STREAMS Integrated Intelligent Transport System

STREAMS® Integrated Intelligent Transport System is an enterprise traffic management system designed to operate in the Microsoft Windows environment. Like most traffic management systems, STREAMS® is an array of institutional, human, hardware, and software components designed to monitor, control, and manage traffic on streets and highways. Advanced traffic management systems come under the banner of ITS (intelligent transport systems). ITS is an umbrella term referring to the application of information and communications technology to transport operations in order to reduce operating costs, improve safety and maximise the capacity of existing infrastructure. STREAMS® provides traffic signal management, incident management, motorway management, vehicle priority, traveller information and parking guidance within a single integrated system.[1] STREAMS® is developed by Transmax®.

History

In 1969, the Department of Main Roads (Queensland) installed the first Intelligent Transport System in Australia (located at Surfers Paradise). This included 30 signalised intersections featuring centralised control and traffic responsive capabilities.

In 1985, a second generation traffic management system was installed in Cairns, Australia. This was known as the TRAC System, or Traffic Responsive Adaptive Control System. Progressive installation of the TRAC system followed at several more sites around Queensland including the capital city, Brisbane.

In 1988, a traffic management system was installed for the South East Freeway in Brisbane, Australia. The features included were ramp metering and graphical displays of traffic conditions. It also provided automatic incident detection.

In 1992, a new integrated intelligent transport system development was commenced. The objectives were to lower ongoing costs while providing increased performance and opportunity for future ITS applications. The resulting system was STREAMS®.

In 2002, the division of Department of Main Roads (Queensland) responsible for continuing development of STREAMS® was privatised to form Transmax. The company remains 100% owned by the Queensland Government Department of Transport and Main Roads.

In April 2007, Transmax® in partnership with VicRoads implemented a coordinated ramp metering trial in Melbourne, Victoria on a 15 km section of the Monash Freeway. Later that year, in December, VicRoads installed STREAMS® to manage another six ramps.[2]

These developments were part of a much larger M1 Upgrade Project that continued over the next three years, eventually winning the 2010 National ITS Australia Award. The project to upgrade the 75-kilometre M1 Freeway, increased the capacity and safety of the Monash Freeway, the CityLink Tollway (Southern Link) and the West Gate Freeway utilising STREAMS® as the Integrated Control System.[3]

Software Architecture

STREAMS® employs a distributed computing software architecture. Field hardware such as intersection controllers, video cameras and speed detectors are connected via field processors back to a central application server. Users connect to the application server via the workstation software. Field communications are via Optical Fibre, DSL, Wireless or PAPL connections.

The software is built in distinct modules for each distinct area of traffic / transport control and monitoring. The workstation software communicates to the application server software via a publisher / subscriber model (i.e. workstations subscribe to specifically requested streams of data which are published by the application server).

The software architecture model is designed to support the software's claim of being an "integrated" Advanced Traffic Management System. This breaks away from the inter-operability model, which is multiple ITS systems working in parallel, each performing a discrete function.

The workstation software is built around a central user interface called "STREAMS® Explorer". Other specification / reporting applications can all be launched from STREAMS® Explorer.

The transport network data is set up via a GIS (Geographic Information System). The GIS allows for a graphical user interface displaying transport network data overlaid on street maps and updating in real-time.

Adaptive Traffic Management

STREAMS® implements adaptive traffic management through a feature called "Dynamic Plan Selection". Depending on the density of traffic (occupancy) and the dominant direction of traffic (for example, inbound, outbound, or bidirectional) on a road, nearby signalised intersections are operated using several predefined traffic plans. A user sets up the signal timing, and picks the traffic density levels and direction that they apply to. Selecting the appropriate signal timing is then automatic. When a time based traffic plan schedule would be inappropriate because of varying traffic levels, STREAMS® Dynamic Plan Selection can adapt to unexpected traffic levels as they arise.

With help from the academic community, STREAMS® Managed Motorways offers the coordinated ramp-metering algorithm suite ALINEA/HERO. The modular architecture of STREAMS® allows Transmax® to integrate new algorithms as they become available. STREAMS® applies the computed metering rates using ramp signal controllers deployed at the roadside. Controlling multiple consecutive ramps, ideally the whole motorway, makes it possible to maintain a more consistent motorway flow and prevent flow breakdown. Using HERO, STREAMS® is able to balance queues across multiple ramps and maximise motorway performance.

See also

References

  1. ↑ "Improved travel time reliability for Sandgate Road and Mains Road traffic", Queensland Department of Main Roads Statement, 21 September 2008
  2. ↑ "On-ramp to success", Traffic Technology International, October–November 2009
  3. ↑ Melbourne’s M1 freeway upgrade and SUNA Traffic Channel win ITS Australia Awards

Further reading

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