Decarbonising road transport: Designing low-carbon and green transport corridors
October 07, 2024
Decarbonising road transport with low-carbon design and creating green transport corridors can benefit communities
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Roads are essential for connecting our communities. But with an increased focus on decarbonising road transport, we need to start using more sustainable methods to design and build them.
At their simplest, roads are a way to get users from one point to another. But their impact is far greater. To date, efforts to reduce transport-related carbon emissions have been focused on electric and hybrid vehicle adoption. However, we can make great strides in the design and construction of our roads, long before the wheels hit the ground.
People, businesses, and governments are ever more aware of the impact of carbon emissions on climate change. The Australian Government aims to achieve net zero emissions by 2050. The Energy Council estimates almost 3 percent of Australia’s total emissions come from transport infrastructure. That means decarbonising road transport will be crucial to achieving net zero.
Every part of a transport corridor’s design affects carbon emissions, from layout and materials to construction methods and traffic management.
Every part of a transport corridor’s design affects carbon emissions, from layout and materials to construction methods and traffic management. Transport designers and engineers can help by looking at methods for decarbonising road transport at the beginning of each project. We need to move away from old approaches focused only on functionality and cost. It’s essential to embed carbon considerations and sustainability into every project.
Decarbonising road transport with carbon-sensitive design
Carbon-sensitive design involves planning and designing infrastructure to minimise an asset’s carbon footprint. This includes the construction stage, which uses materials and resources that emit carbon, and the operation stage, which looks at the carbon emissions of using and maintaining the asset. It also considers an asset’s end of life.
We need to focus on carbon from the start to the end of an asset’s life. That allows designers to reduce emissions at every stage of the design process and maximise the reduction of its carbon footprint.
We set and track sustainability goals by comparing usual designs with carbon-sensitive ones. This includes embodied carbon assessments, which capture greenhouse gas (GHG) emissions of construction materials. It also includes operational carbon assessments, which capture emissions during use. By comparing these, we can quantify the carbon reductions from our designs.
For our work on Transport for NSW’s wharves, we used its Carbon Estimate and Reporting Tool (CERT) to measure construction-related GHG emissions. We then reduced them by more than 10 percent. How? By replacing carbon-heavy materials such as steel and concrete with greener alternatives, helping the project meet its carbon-reduction goals. Contractors were also encouraged to further improve sustainability during construction, including using GreenPower for their site offices.
This helps designers and engineers make a case for sustainable design. And it also provides reports for government and road authorities working towards net zero targets.
A carbon-sensitive design approach also looks to the future. Transport corridors are designed with the end user in mind, so community feedback helps improve project design and end-user acceptance. It creates a legacy of sustainable infrastructure.
A carbon-sensitive design approach also considers the needs of the future.
Rethinking transport corridor design
Designers need to consider the carbon impact of every decision. While safety and compliance are crucial, the default approach may not always be the best.
Innovative solutions are emerging to make road projects more sustainable. This includes using recycled materials such as rubber, toner (ink cartridges), recycled glass, or plastic in asphalt pavements. It also includes using recycled concrete and building materials like clay bricks. Our team’s upgrade of Northbourne Avenue in Canberra was repaved using recycled asphalt. It was a more sustainable approach. And it was faster and more cost effective than traditional construction.
Even what seem like minor choices—the type of pavement used, the route chosen, or the design of intersections—can have a big impact. Each decision adds up. You can greatly reduce a project’s carbon footprint if you use recycled or recyclable materials and reduce the use of heavy machinery. Other key decisions include using precast units, reusing signs, allowing for smart traffic, incorporating nature-based solutions and design principles, and designing disassembly to reduce construction waste.
The Melbourne Airport Rail project is a great example of this in action. In line with Victoria’s Recycled First Policy, we prioritised the use of recycled and reused materials. This included more than 1,300 tonnes of recycled asphalt, 100 tonnes of recycled steel, and the use of crushed concrete. And it saved us from using 5,400 m³ in new material.
In the bigger picture, we can design for active transport modes. We should look at creating walkable and cyclable cities with shorter distances between amenities and public transport. Technology can play a role too. We should integrate smart mobility by integrating real-time traffic management systems into design.
In the future, low and zero-carbon concrete and steel could cut carbon emissions even more. Transport designers must keep their knowledge and skills up to date to challenge the status quo, set new standards, and bring clients along on the journey of decarbonising road transport.
Planning for better outcomes
A key part of carbon-sensitive design is looking at the entire life cycle of an asset. Planning for the long term from the start of the project will lead to better decision-making along the way.
Sustainability measures are often viewed as an extra cost. While they may sometimes come at a higher initial price, it’s important to look at the cost benefits over an asset’s lifetime. From smart traffic management systems to street lighting, sustainable projects often reduce maintenance and energy use. Research from the Global Center on Adaptation has shown that resilient infrastructure could deliver up to $12 for every $1 invested.
Research from the Global Center on Adaptation has shown that resilient infrastructure could deliver up to $12 for every $1 invested.
These savings can also extend into the end of an asset’s life when materials or asset components can be reused and recycled. Planning for this can help achieve a greater return on investment while minimising an asset’s carbon impact. In Australia, the Queensland Reconstruction Fund has shown a return of $3 for every $1 invested in resilient infrastructure over the past decade.
Implementing a framework for carbon management
When it comes to carbon emissions, no design decision is too small. So, it’s critical to integrate carbon-management principles into every stage of a project. But designers don’t have to go it alone.
The British Standards Institution (BSI) PAS 2080 is the leading standard for whole-life carbon management in buildings and infrastructure. Using this framework helps organisations and designers prioritise reducing carbon at every step of a project. The standard encourages a systems-thinking approach and promotes collaboration through the whole value chain. The aim is to reduce carbon and costs through intelligent planning, design, construction and use.
This common approach is important. That’s why our team’s UK Water business has achieved PAS 2080 certification from BSI. It’s also why we’re implementing PAS 2080 principles across all sectors and regions. We’ve also been part of the industry working group that supports the development of the 2023 update to PAS 2080.
Our road projects are part of an ecosystem that fosters safer and vibrant communities, sustainable practices, and long-term resilience.
Decarbonising road transport for a greener future
A carbon-sensitive approach allows designers to look past the traditional view of road corridors as mere transportation arteries. Instead, it envisions green transport corridors as living, dynamic assets that are built to improve our well-being.
We’re already taking a carbon-sensitive approach to our road projects. How so? By including natural elements into the design, which offers benefits like flood protection and biodiversity enhancement. We’re also designing for the future. We’re creating elements like bridges and stations with disassembly and reuse in mind.
In Queensland, we’re pursuing an infrastructure sustainability rating for our Beams Road project. Our design team has included sustainability measures throughout the project’s planning and design phase. It includes carrying out a Climate Change Risk Assessment and reviewing energy use and GHG emissions over the project’s life cycle. By comparing the initial design with the final one, we found the project will cut carbon emissions by more than 10 percent. We’re using monthly reports to keep track of the project’s sustainability efforts.
Our road projects are part of an ecosystem that fosters safer and vibrant communities, sustainable practices, and long-term resilience. This helps build a better future. We need to prioritise decarbonising road transport. When we do, we can redefine the future of road transport to create infrastructure that supports the people who rely on it daily.