How Does China’s “Ten Cities, Thousand Vehicles” NEV Promotion Project Affect Carbon Emissions from Urban Logistics?—An Empirical Analysis Based on the Multi-Period Difference-in-Differences Model

Under the “dual carbon” strategic framework, the low-carbon transition of the logistics sector—a major source of carbon emissions in the national economy—has become imperative for achieving green development. The adoption of new-energy vehicles (NEVs) represents a critical pathway for decarbonizing logistics operations. Initiated in 2009, China’s “Ten Cities, Thousand Vehicles” Demonstration Project served as a pioneering policy to accelerate NEV deployment, offering a valuable use case for reducing emissions in urban logistics. Using this initiative as a quasi-natural experiment, we employ a multi-period difference-in-differences (DID) approach and panel data from 275 Chinese prefecture-level cities (2000–2021) to evaluate the causal effect of the policy on urban logistics CO2 emissions. The robustness of the findings is confirmed through parallel trend tests, placebo tests with reassigned treatment timing, alternative dependent variable construction, and instrumental variable estimation. Mechanism and heterogeneity analyses are further conducted to uncover underlying channels and contextual variations. The results indicate a statistically significant reduction in logistics carbon emissions in pilot cities, which remains consistent across multiple robustness checks. Mediation analysis reveals that the policy effect is partially transmitted through increased NEV stock. Moreover, the emission reduction effect is more pronounced in cities with lower logistics dependency and non-consumer-oriented economic structures, while it is weaker in consumer and highly logistics-dependent cities. These findings confirm the sustainable contribution of early NEV policies through advancing the transition to low-carbon logistics and supporting dual carbon goals, fill the empirical gap in developing countries’ freight decarbonization, and offer actionable insights for targeted regional sustainable logistics strategies.