A novel approach for environmental impact assessment of road construction projects in India

The road sector is one of the basic pillars for national economic growth owing to its role in movement of goods and people and can contribute positively towards several sustainable development goals (SDGs). On the other hand, road construction using conventional methods can jeopardize the global progress towards climate action and other environmental related SDGs owing to large raw material requirements, fuel demand and pollution associated with it. Life cycle assessment (LCA) is a useful quantitative tool to figure out which products and processes are responsible for majority of road's environmental impact at different stages. This information can then be used to design interventions and adopt alternative materials for improving the environmental profile of roads. However, the application of LCA in road sector in developing countries such as India has been limited owing to unavailability of funds to compile information regarding quantities of all materials used (inventory data) and their environmental characterization factors. Here we present a new approach that connects the publicly available road's bill of quantity (BOQ) and analysis of rates (AOR) documents with national construction materials environmental footprint database to calculate the road footprint. A case study on calculating the environmental impacts of a recently built 43 km state highway road in the Indian state of Gujarat is presented to demonstrate the steps involved in the new approach. The environmental impacts per kilometre of the road section came out to be 6.86 million MJ energy use, 281 tons CO2eq. GHG emissions, 0.013 kg CFC-11 eq. ozone depletion, 2.16 tons SO2eq. acidification, 0.35 tons PO4eq. eutrophication and 0.11 tons ethene eq. of photochemical oxidant formation. Among all life cycle phases, the material production stage contributes the highest to the total environmental footprint of the road section. Of the 52 materials used, bitumen, diesel, coarse/fine aggregate, galvanized iron (GI) pipe, concrete, thermoplastic paint used in road markings and steel corrugated sheet and channel post are responsible for majority of impacts. The template presented can be used in India and other developing countries to evaluate the environmental footprint of existing and future road projects.