About Ramp Signals

How do ramp signals work?

Ramp signals operate according to traffic flow with electronic sensors, built into the road, detecting when traffic becomes heavy. A message is then sent via fibre optic cables to an automated server which immediately switches the ramp signals on. The server also adjusts the length of time between green lights as motorway traffic flows change.

The signals operate during peak hours in the morning and afternoon, as well as at any point during the day when traffic is heavy. Ramp signals are switched off again automatically when traffic is free flowing.

The system is remotely monitored and managed as part of operations at the ATTOMS traffic management centre in Northcote.

View a video of how ramp signals work.

Why do we need them?

Currently traffic on the motorway is disrupted by ‘bottlenecking'. This means whenever traffic enters the motorway and then shifts from lane to lane, it creates a slowing pattern as vehicles back up behind the on-ramp entry zone.

Most accidents on Auckland motorways happen during peak hours when traffic is stop-start, due to lapses in driver concentration and motorists travelling down crowded on-ramps vying for positions in traffic or trying to merge together.

Ramp signalling provides a smoother flow of traffic, minimising stop-start conditions by separating on-ramp traffic into streams of one or two vehicles. Ramp signals are designed to keep traffic flowing on the motorway and to reduce accidents.

With traffic on Auckland motorways growing, Transit is taking proactive steps to help reduce congestion by managing its existing motorways in the best way possible. Intelligent management is vital to sustaining and maintaining our motorways.

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Project Objectives

The ramp signalling and ATMS projects aim to:

  • Improve reliability of travel times on the Southern Motorway
  • Improve safety for users (e.g advance information about hazards)
  • Support integrated traffic management (e.g public transport initiatives)
  • Improve the travel efficiency for bus and freight transport (e.g provide priority access to bus/freight transport)
  • Improve information for motorists (e.g electronic message signs for road users)
  • Manage the effects of incidents on traffic (e.g improving warning systems when incidents occur)
  • Enable ongoing monitoring of ramp signalling system and ensure a responsive system (e.g real time monitoring of traffic management)
  • Ensure the system is sustainable in the long term

Working with Others

Ramp signalling is being launched by Transit New Zealand, working together with Auckland’s City, Regional and District Councils, Auckland Regional Transport Authority and Land Transport NZ.

Transit has been involved with these councils and agencies through ongoing consultation. It will continue to work alongside these organisations to ensure the smooth implementation of ramp signalling in each of Auckland’s major centres. 

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Benefits

By introducing ramp signalling to the Auckland motorway network, Transit will deliver the following benefits:

  • More consistent and predictable travel times
  • Safety merging
  • Fewer accidents
  • Better throughput of vehicles on the motorway
  • More consistent speeds

Ramp signalling is one of a number of initiatives being introduced by Transit to help deliver these benefits. The combination of these ideas is what is known as Travel Demand Management (TDM). Through its commitment to TDM, Transit aims to increase mobility by improving the efficiency of the motorway network and enabling people to make choices about how, when and where they choose to travel. 

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Outcomes

There are working examples of ramp signals in Auckland at Curran Street, Wellington Street and on the Northwestern to Northern motorways link through the Central Motorway (Spaghetti) Junction. Ramp signals are also operating on motorway on-ramps at Mangere, Papakura and Takanini.

Ramp signals at these locations followed on from an earlier trial at the SH20 Rimu Road on-ramp in 2003. The signals tested the technology and gave an indication of the benefits that ramp signalling could have if implemented across Auckland’s motorways.

Ramp signalling has been used for many years overseas as an integral part of comprehensive motorway management systems. The following statistics (averages) have been shown in similar projects in the United States and Europe, and are consistent with the expected outcomes in Auckland:

  •   9% - Increase in throughput of vehicles
  • 14% - Overall speed increase
  • 22% - Decrease in travel time
  • 24% - Reduction in crashes
  • 91% - Improvement in the reliability of journey times

More information about these outcomes in overseas studies can be found on the following websites:

 

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Priority Lanes

Transit is aiming to improve journey times and create a more free-flowing motorway with the opening of priority lanes on on-ramps.

The first trucks-only priority lane opened in October 2007, from the Grafton Rd southbound on-ramp to the Southern Motorway.

Priority lanes allow trucks to bypass the ramp signal without stopping and losing momentum, especially when on-ramps are on an incline. The faster access also means that trucks will be able to maintain a good speed onto the motorway, and will not slow down other vehicles.

The priority lanes will only be available to trucks when the ramp signals are switched on and operating. When the signals are switched off, trucks must use the normal on-ramp lanes to enter the motorway, as the priority lane reverts once more to an emergency access lane.

A total of 11 selected on-ramps across the Southern (SH1), Northern (SH1) and Northwestern (SH16) motorways will feature priority lanes for trucks and buses, with high occupancy vehicles (HOVs) being added at a later stage.

Priority lanes are also an outcome of the objectives detailed in the New Zealand Transport Strategy’s “Assisting Economic Development” section, by contributing to improving the flow of people, goods and services within and between cities in New Zealand.

View how truck priority lanes work.

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Auckland Ramp Signals

Transit is installing ramp signals on all 31 on-ramps across Auckland’s Southern Motorway and Central Motorway Junction (CMJ). Ramp signalling will be progressively extended across the motorway network on the Northern (SH1), Northwestern (SH16) and Southwestern (SH20) motorways.

The first phase of ramp signals has been introduced on the Southern Motorway and signals are established at:

Central Motorway Junction (December 2006)

  • Curran St (northbound)
  • Wellington St (northbound)
  • Northwest to North (SH16 – SH1) link & Port to North (SH16 – SH1) link (northbound)

Central Motorway Junction (October 2007)

  • Hobson St (southbound)
  • Symonds St (southbound)
  • Grafton Rd (southbound)
  • Khyber Pass Rd (southbound)
  • St Marks Rd (southbound)

 

Southern Motorway (October - December 2007)

  • Greenlane (southbound)
  • Ellerslie-Panmure (southbound)
  • Highbrook Drive (southbound)
  • Highbrook Drive (northbound)
  • Princes Street (southbound)
  • Princes Street (northbound)
  • Mt Wellington Highway (southbound)
  • East Tamaki (southbound)

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Advanced Traffic Management System (ATMS)

Ramp signalling was launched at the same time as an extension to a system called the Advanced Traffic Management System (ATMS). ATMS is made up of new gantries and advisory signs, which have been added to the Central Motorway Junction (CMJ). These electronic signs (like those on Auckland Harbour Bridge) show recommended speed limits, arrows directing traffic into other lanes and crosses indicating lane closures. Special cameras and electronic sensors in the road have been installed as part of this new traffic management system.

ATMS, along with ramp signalling, helps to manage congestion and improve safety on the motorway network.