The challenge of designing sustainable roads lies in the multitude of factors that need to be considered and overcome. One of the crucial aspects is the selection of construction materials, as they play a vital role in the sustainability of roads. After all, a road is essentially composed of layers of construction materials. The availability of local resources greatly influences the sourcing process. And in the end the choice of materials significantly impacts the road's sustainability, contributing to 85% of the carbon footprint and 60% of the overall costs (ORIS estimates).

So, what levers should you consider?

1. Carbon footprint: Limit the Global Warming Potential

Not surprisingly, reducing carbon emissions is the first factor that comes to mind when considering sustainability. The first challenge is to accurately measure the impact over the entire lifecycle of a road project. Some materials may have a lower carbon footprint during production but may not last as long as others, resulting in earlier repairs and ultimately a higher overall carbon footprint. It is also important to consider the impact of traffic patterns and local weather conditions, as these factors affect the durability of materials used for the road.

To overcome these challenges, advanced algorithms and Artificial Intelligence can be used to analyze multiple design and sourcing options, to iterate towards the most appropriate design. Digital tools like ORIS make this process much faster, taking only a few days instead of a couple of months. And enable to reduce the carbon footprint by up to 50%.

2. Circularity: Reduce the use of raw materials with recycled materials

Using local materials, particularly those that are recycled, is essential when designing sustainable roads. The identification and utilization of local recycled materials, such as temporary excavation materials from a large project, greatly contribute to the overall sustainability of a road.

By referencing all available sources of materials close to your project, ORIS enables the optimization of materials, resulting in a reduction of primary materials consumption by up to 80%. This not only promotes sustainability but also supports efficiency in road construction. 

3. Resilience: mitigate the effects of climate change to ensure longevity of the road

One crucial aspect of ensuring the longevity of roads is to make them resistant to extreme weather events. While reducing emissions is a primary focus (as mentioned in point 1), it is also vital to anticipate the effects of climate change on the local site. Factors such as heavy rains, landslides, and high temperature variations can all impact the durability of the road.

To address this, using digital twins to replicate the road design in its real environment and input data from climate change effect supports anticipation of what needs to be considered when choosing construction materials. This proactive approach during the design phase can go a long way in ensuring the road's resilience. The ORIS team can provide support with this process.

4. Budget: Control costs

Sustainability should not come at unbearable costs. By using digital tools like ORIS, you can identify alternative design options that maintain control of the budget, with the potential to reduce it by 15% to 30%.

How is this possible? Favoring local sources and recycled materials helps to keep budget costs in check. When materials are closer to the project site, transportation and associated costs, such as fuel, are minimized.

5. Road safety: Make sure it's safe for every user

The final element to consider revolves around the end-user and falls under the social aspect of sustainability: road safety. It is imperative to design a road that prioritizes the safety of all individuals, including cyclists and pedestrians. ORIS utilizes the iRAP Star Rating in its simulations and models, which serves as an objective measure of safety. This rating takes into account over 50 road attributes that impact the risk for vehicle occupants, motorcyclists, cyclists, and pedestrians.

By implementing this approach, road designers can incorporate the best safety features, ensuring that the road meets the highest level of safety right from its inception.

By considering all of these factors and using advanced technologies, we can design roads that not only consider all aspects of sustainability but are also cost-effective and safe to use. The integration of these factors and technologies allows for a holistic approach to road design, ensuring that all aspects of sustainability are taken into account.