Illustration of intersection; Illustration of intersection;

The next-generation intersection: a smart new tool that gives us hope

It is said that you can’t expect to do the same thing over and over again and expect a different result. Never has a truer word been said, especially in relation to road design in our cities right now. Our approach to road design is changing, as it should, as our cities themselves change.

Thankfully, there is a shiny new tool in our road design toolbox that is enabling us to create smarter roads – safer, more efficient, reliable, streamlined roads, at less cost and with more amenity for all road users – pedestrians, cyclists, skateboarders and all!  It’s called a CFI – a continuous flow intersection – and we have designed two, one at Hoddle Street in Melbourne and most recently, one in Sydney. Let’s look briefly at how our cities are changing, what this means for our roads and why I think new tools like CFI’s are likely to become more common

Traffic in Sydney Traffic in Sydney

Population growth and expectations

The latest ABS city projections has Melbourne and Sydney reaching 11m people by century’s end. Clearly, the trend towards urban living is expected to continue. With population growth comes increased densification – of housing, of schools, of hospitals, of cars… Yes, cars.

Although we are seeing some societal shift towards moving away from the car, it is not a simple either/or decision – public transport or private car. People make different mode choices based on different needs at different times of the day. We also simply expect choice.

There is a growing maturity in expectation of good design within Australia. I think that people now simply expect ‘better’. More is expected of us as designers and of our civic leaders, and rightly so. Communities and residents want the right solution with minimal negative impact – be this residential, commercial, environmental, or other.

It is time for us to design better roads that provide better options for all modes of transport.

I have spent the last 17 months redesigning roads right on my own doorstep, which has been an illuminating journey.

The Alexandria to Moore Park corridor is in the process of a complete redesign. It’s a critical urban arterial route connecting the inner west to the eastern suburbs allowing people to avoid the Sydney CBD. It also happens to be at the heart of one of the city’s fastest growing precincts. We are about to see densification along this corridor, unlike we have seen before in Australia.

There are several urban renewal projects planned alongside with 45,000 more people expected to live within this corridor over the next 15 years. And with WestConnex also feeding in from the west, by 2021 traffic volumes are projected to grow by 50% or more in peak periods along this corridor.

Bruce Highway – Caloundra Road to Sunshine Motorway

Aerial view of Bruce Highway before construction

We developed an innovative design solution that transforms the Caloundra Road interchange into a Diverging Diamond Interchange (DDI), the first to be built in Australia.

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Streamlining Hoddle Street

Hoddle Street in Melbourne

A high profile study within Victoria as well as Australia, the Hoddle Street-Punt Road corridor is arguably the most important arterial road in inner Melbourne.

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Alexandria to Moore Park

Illustration of car going in the right lane

As part of the Alexandria to Moore Park Connectivity Upgrade in Sydney, we have created a design that will improve the experience for people travelling by a variety of modes.

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As for the particular intersection where I got stuck with my daughter – the corner of Anzac Parade, Alison Road and Dacey Avenue, myself and my colleagues have thrown out the old rule book of road design and started anew. With Roads and Maritime Services, we are venturing in to new territory creating the concept design for the first CFI in NSW.

This is not innovation for innovation’s sake. For me, innovation is only useful if it solves a problem other conventional solutions can’t, and this is certainly the case here. ”

Claire Moore Australasian Flooding Skills Leader

For the geeks out there, like me, here’s how it works. Common in the US, but new to Australia, CFI’s are a really smart solution to improve the performance of intersections with a high right-turn demand, as tends to be common in urban environments. In simple terms, this ‘at grade’ innovative intersection allows right turn movements to occur at the same time as through movements in both directions. 

The next generation intersection

We modelled numerous options and none of them created the performance outcomes required – for cars, pedestrians, cyclists or for users of the new CBD and South East light rail due to commence services in 2019.

Our design of this CFI was the only option that ticked all boxes for all modes of transport. Average waiting time for vehicles at this intersection will be reduced by a third. This is during peak am traffic and with priority given to the new light rail vehicles travelling through!

I’ve been at all the community consultations and I do understand a lot of the concerns, but I can say – as an engineer and local resident – that this is by far the best outcome for all modes of transport. ”

Claire Moore Australasian Flooding Skills Leader

Ultimately, I think these CFI’s, in Sydney and at Hoddle Street in Melbourne, are just the start. Their slimline footprint, if nothing else, will appeal, as cities increasingly find themselves with so many competing constraints. Space is one. As is the cost of that space. With land values so high, conventional approaches to improving existing or creating new intersections will not be viable. Our designs need to do more with less.

They will become less extraordinary, and more ordinary as our cities, and expectations of great design, grow. I wonder where else in Australia a CFI could bring hope for a smarter future for its citizens?