Glossary of Terms (ITS)

Document No:   
Revision:  1A
Date amended:  14-May-2015

The information below is intended to reflect the preferred practice of Main Roads Western Australia ("Main Roads"). Main Roads reserves the right to update this information at any time without notice. If you have any questions or comments please contact Bita Charehjooby e-mail or on (08) 9323 4439.

To the extent permitted by law, Main Roads, its employees, agents, authors and contributors are not liable for any loss resulting from any action taken or reliance made by you on the information herein displayed.

Revision Register

Ed/Version Number Clause Number Description of Revision Date
1 All  Guideline Developed  05-Nov-2011
​1A​Header​Guideline introduction amended.​14-May-2015


Table of Content


1.1 Intelligent Transport Systems

1.1.1. 3G / NextG
3G is generic term for a 'Third Generation' cellular wireless mobile telecommunications Network. (NextG is a third generation mobile network operated by Telstra in Australia). Main Roads uses this technology mainly for temporary connections, backup systems, or where the cost for a twisted pair to the ITS cabinet is deemed to be excessive, or where ADSL or fibre is unavailable.

1.1.2. ADSL
Asymmetric Digital Subscriber Line (ADSL) is a data communications technology using copper telephone lines. Main Roads uses this technology where a CCTV camera or UPS is to be installed at the signalised site, or the site is at a rail crossing, or where there is a general requirement for extra bandwidth. These lines utilise a twisted pair connection and are installed with 512 kbps download / 512 kbps upload speeds.

1.1.3. AMTS
Asset Management Traffic Systems branch.

1.1.4. Asset (A)
The electrical asset that is requiring the installation of a particular type of communications facility.

1.1.5. Asset (B)
The electrical asset that is close to asset (A) allowing for a direct connection.

1.1.6. Asset (C)
The electrical asset that potentially has a clear line of site from asset (A) for a wireless connection.

1.1.7. Bandwidth
Bandwidth is a measure of the rate of data transmission in a communications link or network. It is usually expressed in bits/second (bps) or its higher multiples (e.g. kilobits/s, megabits/s). It can also refer to a total data bit rate over a given period (e.g. gigabits per month).

1.1.8. BDSL
Business Digital Subscriber Line (BDSL) is the same type of connection as ADSL but with the available bandwidth ranging from 512 kbps to 4 Mbps. Main Roads uses this technology where a greater number of devices or several ITS sites are needed to be connected.

1.1.9. Closed Circuit Television (CCTV) camera
CCTV cameras are used by Main Roads to monitor traffic in 'real time' in order to better manage traffic flows and incidents.

1.1.10. Communications
Communications between devices at ITS sites and another location (usually the Traffic Operations Centre- TOC) allows the transfer of data, and provides the ability to monitor and control these devices remotely.

1.1.11. Dataplex
The Dataplex 'solution' utilises twisted pair copper cables for data transmission. It can be installed where the traffic signal controller is close to a SCATS Regional Computer, i.e. at a distance of less than 6 km. The Dataplex system utilises a single twisted pair connection between a Dataplex modem and Dataplex Multiplexer - the modem plugs into the traffic signal controller, and the Multiplexer is plugged into the SCATS network, usually inside an ITS Communications cabin.

1.1.12. Ethernet, Serial (RS-232, RS-485)
These are forms of serial data transmission.  ITS sites in close proximity to an ADSL connection, ITS cabin or SCATS Regional Computer location can be directly connected into the communications network via Cat5-e or Cat6 Ethernet cable, or via RS-232/485 serial links.

1.1.13. Intelligent Transport Systems (ITS)
A broad range of communications-based information, control, and electronics technologies integrated into the transportation system infrastructure, and in vehicles, to help monitor and manage traffic flow, reduce congestion, provide alternate routes to travellers, enhance productivity, and save lives, time, and money.

1.1.14. LGA
Local Government Association.

1.1.15. Modem
A modem (modulator-demodulator) is a communications device that modulates an analogue carrier signal for the transmission of digital information. Main Roads uses modems to transmit SCATS data, CCTV footage, etc. over communication lines.

1.1.16. Optic Fibre
Optical Fibre refers to the technology associated with the transmission of information (e.g. ITS data) as light pulses along glass cored fibre cables. Sites located in the vicinity of Main Roads' optic fibre 'backbone' should be connected directly to that fibre for device communications.  The connection of the device to the 'backbone' is usually via an underground pit.

1.1.17. PSTN
The Public Switched Telephone Network (PSTN) is the original Telstra copper based network provided for voice grade communications.  It can provide data transmission at a speed of 64 kbps.  Main Roads ITS devices (including traffic signals) connected by PSTN normally operate in a permanently 'dialled-up' mode. This type of service is installed when there are no other systems utilising the bandwidth, other than the traffic signals themselves.

1.1.18. Radio Frequency (RF)
RF connections can be considered where the cost for a twisted pair cable connection to the traffic signal controller is deemed to be excessive, or where good line of sight exists between the traffic signals and an existing RF Base Station. If no base station exists in the vicinity, it may be possible to install one, especially if there are several intersections in close proximity.

1.1.19. SDM
Systems Development Manager.

1.1.20. SIM Card and Plan
A sim card and plan is required for 3G / NextG services to provide a unique identity and to allocate the amount of bandwidth available per month.

1.1.21. Sydney Coordinated Adaptive Traffic System (SCATS)
SCATS is a fully-adaptive wide area traffic control system developed in Australia and adopted in many cities around the world to control and monitor traffic signals.

1.1.22. Traffic Signal Controller (TSC) 
An automatic device that regulates the sequence and duration of the illumination of aspects at a traffic signalised site.

1.1.23. TSOO
Traffic Systems Operation Officer.

1.1.24. Twisted Pair
A type of cable that consists of two independently insulated wires twisted together. This arrangement of conductors helps to reduce crosstalk and electromagnetic induction.

1.1.25. UPS    
An Uninterruptible Power Supply uses batteries to supply power in the event of a disruption to the mains power.

1.1.26. Variable Message Sign (VMS)
These are electronic signs that can be used to display a wide range of messages to alert drivers of on-road incidents on the road ahead. They are also used to warn road users about weather conditions and other important information.

1.1.27. Variable Speed Limit (VSL)
Variable speed limits are speed limits that change based on road, traffic and weather conditions. Electronic VSL Signs display the applicable speed limit.

1.1.28. Vehicle Detection Station (VDS)
Vehicle detection stations provide vehicle counts, average vehicle speeds and vehicle occupancy for a stretch of road.