The Carlisle Southern Link Road uses 379 luminaires equipped with NightTune technology that adjusts lighting levels and colour temperature as night progresses. This reduces blue light output by 18% on a major 8km route through the Cumbrian countryside.
The new link connects Junction 42 of the M6 with the A595 at Newby West. It forms part of a £259.4 million investment to ease congestion and support growth around Carlisle. The lighting design balances road safety with reducing ecological impact beyond the carriageway.
A lighting scheme tuned to its environment
Cumberland Council required compliant lighting for drivers and pedestrians alongside the road that also minimised disturbance to nocturnal wildlife and the rural landscape. This shaped the choice to use adjustable colour temperature and dimming rather than a fixed LED solution.
Craig Lensky, Key Account Manager at Thorn Lighting, said the ecology brief was integral from the start: "We had to provide the right light for people using a major new road but also think carefully about what that light was doing beyond it and throughout the night."
The shared-use walking and cycling route alongside the road includes an unlit section at Caldew Crossing to further limit environmental impact.
NightTune adjusts light and colour
The 379 R2L2 road lanterns range from 1,800 to 30,000 lumens and 20W to 260W. NightTune varies output and warmth in steps: 2700K at full output until 9pm, 2400K at 50% output until midnight, and 2200K until 5am. Output and warmth then ramp back up before dawn.
This reduces the shorter-wavelength blue light that can disturb wildlife. Thorn’s research shows these warm, dimmer settings better balance human safety with ecological needs.
Designed not compromised
Thorn developed customised optics on the R2L2 platform to maintain road lighting standards despite changing light colour. The council considered fixed-colour alternatives but remained committed to NightTune’s environmental benefits.
Craig Lensky noted: "The council had a very clear ambition. Our job was to make that ambition technically achievable, not to dilute it for simplicity."
Energy savings and dark sky protection
NightTune also reduces energy use by dimming lights according to reduced nighttime road and pedestrian activity. Comparing NightTune with a fixed 3000K dimmable scheme reveals an average 13% reduction in blue peak and 18% reduction in low-wavelength output.
All luminaires were installed at zero tilt. R2L2 holds independent Dark Sky Approval at 3000K and below, limiting upward light spill to protect night skies.
Setting a new benchmark for rural roads
Adam Williamson, Lighting Manager at Cumberland Council, said: "The scheme shows safety and environmental responsibility can go hand in hand. NightTune enabled us to adapt lighting through the night rather than accepting fixed settings."
The Southern Link Road opened to traffic in June 2026. Its lighting now follows the night’s rhythm, providing light where and when people need it, reducing output when activity falls, and shifting to warmer light during peak nocturnal wildlife activity.
This project demonstrates what NightTune can achieve at scale on UK strategic roads passing through sensitive environments.
