Simon Harrod / Regional Market Manager / Vaisala / , Australian Bridge Deck Heating System Controlled by Vaisala Ice Detection

Australia – “a land of sweeping plains, of ragged In , the winds from the north east down to the mountain ranges, of droughts and flooding south west providing extended regions of up to 600 meters in elevation that rains”. No mention of frost, ice nor snow in the major roads traverse. One such road is the Calder Freeway; the main arterial iconic poem by Dorothea McKellar dedicated between Melbourne and , with average daily vehicle volumes exceed- to a country that is known around the world for ing 10,000 vehicles per day. The roads in the Calder corridor warm weather and fine beaches. However, each have been upgraded and improved in a number of ways over the years, cul- winter in the south eastern states of Australia, minating in the dual carriage Calder Freeway that serves the area today. the climate is conducive to a combination of Prior to the current Calder Freeway, the old Calder marginal winter weather conditions which wound its way through numerous country towns on its way north to present hazardous road conditions for drivers. Bendigo. To the south of Woodend, it passes through the Black Forest, the most eastern section of the Wombat State Forest. It was here that the first Vaisala Ice Warning systems were installed in 1989, utilising pavement

The bridge deck heating coils were installed during construction

10 184/2010 based road sensors. The systems are still in operation today, activating local warning signs to alert drivers of hazardous conditions.

Ice Detection and Control System to Determine Hazardous Conditions

The winter conditions were taken into account during the design of the new Calder Freeway. VicRoads, the highway department for the state of Victoria, installed bridge deck heating in eight dual span bridges in the Macedon to section of the Freeway during the construction phase. Warning signs along the Calder Freeway alert drivers on icy conditions. The Bridge Deck Heating consists of three separate heating coils that non-invasive road weather sensors tation and testing was a given. are laid into the base of the bridge (Vaisala Remote Road Surface State Throughout the project, Vaisala acted deck prior to the construction of Sensor DSC111) were chosen to avoid as the central co-ordination point the road surface. A heating control causing damage to the heating coils. between the electrical contractor, system is then used to manage The project began in March 2008. VicRoads Regional Office, VicRoads the delivery of up to 160 Kwatts of During the first winter, the system Traffic Management Centre and heating per bridge deck to prevent was installed and commissioned, VicRoads ITS project group. and remove frost, ice and snow and the collection of data began. An Extensive system testing was also hazards from the bridge decks. The optimisation phase followed, during carried out by the VicRoads North- heating control system determines which the gathered data was anal- ern Region office, with numerous how many of the heating coils to ysed and used to adjust the software field staff involved in the checking of apply power to and for what period configuration prior to winter 2009. sign and heating operation. of time heating is required. A total of 13 detection sites were In summarising the project and In 2008, Vaisala was contracted installed, each connected to a process- its outcomes, the VicRoads Northern by VicRoads to implement an ice ing unit (Vaisala HydroMet™ System Region states: detection and control system to MAWS110), which uses the sensor data “The scope of the project was to determine the onset of hazardous to activate the appropriate heat setting refurbish the existing system in 2008 conditions, activate driver advisory from a three-stage heating system. and to deliver a reliable and stable warning signs, and manage the The configurability of the Ice Warning System. The improve- heating control. Whilst the system MAWS110 enabled a number of ments provided by the Vaisala is completely autonomous, it also important features to be imple- technology and its importance to the communicates with VicRoads Traffic mented, such as VicRoads RMS Calder corridor cannot be underes- Management Centre (TMC) to enable communication protocol between the timated. The solution, including ice the current status of detection, field sites and the Traffic Manage- detection, automatic warning sign warning signs and heating to be avail- ment Centre, the capability to log and bridge deck heating operation, is able throughout the organisation. one minute road weather conditions, providing all road users with reliable sign and heating status on site for the and up to the minute information Benefits from entire winter, and integrating existing about the local road condition.” Remote Sensors embedded temperature sensors to “The value of having such and Configurable the system. systems in place, especially during Processing Unit winter when adverse weather condi- Final Outcome: Vital tions in the vicinity of the Calder Implementing ice detection on the Improvement to Local corridor are high during the colder heated bridge decks with tradi- Road Conditions months, is vital for the confidence of tional pavement based sensors was the local communities, as well as all difficult due to the presence of the Due to the customised nature of the road users.“ embedded heating loops. Vaisala’s system, comprehensive documen-

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