In a joint venture with Jacobs, Arup was engaged as the designer for the Fulton Hogan Seymour Whyte Joint Venture (FHSW JV) to construct the Bruce Highway Upgrade – Caloundra Road to Sunshine Motorway (CR2SM) on behalf of Department of Transport and Main Roads (TMR). The project team developed an innovative design solution that transformed the Caloundra Road interchange into a Diverging Diamond Interchange (DDI) – the first built in Australia.
A DDI is a type of diamond interchange. Like roundabouts, DDIs tackle the conventional intersection conflict points that cause congestion, delays and crashes by removing or conveying the traffic differently, resulting in profound traffic performance and safety improvements. Compared to the equivalent conventional upgrades, these treatments can generally provide up to 50% more traffic efficiency and over time are significantly safer due to removing the severe crossing points at the intersections.
The CR2SM project is a great example of innovating for impact, using fresh thinking to consider the environmental, social, and economic implications and how we can do things differently.
1st Diverging Diamond Interchange in Australia
29haof forest preserved
130,000m³of material reused
Planting the seeds of innovative design
Our team first presented the DDI concept ten years ago for another high-profile TMR project in South East Queensland. While the concept wasn’t the right fit, it planted the seed for this innovation. It showed TMR we wanted to push the boundaries and challenge the status quo of road design in Australia. So, when the Bruce Highway Upgrade – Caloundra Road to Sunshine Motorway project came up, we knew it was the perfect opportunity and time to put this innovation back on the table.
Innovation like this doesn’t happen overnight. It takes conviction, trusted partners like The Department of Transport and Main Roads. ”Alex Borg Principal | Highways – Australasia Leader, Arup
Bringing DDI design to Australia
Through the global Arup skills network, our San Francisco team introduced our Queensland team to Gilbert Chlewicki, based in Washington DC, who is recognised for creating the DDI concept and the driving force behind this ground-breaking design across the United States. Arup invited Gilbert for a speaking tour across Australia, talking to state government highway organisations on the concept and success stories from the 60 plus interchanges already built at that time in the United States.
During this tour across Australia, we paid particular attention to Queensland and TMR, where knowledge of the DDI concept existed, and we had a trusted relationship. We explained that while the innovation might seem risky, this approach introduced new ideas in a tempered way using previous examples and experience from the United States. Not long after this engagement, we were appointed to the project and visited the United States to see the new concept in action and develop a detailed understanding of the DDI design, construction and operational aspects. TMR was a collaborative partner in developing final design, working alongside Arup and Jacobs, contributing to a growing field of knowledge for the design and increasing knowledge of DDIs across Australia.
As a result, we were appointed to the project and visited the United States to see the new concept in action and develop a detailed understanding of the DDI design, construction and operational aspects.
TMR was a collaborative partner in developing final design, working alongside Arup and Jacobs, contributing to a growing field of knowledge for the design and ultimate delivery of DDIs in Australia.
Making a positive impact on the Sunshine Coast
The Bruce Highway Upgrade – Caloundra Road to Sunshine Motorway opened in December 2020, and already we are seeing the impact the design is making. Choosing this design led to the reuse of 130,000m³ of material and a 29-hectare footprint reduction on the Mooloolah River National Park (former Beerwah State Forest), conserving this environmental and culturally significant space for the future. The design has proved safer, reducing traffic incidents and travel time through the interchange. In addition, the new highway provides active transport infrastructure for cyclists, pedestrians, new carpool and bus stop facilities.
Transforming road design in Australia
TMR has now adopted the DDI methodology for more interchange sites across South East Queensland. This project helped develop new Australian road design guidelines to inform future implementations of the DDI in Queensland and shared more broadly across Australia.