Changes to signals brings improved traffic mngmnt.
Auckland Regional Office
11 June 2003
Changes to signals brings improved traffic management
Electronic signals have been used on the Auckland Harbour Bridge and its approaches since 1985 when green arrows and red crosses were introduced to show motorists which lanes were open and which were closed.
Since then, there have been considerable changes to traffic management on Auckland’s motorway network, including the introduction of the Moveable Lane Barrier in 1990 and the ongoing development of Transit New Zealand’s Advanced Traffic Management System (ATMS).
The ATMS comprises seven variable message signs, 35 TV cameras connected to a closed circuit television system, and 84 lane control signals positioned on 20 gantries – the main ones on the Auckland Harbour Bridge - all designed to keep traffic moving safely and as smoothly as possible on the city’s motorways.
Late in 2001 the ATMS system was enhanced with a series of new signals introduced to make it easier to advise motorists travelling on the Harbour Bridge of changing conditions ahead including queues, lane closures, accidents and lane changes.
These signals include:
- Sets of four flashing lights to indicate there is an accident ahead and traffic should proceed with caution.
- A recommended speed.
- An orange arrow indicating which traffic should move into the next lane.
- A red cross showing that a lane is closed.
The system continually measures traffic flows and traffic speeds at specific locations on the motorway system and compares them to normal expected traffic flows. When a change is detected, an alert is immediately sent to the ATTOMS Traffic Control Centre in Northcote. Here, based on pre-set plans, the system automatically responds to these changes and displays the appropriate signal/s to motorists. All of the suggested signals are verified by an operator before they are displayed on the motorway system.
In the latest enhancement of the system, speed signals and flashing lights will be used more frequently to advise motorists of queues, delays, incidents and accidents. While not mandatory, the speed signals are designed to keep traffic moving at a consistent speed, so avoiding stop starting, particularly during peak times.
When an accident occurs, the standard procedure is to close the minimum number of lanes, while ensuring traffic passes to one side of the accident, to allow access to emergency services.
“The new signals allow us to expand to full incident management,” says Transit Regional Manager Wayne McDonald. “They are part of a system that that is continually being developed to make using the motorway network safer, smoother and less frustrating for Auckland’s motorists.”