Environmental sustainability for highways operation: Comparative analysis of plastic and steel screen anti-glare systems

The road construction is one of the main responsible for resource use and has been targeted as criterion development in updated versions of the Green Procurement Policy (GPP) in Europe. Although major progress was achieved in road pavements and lightning systems during the past decade, discussions on the environmental sustainability of additional road elements can advance the current understanding on how to decrease the impacts on highways. The aim of this study was to compare the potential environmental impacts of two anti-glare safety devices used on highways: the plastic (polymer-based) and the steel screen (steel-based). To this end, we applied the life cycle assessment (LCA) methodology following ISO standards based on a cradle-to-grave approach. The impacts of both anti-glare devices are driven by the main raw materials. This condition means that the weight of products is a key issue when evaluating the sustainability of the anti-glare devices. The plastic anti-glare (PAG) consumes significantly less materials and thereby presents the most favourable environmental performance for all the impact categories. For the products' manufacturing analysis, the hot-dip galvanizing was the process with higher impacts for both devices, as the setup kit of the PAG is also made from galvanized steel. Adopting sustainable strategies, e.g. product's recycling at end-of-life, use of recycled materials and product's setup with Li-ion battery, may provide an average impact reduction of 19% and 6% for the PAG and the steel screen anti-glare (SAG), respectively. A break-even situation for all the environmental impact categories occurs when the steel screen weight is reduced from 8.0 kg to less than 1.80 kg. Major attention has been addressed to road pavements and lighting system when evaluating the life-cycle impacts of highways, but our results highlight that the impacts of road sector can be offset by focusing in additional elements, such as the anti-glare device. (C) 2019 Elsevier Ltd. All rights reserved.