Effect of amber road lighting on visibility and safety for drivers and pedestrians

Providing adequate lighting has been linked with increased reassurance and visual performance for both pedestrians and drivers at night. However, increased light levels outdoors can contribute to light pollution, which is connected to negative ecological consequences, such as loss of biodiversity and circadian disruption. To reduce the negative impacts of light at night, narrowband spectra (amber lighting) have been championed as a better alternative to white lighting. Despite its proposed sustainable advantages, the visual performance and perception of safety under amber road lighting have not been systematically investigated. An in-situ experiment was conducted to compare the effects of phosphor converted (PC) amber and white LED lighting on small target visibility (representing navigational safety for drivers) and facial emotion recognition and color evaluation (representing assurance for pedestrians). No significant differences were found in small task visibility for drivers, nor face recognition between amber and white LED lighting at the same photopic level. However, white LED lighting positively affected pavement and color visibility and was associated with higher ratings of visibility for pedestrians. Results provide partial support for PC amber LED lighting as an alternative source with reduced short-wavelength emissions for road lighting without reducing driver visibility or facial recognition. Future studies should investigate the life cycle and other environmental costs which may be balanced against the higher energy efficiency of white LEDs.