Heysen Tunnels Management System

The Heysen Tunnels run beneath Eagle on the Hill cutting 2 kilometres off the Mt Barker Road and bypassing the stretch between Devils Elbow and Eagle on the Hill. One tunnel is city-bound and the other is hills-bound (also referred to as Adelaide-bound and Crafers-bound).

Each tunnel

• is 500 metres long
• is 10.5 metres wide
• has 3 lanes each 3.5 metres wide
• has 90 km speed limit
• takes about 20 seconds to drive through.

Traffic management and surveillance

Cameras

• Incident detection cameras detect stopped and slow moving vehicles and alert operators in the Traffic Control Centre of problems inside the tunnels.
• Adjustable video surveillance cameras monitor all activities inside tunnels.
• Cameras inside cross passageways monitor activity in an event of an emergency.

Electric overheight vehicle detector signs at the entrance of each tunnel detect overheight vehicles and flash yellow signals when overheight vehicle is identified.

Lane use signals alter the use of lanes within the tunnels during emergencies or lane restrictions.

Variable message signs notify and advise motorists of unexpected conditions within the tunnels such as maintenance or vehicle breakdowns.

Tunnel control systems

• SCADA (Supervisory Control and Data Acquisition) control system gathers information and issues on a range of operational decisions which can be quickly passed to the police, fire brigade or ambulance services.
• SCADA also monitors the fire detection systems, the air sampling system, lighting levels, fan operation and traffic flow.
• SCADA is housed in a control building at the tunnels and is connected to Transport SA’s Traffic Control Centre in Norwood by fibre optic link.
  

Tunnel safety features

Zoned lighting system was designed especially for the tunnels to provide for the safe entry of vehicles into tunnels at the regulatory speed. A luminance sensor mounted near the entrance portals is used to stage the tunnel lights to match exterior conditions and prevent dazzling or blinding drivers due to a bright light at night or a gloomy interior lighting during the day time.

Wall panels enhance the reflection of the interior light and reduce the number of light fittings required reducing electricity costs.

Visibility monitors measure the visibility for motorists within the tunnels and automatically activate exhaust fans to improve the visibility when required.

Gas monitoring / analyser monitors the level of carbon monoxide and nitrous oxide emitted via the exhaust fumes and activates the exhaust fans to clear and maintain air quality and visibility.

Jet exhaust fans can be independently switched to allow the operation of one or more pairs of fans to reduce the exhaust gas concentration to an acceptable level. These fans generate a thrust that can propel air along the tunnel in either direction.

11 emergency phones in each tunnel plus one phone in each cross passageway place calls direct to Transport SA’s Traffic Control Centre.

Emergency lighting operates if the mains power supplies fail. If the power failure persists, the tunnel management system can introduce traffic speed controls to match a safe driving speed with the available light level.

Fire safety system includes fire extinguishers and hoses located in cabinets within the tunnel walls. An emergency break glass system calls the fire brigade. Thermal detectors along the tunnel roof locate the heat source in each tunnel and automatically call fire services and the Traffic Control Centre. Two large storage tanks above the tunnel provide the water supply for the hydrants to use on larger fires.

3 emergency pedestrian cross passageways connect the two tunnels. They allow people to walk through a fire rated door to the clear tunnel in the event of a fire or emergency in either tunnel.

Public address system gives traffic redirection in emergency situations.

Radio re-broadcast system allows emergency radios (ambulance, fire, police) and broadcast (commercial) radio to be received within the tunnel. Aerials located in the tunnel connected to receivers/transmitters outside ensure a good standard of service.

Alarm monitoring system monitors the state of all devices and equipment and raises an alarm for any equipment failures or faults.

Back up power system. Tunnels receive electrical supply from both ends. Supply can be maintained in the event of a power failure from either end. A standby generator makes sure that all safety monitoring features within tunnels are maintained at all times.