<p>This study assesses the long-term impact of a transition from internal combustion engine trucks (ICETs) to fuel cell trucks (FCTs) in Japan. It integrates infrastructure investment cycles and equipment durability—including electrolyzers, compressors, and fuel cell stacks—into a dynamic stock turnover model, ensuring temporal alignment between fleet turnover and hydrogen infrastructure scalability. It also provides a granular, long-term (2025–2060) comparison of life-cycle GHG emissions and costs across diverse hydrogen pathways, including comprehensive evaluations of onsite renewable electrolysis versus offsite production with CCS, while distinguishing between medium- and heavy-duty truck dynamics. By integrating infrastructure durability with fleet dynamics and incorporating sensitivity analyses for technological uncertainties, this study offers insights for prioritizing hydrogen truck adoption and localized renewables. Results show that onsite wind electrolysis achieves the highest GHG emissions reduction (up to 35 million tons CO₂eq by 2040), while onsite solar electrolysis yields the lowest cost, generating $22 billion in economic benefits by 2040 over ICETs. These results underscore the importance of infrastructure investment and technological progress in shaping a low-carbon future for Japan’s road freight sector.</p> Graphical abstract <p>Fuel cell truck deployment process</p>