BRIDGING TUNNELS AND DESIGN: AUSTRALIA’S SYMPHONY OF LIGHT AND REFLECTION

By Randy Reid

Photographers: Tom Simpson, Cath Bowen

Copyright: ©NorthConnex Project Company / www.comms.store

The NorthConnex tunnel is a new nine-kilometer long road tunnel in Sydney, Australia. It is the longest road tunnel in the country and the first to be equipped with an innovative lighting system that merges art with technology to keep drivers alert and engaged.

The lighting system, awarded the lALD Award of Excellence, was designed by Lux Populi and features a variety of elements, including:

• A flock of reflective birds that change depending on the sky that they reflect from above.

• A canopy of trees that appear to be reaching over the tunnel walls.

• A starry sky that creates the illusion of driving through an outback highway.

The lighting is not only aesthetically pleasing but it's also functional. An attention management system breaks up the monotony of driving through a tunnel to help drivers stay alert. Different colors and patterns of light are designed to be visually stimulating without being distracting.

The lighting system helps to improve visibility for drivers, reduces glare, and saves energy, and the system's low maintenance design helps keep costs down over the 31-year contract.

Reflective Flight

The entrance to the tunnel isn't adorned with traditional art or routine lighting structures. Instead, it features a flock of birds made of mirrors that reflect the changing colors of the sky throughout the day.

With about a thousand birds in place, each mounted on a custom armature to determine its unique angle, the design is both intricate and strategic. Every bird is angled to reflect the sky without casting sunlight directly into drivers' eyes.

On days when the sky is blue, the birds echo that azure hue. On cloudier days, they might take on a whiter shade, and when the skies darken, they turn into black silhouettes.

The design's true beauty lies in its complete reliance on natural light and lack of external energy. This creates a visually captivating and net-zero art piece.

Apart from the art’s aesthetic appeal, the client primarily benefits from reduced energy consumption and maintenance. Unlike conventional lighting fixtures that demand consistent electricity and periodic replacements, this design is nearly maintenance-free.

Ensuring Safety

The beauty and innovation of this design didn't come without challenges. The potential risk of these birds reflecting sunlight directly onto the path of drivers was a significant concern. Approximately 2,000 hours of simulation were required to determine safe viewing angles and exclude areas with sun reflection.

The result is an intersection of design, engineering and sustainability that dazzles in its simplicity and function.

The reflective birds are a nod to the local biology of the Hills District of Sydney. The city is home to a large flocks of cockatoos, which are known for their playful and mischievous nature. The reflective birds serve as a reminder to drivers to enjoy the journey, even in a tunnel, and provide a glimpse of the real forests above.

The Canopy of Trees

Travelers heading south are met with a striking visual of trees in alternating shades of blue and white. More than just a visual treat, this design is a strategic masterpiece. Although it looks like a canopy of trees against the sky, it's actually a stencil print on metal sheets depicting the canopy's black silhouette against a white sky.

In Australia, sound panels along highways often obscure tree trunks from view. Capitalizing on this, the design emphasizes only the upper tree sections. Illuminated panels were added to spotlight the trees, giving the illusion that the top parts of the trunks are emerging in 3D from behind the panels.

This innovative design approach simplified the project. By making the tree canopy appear from behind the sound panels, only about seven and a half feet of the tree needed to be lit vertically. This resulted in notable cost savings, increased energy efficiency, and simpler maintenance.

The Color Choice: More Than Meets the Eye

The chosen blue for the design is a royal blue LED, a hue grounded in quantum physics and not dependent on phosphors, which can deteriorate. This ensures color stability over time. If a luminaire ever requires replacement, the brightness might vary, but the color remains consistent – an important factor when you can see hundreds of feet of product simultaneously.

Interestingly, this shade of blue sits just outside the optimum focal range for the human eye. Remember seeing those blue-lit signs that seemed slightly out of focus? This tunnel design leans into that phenomenon to create a sense of depth, as if the trees themselves are not being lit, but rather the vast sky beyond.

At its core, this design functions as an attention management system. The primary goal isn't just aesthetic appeal but to keep drivers awake and alert. The sudden change in light color serves this purpose effectively, enveloping drivers in a new quality of light that forces them to assess their surroundings. The repeating graphics are carriers for this light, designed to be engaging but not distracting.

The Starry Sky

Travelers passing through the tunnel experience a visually stunning transition that simulates a starry night. This effect is accomplished through the use of three layers.

First, the tunnel lighting changes from white to amber, creating the sensation of driving on an amber-lit highway in the outer suburbs and highways. Second, the concrete-sprayed tunnel's vault is uplit with a wide-beam version of the same product used for the tree visuals. Royal blue lighting is used to create a sense of depth and vastness.

The third layer is made up of stars represented by different brightness levels and sizes of LEDs, with some oriented at varied angles and wattages to produce different brightness perceptions for oncoming traffic. The stars also include retroreflectors, similar to cats' eyes on roads, that reflect headlights and exponentially amplify the number of star points without any added maintenance or energy consumption.

The design team achieved the authenticity of their design by superimposing a public-domain NASA star photo and adjusting the contrast to yield the desired number of star points. To avoid any recognizable constellations, they intentionally chose a segment of the northern night sky for use in the southern hemisphere, preventing travelers from identifying familiar constellations and reducing distractions.

Further along the tunnel, the design introduces a simulation of the starscape at warp speed, reminiscent of a classic sci-fi infrastructure and public-private partnerships are critical components in urban development, with the 31-year maintenance contract for this tunneling project serving as a prime example.

The project demanded a substantial investment for the lighting equipment, accounting for approximately 40% of the total cost. The maintenance contract extends over 31 years, with its cost estimated to be about 60% of the project's initial investment. This duration encompasses a 30-year operating lease, complemented by a one-year warranty handover, according to publicly available records. This structure ensures sustained functionality for the tunnel over three decades and provides a set period for necessary evaluations and updates.

The construction and maintenance responsibility rests with a joint venture among industry frontrunners: Transurban, Lendlease, and Bouygues. Transurban operates the project, Lendlease served as the builder, and Bouygues provided the tunneling. Their combined expertise ensures a holistic approach to the project.

Paving the Way for Innovations

The tunnel's design didn't just stop at merging aesthetics with safety. It became an inspirational beacon for other innovations. A recent development in Melbourne saw the inception of pacemaking lighting in a tunnel – a system where lighting chases along the tunnel at the speed one is supposed to travel, ensuring uniformity in driving speeds. While still in its early days, it underscores the possibilities that arise when design, technology, and safety converge.

Graphics and architecture surround us while driving, but we often ignore them. By contrast, lighting can capture our attention in a unique way. There is clearly a future market for tunnel attention management systems implemented in lighting.

Conclusion

The NorthConnex tunnel stands as a testament to the unbounded creativity that can be achieved when psychology, design, technology, and sustainability intersect. With its reflective birds, canopy of trees, and starry sky, the tunnel provides an experience unlike any other in the world. But more than an aesthetic marvel, it represents a commitment to safety, energy efficiency, and a reflection of culture and history. By pushing the boundaries of traditional tunnel lighting design, Lux Populi has paved the way for a future where roadways are not mere passages but immersive experiences. It serves as a shining beacon of innovation, creating a path that doesn't just lead to a destination but becomes a journey in itself.