Ngauranga Gorge
Response Plan Development
View up Ngauranga Gorge
View up the Gorge (click to enlarge)
Effective incident response plans and traffic management plans have been developed including: the “AM Peak Period Queue Procedure" which comprises a combination of warning signs and reduced speed limits to protect the back of the vehicle queue from potential rear end collisions.
The system is also used to convey public information including road closures and special events such as the Wellington Cuba Street Carnival, which have a direct impact on the State Highway.
One of the most important results of the integrated approach to incident management, is that a response can be actioned within 1 minute of the incident. This time typically comprises 15 seconds for automatic detection, 15 seconds to assess (verify) the incident using the automatically switched video image, and 30 seconds to classify the incident and action the response. By this time, warning messages and speed limits are in place and the response team alerted.
System Security
System security was important. During the design phase recommendations were made that a dedicated fibre optic cable be laid in the Gorge to reduce the likelihood of complete system failure. This decision proved to be the right one following a vehicle crash in the Gorge which resulted in one of the system controllers being entirely demolished. While some system functionality was lost the body of the system was retained.
Uninterrupted Power Supply (UPS) units were also installed in the signs to provide further system security. The UPS stabilises power in the event of power-spikes to prevent system damage and provides battery back-up for approximately 30 minutes during a power cut.
