being provided in real time.
Local and Master Operation
SCATS works at a local and a master level, with local data being provided from roadside control boxes, which operate the sequence changes on signals, and collects information on the traffic passing from the vehicle detectors in the road. This information is then sent to the Master control through a range of different protocols, such as ADSL, PSTN and a network of private cables, dedicated to the traffic system and not involving any telecommunications support. The master is a remote computer, which collates the data and uses it to provide area and urban traffic control. The local and master systems communicate continually not just about the traffic, but its own operational activity, so that if a signal is experiencing a problem, the master system knows of it instantly and can organise immediate repair works.
Keeping the System Current
The management of SCATS realise the system will never be perfect and periodically run a Smart Traffic Review to assess performance, and technology is providing predictive techniques that will allow advanced modelling which can be compared to historical data in the systems library. So the signals and variable messaging boards around Sydney will become more efficient as the systems intelligence grows.
Organising Traffic Priority
The lights turning green for a bus that just rolled up to them is not a coincidence. This is due to SCATS having a priority system in place, which will allow certain vehicles to proceed faster than others. When it opens in Sydney next year, it will provide the new tram running from the CBD to Kensington and Randwick, with the highest level of priority, with the idea of allowing it to pass through intersections, without having to actually stop. Given the tram can carry over 400 people at a time, which means masses of people can get to work, school or college swiftly, while those using the car, will have to sit back and wait, as they have a much lower ranking in the systems priorities, while buses which now get priority, will shift to a medium level, though still ahead of the car.
While traffic may still be very heavy, especially at peak times of day, the system is doing its best to get you to your destination far swifter than you probably would without it.
Additionally, predictive techniques are being developed to allow advanced modelling and comparison with historical baseline data.