An early-stage, multi-lifecycle assessment framework for sustainable material selection in automotive industry

The transition toward low-carbon mobility requires material-selection approaches that account for extended use cycles and cross-sector reuse pathways. However, early-stage automotive design decisions are typically informed by single-life cradle-to-grave assessments, which do not explicitly integrate reuse-induced substitution effects or multi-stage emission accounting within development timelines. This study operationalizes an integrated cradle-to-reuse-to-grave (C2R2G) assessment approach by combining established life cycle assessment (LCA), system expansion, and substitution modeling principles into an automotive-specific decision-support structure. The framework formalizes emission accounting across primary use, reuse preparation, secondary application, and end-of-life treatment, including explicit system expansion, substitution, and circular scenario modeling parameters. A bio-based laminated veneer lumber (LVL) seat-shell is evaluated as a demonstrative case within passenger vehicle applications. Scenario modeling compares single-life, recycling, and open-loop reuse pathways under varying lifetime and energy-intensity assumptions. Results indicate that reuse-driven substitution effects can significantly alter cumulative carbon footprints compared to single-life configurations, though outcomes remain highly sensitive to assumed service lifetimes, displaced material emission factors, and energy mixes in second-life sectors. Sensitivity analysis highlights key parameters influencing ranking stability and identifies boundary conditions under which reuse advantages diminish. Rather than proposing a new LCA methodology, this work demonstrates how established analytical components can be systematically integrated to support early-stage automotive material pathway evaluation. The approach enhances transparency in allocation choices and trade-off identification, contributing to more informed low-carbon design decisions in circular mobility systems.