In 2023, after more than five years of design and construction, Allegheny County (Pennsylvania, United States of America) completed the structural renovations and installation of an enhanced lighting system on the three Sister Bridges. To mark the occasion and introduce the lighting system to the world, the County worked with Pittsburgh’s Office for Public Art to commission an artist to create the inaugural lighting design for the new bridge lighting system. Through a competitive regional submission process, artist and designer Rob Long was selected to create the first dynamic lighting concept for these unique and historic structures.

“Observing Light” – a concept for the Sister Bridges that applies the impressionistic color and motion of reflected light to the iconic bridges of Pittsburgh. At the heart of this design is a dynamic series of light reflections – authentic video content captured along Pittsburgh’s Three Rivers. This imagery, displayed on state-of-the-art linear LED fixtures affixed to the vertical suspenders, brings the bridges to life with understated abstract movement and vibrant colorplay. The Tower features, standing prominently, are bathed in a soft, warm glow, while additional lighting elements harmonize with the artistic imagery, creating a seamless blend of architecture and art. ”Observing Light” is a contextual design that celebrates the act of seeing, light and water in the City of Bridges.

The artist sought out locations along Pttsburgh’s rivers where reflections of natural and artificial light were abundant and alluring. The video content was captured over a period of three weeks in the fall of 2023, with locations selected along each of the region’s three rivers based on the quality of light and the movement and flow of the waterway. One of the key considerations in the design development was the smooth and engaging playback and legibility of video imagery. The pacing and speed of the video content was meticulously adjusted to ensure a mesmerizing experience from vantage points near and far. This reflects the artistic team’s mindfulness of the County’s objective – to celebrate the historic structures through a lighting design that is not only creative but also restrained, sophisticated, and relatable.

The designer behind this project, artist Rob Long, draws on his dual expertise as a photographer and architectural lighting designer. Inspired by the design brief, he envisioned a synthesis of his creative work and professional practice, delivering a memorable and practical solution for the Sister Bridges. The lighting system serves as a technological platform perfectly suited to showcase abstract interpretations of movement and color. For Rob, this project represents the convergence of two artistic passions – lighting design and visual storytelling.

The Sister Bridges lighting system is not just an aesthetic enhancement but a thoughtful exploration of technology, art, and history. It transforms the bridges into dynamic canvases that tell a story through light, inviting the community to engage with and appreciate the historic structures in a new and captivating way. “Observing Light” is a testament to the power of creative collaboration, technological innovation, and a deep appreciation for the interplay between light and architecture in an urban context.

Rob Long’s work on the Sister Bridges lighting design was supported by his team at Clear Story, a design firm he founded in 2007 to serve as a vehicle for his creative practice. Programming Specialist Peter Milo and Video Specialist Sean Starr were integral collaborators on the project. “Observing Light,” a temporary design commission for the Sister Bridges, was launched on November 18, 2023 and runs through January 1, 2024.

History & Context:

Built between 1924 and 1928 by the American Bridge Company, the Three Sisters are historically significant because they are the only trio of nearly identical bridges, as well as the first self-anchored suspension spans, built in the United States. They are among the only surviving examples of large eyebar chain suspension bridges in America, and furthermore, unusual for their self-anchoring designs (from Wikipedia).

Designed by the Allegheny County Department of Public Works, they replaced earlier bridges at the same sites and were a response to navigable river clearance concerns mandated by the War Department. The trio of bridges, located at 6th, 7th, and 9th streets, are named after iconic Pittsburgh residents: Roberto Clemente, Andy Warhol, and Rachel Carson.

Supplier Partners

Lighting Designer Partners

Trophies created by

Photo Booth created by

Supported by

Organised by

In collaboration with