Advancing environmental mitigation on the Bretagne Pays de la Loire railway, France

The new 182 km Bretagne-Pays de la Loire high-speed rail line in France has pioneered the use of an environmental mitigation hierarchy, leading to significant sustainability benefits. As this paper describes, the project has gone beyond regulatory obligations and contractual provisions for sustainability, particularly regarding biodiversity and carbon dioxide emissions. It has opened up a more sustainable way of conceiving and building transport infrastructure, with extensive collaboration, innovative organisation, technical and operational tools and a long-term, efficiency-based offsetting approach. Early adoption of the mitigation hierarchy principle on this project enabled the worksite footprint to be reduced by 8% and avoided the emission of 4.5% of greenhouse gases associated with the line's construction. It also accounted for biological cycles during work planning and secured the ecological offsetting sites before construction started, which in turn ensured their functionality over a 20-year period to ensure no net loss of biodiversity.