# Life Cycle Analysis of Road Construction and Use
## 1 Introduction  
In recent years, environmental aspects related to road infrastructure construction have increasingly come under examination [1; 2] in order to apply environmental award criteria in calls for tender [3] and introduce the green public procurement (GPP). At the international level, several efforts have been made to apply GPP to the road sector: in Sweden, environmental aspects are integrated in road maintenance contracts [4; 5; 6]; in Finland, procurement methods are implemented to reduce the environmental impacts of roads [7]; in the Netherlands, GPP has been implemented to manage the main road network [8]. Currently, the Italian Ministry of the Environment is transposing the meaning of the document \"Green Public Procurement Criteria for Road Design, Construction and Maintenance\" published in 2016 by the European Union [9] to encourage the purchasing of products, services and works with reduced environmental impacts. Four criteria are proposed to assess the life cycle impacts of road construction: Life Cycle Impact Assessment (LCIA), Carbon footprint (CF), recycled and re-used content, and Low emissions from transport of heavy materials. The listed criteria have decreasing levels of ambition and technical complexity: in literature the most frequently adopted frameworks are LCIA and CF [10; 11; 12; 13]. LCIA is a holistic assessment tool which considers different environmental impacts (e.g., acidification, eutrophication, abiotic depletion), while CF only evaluates the total amount of greenhouse gas emissions of road processes: CF is the result of a partial LCIA implementation. Recycled and re-used content and low emissions from transport of heavy materials focus respectively on the content of used recycled, re-used or by-products materials, and on CO\({}_{2}\) emissions from the transportation of aggregates. These last two approaches are alternatives to LCIA and CF, and it is recommended to combine both in order to achieve an overall environmental benefit. According to the EU environmental objectives and data available in the literature, authors adopted theLCIA because it allows a quantitative and robust evaluation of each examined process [14]. Indeed, the unbiased and comparable results from LCIA depend on the specific production chain, it takes into account the specific boundary system and operational conditions, and could be adopted as an effective environmental decision support system [15]. Since the early 2000s, some research has used the life cycle assessment methodology to assess the environmental performances of a road and its different stages. With different analysis periods and functional units, they examined the environmental impacts of road materials [16; 17; 18; 19; 20] and compared construction techniques and maintenance activities [10; 21; 22; 23; 24; 25] with different methods and software. [PERSON] et al. [21] used the software Copert 4 [26] to assess the overall environmental impacts and primary energy associated with earthwork and pavement processes. [PERSON] [22] applied the impact assessment method ReCiPe [27] to construction and maintenance activities of two highway projects in southern Norway in order to identify the main aspects affecting LCA results. Burdens of traffic are not considered. According to EN 15804 [28], [PERSON] et al. [23] assessed the environmental and human health impact of construction of two different road cross-sections (i.e., embankment and trench sections). [PERSON] et al. [24] used the tool ERM (elementary road modulus) [29], to assess LCA of construction and maintenance activities three different road pavements. The EU project ECRPD [25] assessed impacts of wearing layers during their construction and maintenance, whereas initial phases of road and pavement construction (e.g., subgrade preparation and subbase construction) were excluded.