Balancing the needs of transportation and ecological systems often focuses on overpass, underpass, and culvert structures that increase mobility for iconic species at significant taxpayer cost. At the same time, there exist low-cost opportunities for eco-friendly road maintenance policy adaptations and practices that equally demonstrate ecological accountability to an informed and interested public, but benefit a larger number of species and do so with little or no incremental budget impact.
Wildlife foraging behaviors, predation behaviors, detection and escape of prey, reproductive functions, movement and navigation, communication, and vision health are all susceptible to the disruptive effects of transportation-related light pollution. This session reviews a selection of these evidence-based consequences of transportation system lighting on wildlife, gleaned from a compilation and analysis of scientific literature reviews conducted in 2017 and 2019. Examples will be presented, such as smooth asphalt road surfaces that reflect and mimic polarized light, confusing water-seeking insects that rely on on polarized light for navigation. Roadway lamps emitting light beyond a human-visible spectrum turn night to day for many terrestrial species, with little discernible benefits to drivers or safety. The sky glow of coastal road lighting deceives species dependent upon land mass silhouettes or stars against an ocean horizon for navigation, to tragic effect. And, light receptors in nocturnal mammalian and vertebrate eyes are blinded by passing vehicle headlights, some temporarily, and others permanently.
Fortunately, lower-cost, eco-friendly mitigating solutions to these harmful effects are being advanced through scientific knowledge and the development of transportation technologies, providing practitioners new opportunities to integrate thoughtful, adaptive maintenance practices where roads and bridges bisect natural landscapes. In this session, budget-friendly maintenance practices and applied management solutions for mitigating road lighting effects on terrestrial wildlife will be shared, including replacement lamps with spectrums that minimize anthropogenic interference with natural functions, new lighting fixture designs to reduce sky glow impacting coastal wildlife, non-polarized-light-reflecting road sealants for uses on bridges and near waterways to protect aquatic life, and natural approaches to shading and blocking harmful road lighting and wildlife-blinding headlamp beams. These are low-cost changes in maintenance practices that, when promoted, can demonstrate a community's environmental friendliness with minimal investment.