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Project introduction

Working with Auckland's local and regional councils, and AT has seen the installation of 61 ramp signals on the southern, northern and northwestern motorways as part of a comprehensive motorway management system which is now completed. Another 33 are planned for the Western Ring Route.

  • Estimated project dates

    Aug 2006–Oct 2009
  • Estimated project cost

    $20 million to $100 million
  • Project type

    Road management
  • Project status



Ramp signals are traffic signals at on-ramps that manage the rate at which vehicles move down the ramp and onto the motorway. Ramp signals operate only when needed during busy periods. Ramp signals improve traffic flows and safety on the motorway, while enabling more consistent speeds, safer merging and more predictable travel times. The system is designed to achieve the best possible throughput and efficiency while ensuring minimum overall delay for all motorists.


  • More consistent and predictable travel times.
  • Safer merging.
  • Fewer accidents.
  • Better throughput of vehicles on the motorway.
  • More consistent speeds.
  • A total of 14 selected on-ramps feature managed priority lanes for trucks, buses and carpool vehicles, as well as specific truck priority and bus priority lanes.
  • 2000 detectors are located beneath the road surface to monitor and manage traffic volumes both at the on-ramp and along the local roads.
  • 600 electronic signs are used to inform drivers of the ramp signal operations and traveller information.
  • Traffic detectors measure when queues are building and change the signal phasing to speed up traffic through the on-ramp.
  • Operators have a range of over 100 cameras giving a continuous view of traffic operations in the area.
  • Close coordination with Papakura District, Auckland, North Shore, Manukau and Waitakere City Councils manages and assists traffic flows on the local approaches to the on-ramps.
  • Physical work includes bringing the existing ramps up to full modern geometric standards together with improvements to a number of the existing off-ramps.

The measured results show that with the ramp signals operating, there is an overall 15% improvement in travel speeds and a 5-15% increase in the rate of vehicles flowing on the motorway.