Bridge illumination with focus on conservation of natural environment

Citeos, the VINCI Energies brand that specialises in energy performance, low-emission mobility and the promotion and protection of urban spaces in France, has been appointed by the town of Blois to design and implement a lighting project for the Jacques Gabriel Bridge. Biodiversity conservation is a key priority in the project.

Optimising energy use while protecting ecosystems 

Artificial light is vital to human activity but harms biodiversity. It disrupts animal reproductive cycles and migration, disorients insects in flight and makes it harder for predatory species to hunt. The impact of light on plant life is even greater as it speeds up the flowering of plants, which grow by photosynthesis.   

To help prepare its tender, Citeos brought ecologists on board to identify what species have habitats in Blois, determine nesting periods and propose low-impact fittings. This high-tech equipment adapts night lighting to the requirements of human activity and protects ecosystems while reducing energy spend by half. 

Opting for a warmer colour of light 

The research conducted by Virginie VOUE, the Citeos co-contractor responsible for lighting design, showed that a warm amber light was best suited to conserving biodiversity, unlike other colours such as blue or white. Lighting colours were reviewed with this in mind and adapted to the season. 

Protecting the night sky and aquatic life  

None of the installed projectors are directed towards the sky so as to avoid sky-glow or towards the water to protect aquatic life. The projectors are turned off at 10.30pm with the aim of safeguarding species living in the area. 

The fact that the tender was put together with the help of ecologists is key to the success of the project, which represents a new opportunity for Citeos to stand out from the competition by making a lasting impact for future generations. 

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