Northlink WA - Southern Section

This double award-winning project by Main Roads WA achieved a 'Leading' As Built v1.2 IS Rating. 



NorthLink WA Southern Section will provide new interchanges on Tonkin Highway at Collier Road Drive, a flyover at Benara Road, and the upgrading of this length of Tonkin Highway.

Key construction works on the Southern Section include:

  • Upgrading Tonkin Highway to a six lane freeway between Guildford Road and Reid Highway.
  • Constructing a new interchange at Collier Road. Collier Road will be realigned and raised to go over Tonkin Highway, with on and off ramps connecting the two roads. This interchange will be similar to the ones at Tonkin Highway and Horrie Miller Drive, and Leach Highway and Abernethy Road.
  • Constructing a new interchange at Morley Drive. This includes a roundabout at ground level on Morley Drive that will connect with a raised Tonkin Highway. This will be the first interchange of this type to be built in WA.
  • A flyover at Benara Road over the Tonkin Highway.
  • New cycling and pedestrian facilities including a 4m wide shared path alongside Tonkin Highway.


  • Rating Type Road
  • Rating Score 95.2
  • Registered Date November 2015
  • Certification Date February 2019
  • Practical Completion December 2018
  • State WA
  • Suburb Perth
  • Capital Value $180 Million
  • Other Key Stakeholders 



Rating Highlights

For Design Rating:

First Leading Rating for Western Australia, under the ISCA (Infrastructure Sustainability Council of Australia) Rating Scheme

The score of 93 points is the highest WA score ever and the second highest ISCA rating score in Australia ever for a transport infrastructure project.

Sustainability was embedded in the Project Trademark and behaviours which were developed by the team as part of the partnering process with John Holland/Main Roads/Independent Certifier (APP).

John Holland held a Supply Chain Sustainability Day to raise awareness of sustainability expectations and opportunities among potential suppliers early in the project.

Pedestrian tunnel to Hampton Park Primary School minimises walking distance and has much improved visibility by using a 3-pin arch structure instead of a conventional design.

Innovation was demonstrated across several areas, achieved by cultivating a good working relationship with the Main Roads project team and specialists.

Costs and benefits have been calculated and show significant benefits from the sustainability initiatives included, both for construction costs and in operational savings over the life of the project.

21% decrease in materials lifecycle impacts. Lifecycle assessment in decision making: eTool life cycle assessment (LCA) model was used instead of the Materials Calculator. The tool was used early in detailed design to identify the highest impact materials so these could be prioritised.

10% RAP (reclaimed asphalt pavement) has been used throughout the project, and the team is working with suppliers and Main Roads to increase this to 25%. Although Main Roads encourages use of RAP, currently most projects in WA use no recycled asphalt and stockpiles continue to grow.

A trial of high modulus EME2 asphalt will be undertaken. EME2 is approximately 24% thinner, using less material than other formulations. EME2 is to be applied to a 700m section of the project in spring 2017. In addition to material reduction, EME2 is more tolerant of moisture than the traditional product, which should result in fewer rain delays and lower costs.

40% reduction in water use in construction and operation through a reduced delivery period and by designing out reticulated areas from the landscaping design.

9% reduction in energy use. Shared path light-dimming through the quietest hours of the night provides sufficient light for cyclists with 15% less energy overall.

Adaptive lighting trial for highway lighting – designed to achieve required light levels using 10% less energy, while increasing the life of luminaires by 50%. Importantly, it provides remote connectivity and fault correction which reduces cost and energy for maintenance, and can be retrofitted in other parts of the network if successful.

Community Benefits

Community priorities such as tree canopy cover, walking and cycling were recognised, and addressed.
A 4 metre-wide Principle Shared Path (PSP) will provide better connectivity across, and along the alignment (PSP width is usually 3 metres).

Pedestrian tunnel to Hampton Park Primary School minimises walking distance and has much improved visibility by using a 3-pin arch structure instead of a conventional design.


Australian Firsts

  • The use of life cycle assessment by a contractor in decision making during detailed design
  • Implemented a tightened asphalt specification to improve water resistance and durability to increase Pavement Design Life.
  • High modulus asphalt (EME2) trial on 700m section of the highway is the heaviest traffic loading section of a highway in Australia

Western Australia State Firsts

  • Grade-separated roundabout demonstrated to be the preferred solution with regard to congestion and road safety.
  • Adaptive lighting trial.
  • Dimming of PSP lighting for 50% of each night.
  • EME2 asphalt on trial section of freight route carriageway
  • Innovation: WA first grade separated round-about
  • Plans to use up to 25% recycled asphalt (RAP) content.
  • Design of pedestrian underpass using 3-pin arch structure.
  • Supplier Sustainability Day in collaboration with Supply Chain Sustainability School.
  • Principal Shared Path width increased to 4 metres for length of NorthLink WA.

Showcase Video




For more information on this project, visit the Main Roads WA website.