Cross-sectoral and spatial impacts of carbon neutrality on China's transport sector emissions: A 31-region CGE analysis

China's carbon peaking and carbon neutrality strategy is reshaping the national industrial structure, yet its cascading effects on the transport sector—a critical economic pillar and major emission source—remain insufficiently understood, particularly regarding industrial-chain and regional transmission mechanisms. This study addresses this gap by quantifying how upstream and downstream industrial restructuring under carbon-neutrality policies propagates into transport-sector output and emissions. Using a multi-regional Computable General Equilibrium model (IMED|CGE) covering China's 31 provinces, combined with structural path decomposition, we trace the industrial and spatial pathways through which policy-induced emission reductions are transmitted to the transport sector. Results show that carbon-neutrality policies trigger a systemic transformation of transport demand by restructuring upstream industries, reducing transport CO2 emissions by 43.1% in 2060. The contraction of energy-intensive sectors (e.g., coal mining, metal smelting) sharply reduces intermediate transport inputs (by 26.9 and 28.3 billion USD in 2060, respectively), curtailing high-carbon bulk freight demand. Conversely, the expansion of low-carbon services boosts transport demand by 87.0 billion USD, driving a structural shift toward high-value, lower-emission logistics. Transport electrification and energy-efficiency gains amplify these effects. Spatially, energy-exporting provinces (e.g., Shanxi and Inner Mongolia) achieve the largest emission reductions (up to 78.4%), with dominant pathways concentrated in energy-supply chains driven by inter-provincial exports. In economically diversified regions (e.g., Guangdong, Chongqing), reductions are primarily demand-side driven, linked to local construction and service activities. These findings suggest that differentiated strategies that prioritize upstream green energy supply and downstream low-carbon demand management are essential for a coordinated green transition in China's transport sector.