The Western Distributor design is being developed through the planning and tender process. This involves identifying, assessing and refining different design options to develop a final design in preparation for construction.

Specialist engineers and architects will design the roads, tunnels and structures that form the Western Distributor. To do this they draw on a range of inputs to achieve the best possible outcomes for the community, road users and the transport network.

Designs are assessed using criteria that consider traffic, urban design, environment, cost and stakeholder and community feedback.

Design development process

Design development is a structured process. Designs are constantly reviewed,evaluated and tested against new information and feedback to refine and reach the best solution.

Six stage design process: identify the need, identify the constraints, develop possible solutions then iterate through assess possible solutions, test and get feedback, refine

Design development iterative process

What are functional requirements?

Functional requirements are the criteria that tenderers must use to develop their tender response. If the tenderer does not meet all the requirements, their bid may not be accepted.

The functional requirements cover a range of topics including road design, quality of construction, traffic management, operational safety, ongoing maintenance, regulatory compliance, sustainability, urban design and land availability amongst others.

Some requirements are very strict while others provide flexibility to encourage innovative thinking to achieve a specified outcome.

What is a Reference design?

The Reference design is a base for tenderers, upon which they can develop their tender response.

The Reference design meets the project’s functional requirements and helps explain them in a visual way. It’s a way for the project team to demonstrate that the functional requirements are achievable.

The Reference design has been developed taking into account the project objectives, technical requirements, environmental constraints and feedback from stakeholders and the community.

Tenderers are encouraged to use their specialist knowledge and expertise to identify solutions that enhance the design to achieve a better outcome.

As a result, tenderers may produce a similar design or suggest an improved design in one or more areas to address a certain challenge or add benefit.

How did we get to a Reference design?

In the course of developing the Concept and then the Reference design, many different ideas have been discussed, tested and either discounted or developed further. This includes comparing the pros and cons of different options, reviewing stakeholder and community feedback and further testing the designs against technical requirements and land use constraints.

Key design considerations

The project design is influenced by a range of considerations, including:

  • road design standards and guidelines
  • safety requirements for road usersand surrounding communities
  • required connections and integration with the existing road network
  • durability and life-cycle requirements
  • forecast traffic volumes
  • land availability
  • integration with existing and future land uses
  • protecting significant heritage, ecological and environmental assets
  • relevant legislation for planning and infrastructure
  • management and maintenance of the road in the future, including safe access for maintenance
  • constraints and locations of existing utilities such as power lines and underground sewers
  • achieving value for money
  • ground conditions, including any need to contain or remediate contaminated land or groundwater
  • constructability or the ability to build the proposed roads, bridges and tunnels in the most effective way
  • likelihood and impact of flooding
  • the need to future-proof to ensure existing and future needs can be met.

What's important in design

There are a number of other factors that are taken into account during the design process.

These factors influence the criteria used to evaluate design options and include:

  • stakeholder and community feedback
  • urban design and sustainability aspirations
  • likelydriver behaviour
  • existing and future land use.

The tenderer’s role in design development

The tender process is interactive, allowing regular communication between tenderers and the project team. Tenderers can ask questions, request feedback and test their thinking as they work on their design and construction proposals.

The project team will also regularly share new information with tenderers, including feedback received through the Community Liaison Group and other engagement forums.

Environment Effects Statement

A comprehensive and transparent planning, consultation and approvals process for the Western Distributor through an Environment Effects Statement (EES) has commenced.

An EES provides a.comprehensive framework for assessing the effect of major projects in Victoria and informs the planning approval decisions that are required from authorities.

The EES will be publicly exhibited in the first half of 2017 with construction on the project expected to begin in late 2017 and complete in 2022.

More information about the EES process is available from the Department of Environment, Water, Land and Planning. Information about what will be in the EES for the Western Distributor can be found in EES Specialist Studies.


Timeline showing the key steps in the design development process.

Project timelines

Next steps

  • tenderers bid to design and construct the Western Distributor using the Reference design and functional requirements as a guide
  • specialists commence impact assessments for the EES using the Reference design
  • engagement continues with stakeholders and the community
  • tenderers submit their response to the project team
  • EES is updated to include changes to the Reference design
  • EES is released for consultation in early 2017

Download the Design development discussion paper (PDF 778kb)

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