All Photons are Not Created Equal: Optimizing Intelligent Headlights under Adaptive Streetlighting Systems

Safety at night requires visibility. Visibility in turn requires lighting, and lighting, whether on vehicles or on poles along the street, requires energy. In addition to visibility, lighting can also produce glare, light pollution, and ecological disturbance. In response to these concerns, schemes for intelligent lighting that permit both vehicle lighting systems and streetlighting systems to adapt to environmental conditions, changes in traffic and pedestrian use, and needs for visibility are being developed and deployed. These advances offer significant promise for helping ensure safety while minimizing disruptive consequences, but it is not yet obvious exactly how, for example, adaptive vehicle headlights should adjust in response to adaptive streetlighting, and vice versa. Because of their different geometries, it is not necessarily beneficial to increase one type of lighting in response to reductions in another. In other words, all photons are not created equal. Visual performance analysis provides one tool for investigating which interactions between intelligent headlighting systems and adaptive streetlighting are desirable, and which may simply make things worse for pedestrians and drivers. The results from such analyses, shared in this paper, may help vehicle lighting engineers and the public streetlighting specification community develop compatible and sustainable solutions that can make road users feel safer and be safer.