Truck vs high-speed rail express delivery: The social welfare and environmental implications

The express delivery industry, driven by e-commerce, has experienced rapid growth. To meet rising demands for speed, reliability, and environmental sustainability, high-speed rail (HSR) is increasingly used for express parcel delivery (HSR express delivery, HSReD), creating both trunk-line competition and first/last-mile complementarity with traditional trucking in the express delivery market. In this study, we develop an economic model to analyze this intermodal interaction under an explicit HSR capacity constraint. We examine three scenarios: (1) a truck-only benchmark in which the express delivery market is served solely by trucks while HSR carries only passengers; (2) intermodal competition in which both trucks and HSR provide express delivery, with HSR also serving passengers; and (3) government intervention in which an emission tax or subsidy on HSReD is used to balance social welfare and environmental impacts. Our findings show that, at short intercity distances, introducing HSReD generally raises carbon emissions but may nonetheless improve social welfare if the two modes are weak substitutes or, when substitution is strong, if HSR capacity is sufficiently large. At longer distances, HSReD improves both social welfare and environmental outcomes when HSReD and trucking are strong substitutes. We also find that subsidies for HSReD may be justified when welfare gains are substantial, even if environmental impacts are negative. Overall, our analysis provides economic insights into HSReD and offers policy recommendations for promoting a more sustainable and efficient transport system.