Managing the Environment


Protect and enhance the environment, including heritage, and social values in all our activities, products, and services.


  • Recognise the importance of environmental, social and heritage values and the broader benefits of these for the community
  • Foster strategic relationships with community and other stakeholders to contribute to the management of environmental values
  • Have strong environmental governance of our activities and deliver broad community benefit through including environmental requirements in planning, programming, constructing, and maintaining practices
  • Communicate our environmental policy and environmental performance publicly

Target 100%

Audits of compliance with state-wide clearing permit completed


Target 100%

Audits of compliance of Environmental Protection and Biodiversity Conversation Act approvals completed


Target 90%

Manage all environmental incidents within required timeframes


Target 100%

Deliver training on environment topics to four of our regions


Target 90%

Performance in environmental management is within target

Looking Ahead

Projects and activities planned for next financial year, some of which have already commenced:

  • Obtaining environmental and heritage approvals for projects in accordance with time frames and ensuring compliance with approval conditions.
  • Imbedding our environmental and heritage processes in the new in-house maintenance delivery model
  • Developing and rolling out specifications and associated guidance material for use of Dieback Eradication Treated Road Building Materials
  • Contributing to the Commonwealth Department of Climate Change, Energy, the Environment and Water’s Nature Positive Plan: better for the environment, better for business and imbedding the necessary changes within our environmental and heritage processes
  • Continuing to deliver the Wheatbelt Revegetation Bank program
  • Contributing to Main Roads’ Transition Plan towards Net Zero Emissions

Sustainability Assessment in Projects and Operations

Recognising the importance and potential for the greatest impact and value from our major projects we have adopted the Infrastructure Sustainability (IS) rating tool, Australia’s only comprehensive rating system for evaluating sustainability of infrastructure.

All infrastructure projects exceeding $20 million utilise the IS framework as part of project development and evaluation, and all projects valued at more than $100 million are registered with the Infrastructure Sustainability Council (ISC) for assessment. We currently have 19 projects registered. We have a corporate commitment that our planning projects must achieve at least a Bronze rating, while our construction projects must achieve a Silver rating for both the design and as-built phases. During the year projects achieving IS Ratings included:

  • Tonkin Gap – Gold Design Rating
  • Mitchell Freeway Extension Hester to Romeo – Silver Design Rating
  • Eastlink Work Package 1 – Silver Planning Rating
  • Mandurah Bridge Duplication – Bronze Planning Rating

Stand-alone public reports are produced for our projects with sustainability obligations. This year, reports have been submitted and are accessible from our online report for the following projects:

  • Albany Ring Road
  • Bunbury Outer Ring Road
  • Causeway Pedestrian and Cyclist Bridges
  • Great Eastern Highway Bypass Interchange
  • Mitchell Freeway Extension Hester to Romeo
  • Leach Highway Welshpool Road Interchange
  • Smart Freeways Mitchell Southbound Hester to Warwick
  • Smart Freeways Mitchell Southbound Reid to Vincent
  • Stephenson Avenue Extension
  • Thomas Road over Rail
  • Tonkin Gap Project

Infrastructure Sustainability Council Awards

The ISC Annual Gala Awards recognise and reward individuals, assets and organisations leading the way in advancing infrastructure sustainability across the Australian and New Zealand sectors. We were recognised and received an outstanding result by winning the following award categories.

  • Industry Impact (Public Sector) – the submission focused on Main Roads approach to Aboriginal Engagement and Participation and our efforts for the circular economy for crushed recycled concrete and crumb rubber
  • Outstanding Achievement Planning (ISv2.0) – Bunbury Outer Ring Road – being the first project to achieve a planning rating
  • Outstanding Achievement Design (ISv2.0 and IS2.1) – Armadale Road to North Lake Road Bridge Project
  • In addition, ISC recognised the pioneering commitment of Main Roads in transitioning to ISv2.0 and IS2.1 across project development and delivery

Environment and Heritage Management

We use the precautionary principle in our approach to environment and heritage management and avoid and minimise impacts wherever possible. To achieve this, we ensure that all our activities are initially screened for potential environmental and heritage impacts.

Those activities that potentially have a risk of adverse impacts are subject to further investigations while projects that have a low environmental or heritage risk are managed using our standard environmental and heritage practices.

Last year, we screened a total of 1,017 activities with almost 30 per cent of these activities requiring further investigations, such as field inspections, biological surveys, archaeological or ethnographical investigations, or consultation with stakeholders and regulators, to ensure appropriate environmental management was applied.

Once all investigations and assessments are completed, we consult with our road planners, designers, and engineers to identify opportunities to avoid and then minimise all potential adverse environmental and heritage impacts. This is often achieved through one or more of the following.

  • Analysis of scope and design options
  • Road re-alignment
  • Re-locating signs, crossovers or, parking bays to areas with lower environmental values
  • Modifications to the road design.

Where environmental and heritage impacts are unavoidable, we ensure we comply with State and Commonwealth environmental and heritage legislation. We referred some activities with potentially significant impacts to the relevant regulatory authorities for assessment and approval. This is a summary of our applications for approvals over the past three years.

Applications for Approval 2020 2021 2022
Aboriginal Heritage approval sought 1 29 28 25
Aboriginal Heritage approval granted 1 26 27 24
Historic Heritage approval granted 2 - 5 5
Project specific clearing permit applications 11 7 5
Project specific clearing permits granted 7 5 2
Projects assessed using Main Roads state-wide clearing permit 118 98 107
Projects referred to the WA Environmental Protection Authority (EPA) under Part IV of the Environmental Protection (EP) Act 5 1 1
Projects approved by the WA Minister for the Environment under Part IV of the Environmental Protection (EP) Act 1 0 1
No. of projects referred to the Commonwealth DCCEEW under the Environment Protection and Biodiversity Conservation Act (EPBC Act) 7 1 3
No. of projects approved under the EPBC Act 3 7 1
NOTE: all approvals granted may include applications made in previous years.
  1. This includes Regulation 10 and Section 18 applications under the WA Aboriginal Heritage Regulations 1974 or WA Aboriginal Heritage Act 1972 (respectively) submitted or granted between 1st January to 31st December 2022.
  2. This includes Government Heritage Property Disposal Process approvals and any other type of formal approval from the Heritage Council of WA.

In the 2022 calendar year, we applied for a total of 25 Aboriginal heritage approvals and five project-specific clearing permits. A total of 107 projects were assessed under our State-wide clearing permit CPS 818 in 2022, with four projects submitted to the Department of Water and Environmental Regulation (DWER) for approval in accordance with the conditions of the State-wide clearing permit CPS 818.

In addition, one project was considered to have potentially significant impacts and was referred to the WA Environmental Protection Authority (EPA) for assessment. Three projects were considered to have potentially significant impacts to Matters of National Environmental Significant (Matters of NES) and were referred to the Department of Climate Change, Energy, the Environment & Water (DCCEEW) for assessment under the Environment Protection and Biodiversity Conservation Act (EPBC Act). Four projects referred to the EPA were still under assessment at the close of 2022. One project was approved by the WA Minister for the Environment in 2022. Three projects referred to the DCCEEW were still under assessment at the close of 2022. One project was approved under the EPBC Act in 2022.

Clearing Native Vegetation

We strive to find a balance between achieving road safety objectives and the environment however, it’s not always possible to avoid clearing of native vegetation. When this is unavoidable and if it’s significant, we offset the impacts of the clearing. This may be through revegetation by seeding or planting, purchasing land to add to the Conservation Estate or providing a monetary contribution to the Western Australian Environmental Offset Fund for the acquisition of land and addition to the Conservation Estate
(Ref and

The tables below summarise our clearing, revegetation, and offset activities over the past three years. The amount of clearing in 2020, 2021 and 2022 calendar years includes clearing authorised under Main Roads State-wide clearing permit CPS 818, project-specific clearing permits, clearing undertaken under approval from the Western Australian Minister for the Environment under Part IV of the Environmental Protection Act (EP Act), as well as clearing of non-native vegetation authorised under the EPBC Act.

Clearing of native vegetation undertaken in 2022 under our State-wide clearing permit CPS 818 is available on our website.

Clearing 2020 2021 2022
Total area cleared (ha) 210 631 419
Revegetation (ha) (a) 0 0 27
Land acquisition (ha) (b) 204 108 536
(Value of land acquired ($)) ($) 1,528,091 1,214,683 1,617,000
Financial contribution ($) 629,976 71,519 790,569
Area of land to be acquired using the financial contribution (ha) (c) (368) (32) (166)
Total area offset (ha) (a+b+c) 572 140 729
Revegetation undertaken by Main Roads not required as a condition of approval (offset)
Total revegetation* (ha) 214 96 146
* Revegetation related to the Wheatbelt Revegetation Bank is not included in the total revegetation figures. (See Wheatbelt Revegetation Bank below.)

Last year, we cleared 419 hectares of vegetation for the delivery of 94 projects. We provided offsets in the form of land acquisition and monetary contributions to the Western Australian Environmental Offsets Fund for the purchase and management of a total of 536 hectares of native vegetation. We also undertook 173 hectares of revegetation works, of which 146 hectares were not required under a legislative approval and the revegetation was initiated by Main Roads.

Wheatbelt Revegetation Bank

The Wheatbelt Revegetation Bank is our initiative offering a sustainable solution to the often-conflicting needs of improving road safety and conserving roadside vegetation. Several upgrades are planned over coming years to improve road safety across the Wheatbelt road network. Environmental offsets typically involve the purchase and protection of remnant vegetation on freehold land which is becoming challenging as the availability of land with quality remnant vegetation is limited and declining. In addition, purchasing and protecting existing vegetation does not necessarily replace the vegetation that is removed for road upgrades.

The project offers a sustainable approach to providing environmental offsets as well as addressing the incremental loss of native vegetation. It involves the purchase and revegetation of cleared farmland abutting road reserves or existing areas of high-value remnant vegetation. The program aims to establish, within a period of ten years, native vegetation that meets the criteria for the Eucalypt Woodlands of the Western Australian Wheatbelt Threatened Ecological Community. Once established, these revegetated areas will form an offsets ‘bank’ that will simplify and expedite environmental approvals for future road upgrade programs across the Wheatbelt.

The area undergoing revegetation in 2022 was relatively small, at 10 hectares, because of a lack of suitable new sites, and limited availability of native seed collected in proximity to the revegetation site. Work to identify and purchase land for addition to the Wheatbelt Revegetation Bank has commenced. A ramp-up in the area undergoing revegetation is expected from 2023. As of the end of the 2022 calendar year, no portion of the Wheatbelt Revegetation Bank has been utilised as an offset for any of our projects.


We aim to undertake all our activities in accordance with our procedures though we have systems and processes ready to adequately respond to environmental incidents where this does not occur. An environmental incident is any activity that has the potential to have an adverse environmental impact. The activity may include those undertaken by us or our contractors, or a third party not employed by or working on behalf of our organisation. This table outlines significant incidents that have occurred over the past three years. Significant incidents are those with a moderate, major, or catastrophic consequence.

Significant Incidents
(Moderate, Major and Catastrophic)
2020 2021 2022
Incidents caused by Main Roads 9 12 20
Incidents caused by third parties 5 11 9
Insignificant and minor incidents have not been reported here.

There were no catastrophic or major incidents in 2022; however, there were 29 moderate incidents, with 20 caused by our activities and nine caused by Third Party activities. These incidents related to:

  • 12 incidents of unauthorised clearing of native vegetation, including two by a third party
  • 8 spills including seven by a third party
  • 5 administrative non-compliances with approval conditions
  • 1 impact to Aboriginal Heritage
  • 1 impact to fauna
  • 1 incident of erosion and sedimentation
  • 1 not following internal processes

Of the 12 incidents of unauthorised clearing, 10 related to incidents by us that resulted in a total of 11.55 hectares of unauthorised clearing of native vegetation and two third party incidents that resulted in a total of 0.40 hectares of unauthorised clearing of native vegetation.

Incidents were reported to the relevant authorities and there were no penalties or financial sanctions related to any of these incidents. We have addressed these procedural failures through training, changes in processes and increased compliance audits to ensure they are not repeated.

Urban Air Quality

Air quality in Perth is generally high when compared to both Australian and international urban centres. The reduction in pollutant levels can be attributed to tightening of national vehicle emission and fuel standards and the management of industrial and domestic air pollution. Initiatives that contribute to the reduction of emissions include:

  • Encouraging active transport and alternative forms of transport
  • Optimising traffic management on our network enhancing traffic flow
  • Options for further integrating roads, rail crossings, mass transit and future technologies
  • Uptake of low emissions technology vehicles that generate less pollutants
  • Strategies that reduce congestion and improve network efficiency.

Using the Australian Transport Assessment and Planning Guidelines 2016, we have used internal data to estimate emissions trends of the six main air pollutants (carbon monoxide, nitrogen dioxide, photochemical oxidants (as ozone), sulphur dioxide, lead and particles) from operations and congestion on state and significant local roads in the metropolitan area. A complete breakdown of emissions by type is available in the Additional Environmental and Sustainability Disclosures section.

Net Zero Transition

Following the release of the Western Australian Climate Policy we are developing a Net Zero Transition Plan which will guide actions in support of the state’s aspiration to achieve net zero greenhouse emissions by 2050. The plan will focus on our operations and infrastructure investments and consider impacts from the use of the road network. This new plan will replace our existing Carbon Reduction Plan and Target and prepare us for imminent introduction of climate legislation which will establish the State’s long-term target of net zero emission by 2050 and provide statutory requirements to set interim emission reduction targets.

Total emissions across our facilities over the past year were 22,008 tCO2-e, which is below our target of 23,442 tCO2-e. The table below shows our greenhouse gas emissions (Scope 1 and 2) over the past three years. Detailed information showing data over the last three years by Scope, Source and Intensity are available in the Additional Environmental and Sustainability Disclosures section of this report.

Scope 1 and 2 2021 2022 2023
Greenhouse gas type (t CO2) 27,313 24,052 22,008

Western Australia’s Electric Vehicle Strategy

The State Electric Vehicle Strategy is linked to the State’s Climate Policy as electrification of transport is pivotal to reducing emissions from transport. We are committed to increasing the uptake of electric vehicles within our own light and heavy vehicles fleet and supporting the state government target of 25 per cent, of all new light and small passenger, and small and medium SUV government fleet vehicles, to be electric by 2026. We are also committed to leveraging our project investments to increase the uptake of electric vehicles within project supply chains. Additionally, we are assisting Synergy and Horizon to find suitable locations for the Western Australian electric vehicle charging network in remote locations.

Climate Change Adaptation

To meet our obligations under the WA Climate Policy, we are revisiting our assessments of the vulnerability of the state road network to broader impacts from climate change. We have already identified more than 52 kilometres of State roads assessed as warranting more detailed evaluation for the impacts of sea level rise. The indicative replacement value of this at-risk infrastructure is approximately $446 million. An evaluation method to help facilitate a network-wide vulnerability assessment has been piloted which will build capacity for routine vulnerability assessments. To supplement this work, we are establishing a baseline identification of vulnerability within each region, which will inform our further network investments.

Materials for Road Building

In support of our Waste Avoidance and Resource Recovery Strategy 2030, we incorporate recycled content into the significant materials used for road construction. Crushed recycled concrete (CRC) makes up 50 per cent of the state’s waste stream and in line with the Waste Authority’s Roads to Reuse Program we remain committed to use CRC when appropriate on our major projects. A total of 49,191 tonnes of CRC was used over the past 12 months which takes our cumulative total to 192,572 tonnes.

Waste tyres are another significant environmental challenge for Western Australia and to maintain a local tyre recycling industry we mandate the use of Tyre Stewardship Australia endorsed crumbed rubber in resealing works to incentivise local sources using recycled tyres. We also continue to develop and implement alternative crumbed scrap rubber bituminous binders, including binders that may be appealing for local governments to use. During the past year, we successfully used 3,028 tonnes of crumbed rubber bituminous binders on our projects and maintenance works.

Other materials that we are seeking to use more of include Fly Ash within concrete mixes, recycled plastic, and Food Organic and Garden Organic (FOGO) waste as soil conditioner. During the year we successfully used approximately 120 cubic metres of FOGO and installed recycled plastic drainpipes on our major projects.

Detailed information and data from the past three years is available in the Additional Environmental and Sustainability Disclosures section and covers the following categories:

  • Imported road construction material by type
  • Imported recycled construction material by type
  • Waste material to landfill by type
  • Materials recycled by type.