Embedding ‘‘roadside equipment’’ in the environmental assessment of transportation system: the case of safety barriers

The work arises from the consideration that the environmental impact of a road cannot be limited to the analysis of its constituent materials, even if correctly analyzed in their life cycle. In fact, a given road not only consists of the pavement and subgrade, but also includes several different components and accessories (e.g., road marking, drainages, safety barriers, etc.) that contribute to set a road infrastructure in operative condition. As a matter of fact, only limited attention has been paid in the scientific literature to roadside components, unlike pavement and traffic flow. In the present work, the environmental burden of one of these components, i.e., the safety barrier has been investigated using the LCA methodology and critically compared with that exerted by pavement and traffic flow, in order to establish their relative contributions. To accomplish this task, an application referring to a segment of a typical Italian highway is proposed. This case study seems to confirm that the environmental burden of the guardrail cannot be neglected, because it is often even numerically comparable with that of the pavements. This paper concludes that, in order to obtain a more comprehensive environmental evaluation, this type of analysis should be extended to this component and also to all of the other components and activities that make a road transportation system ready to be used. Such an integrated approach may be useful for administrations to better comply with the current sustainability standards and guidelines.