Carbon accounting and decarbonization pathways in road construction: a systematic review and research agenda

• A systematic review of carbon accounting and decarbonization in road construction is conducted • Comparative applicability of P-LCA, IO-LCA, and Hybrid-LCA models is analyzed • Synergistic pathways linking source-side mitigation and carbon-sink enhancement are synthesized. • Research hotspots and interdisciplinary evolution are identified via CiteSpace analysis. • A digital-twin and MRV-oriented framework is proposed for dynamic carbon management. With the advancement of China’s “dual-carbon” strategy, carbon emissions generated during the construction phase of road infrastructure have emerged as a critical issue in the pursuit of sustainable transportation development. This review systematically examines recent advances in carbon accounting and decarbonization in road construction and proposes an integrated analytical framework linking accounting, mitigation, and sequestration. Three life cycle assessment paradigms, namely, process-based, input–output, and hybrid, together with mass-balance analysis, field measurement, and emission-factor estimation, are compared in terms of applicability and data integration. From the perspectives of both emission-source control and carbon-sink enhancement, diverse mitigation strategies are summarized, including energy substitution, low-carbon materials, digital and intelligent construction, slope greening, and carbon-sequestering technologies. The review highlights evolving research hotspots, methodological shifts, and trends in interdisciplinary integration. Furthermore, it identifies future priorities in multisource data fusion for carbon accounting, system-level optimization of mitigation pathways, and long-term assessment of carbon-sequestration performance through standardized monitoring–reporting–verification systems. This study provides methodological insights and a strategic roadmap for the low-carbon transformation of road infrastructure.