Environmental sustainability of bicycles: methodological choices and climate impact

Road transport is an essential sector for social and economic development; however, it accounts for more than one quarter of greenhouse gas emissions in the European Union. In this context, bicycles represent a promising alternative mode of transport for reducing dependence on fossil-fuel-based mobility and contributing to greenhouse gas emissions reductions. Several studies have applied the life cycle assessment (LCA) methodology to quantify and compare the environmental performance of conventional and electric bicycle production, as well as the implications of different types of use (shared and private), revealing a wide variation of results across the literature. This work reviews 28 papers on LCA, focusing on identifying trends in assessing how methodological choices, including functional unit (FU) and the system boundaries, influence the reported global warming (GW) results – ranging from 0.0015 to 0.32 kg CO₂eq·pkm⁻¹ for conventional bicycles and 0.016 to 0.15 kg CO₂eq·pkm⁻¹ for electric bicycles. Overall, this study indicated that within bicycle-sharing systems, conventional bicycles had a higher GW impact than electric bicycles, mainly due to their shorter lifespans and lower daily turnover rates. In contrast, in private-use systems, the electric bicycle had a greater impact than conventional bicycles, mainly due to its additional electronic components. This review highlights the need for more comprehensive approaches that integrate environmental, economic, and social sustainability and explicitly account for the diverse types of bicycle use.