Reducing the road freight emissions through integrated strategy in the port cities.

Port cities, as crucial nodes in global supply chains, face challenges from both intense traffic emissions and vulnerability to climate-related extremes due to pollution density. Effective and near-term mitigation strategies for greener road freight are imperative to reverse the increasing trend of emissions. This study utilizes a high-resolution emission inventory from 1.2 billion global positioning system trajectories of heavy-duty trucks in Shenzhen, a global port city, to evaluate the combined effects of road network development and fleet electrification on emissions from 2016 to 2035, providing a basis for policy interventions applicable to various urban contexts. Our findings reveal that an integrated strategy decreases road freight emissions, cutting peak carbon dioxide and nitrogen oxide emissions by 34% and 43%, respectively, compared to electrification-only scenarios. While fleet electrification supported by net-zero emission grids is necessary, it is insufficient without addressing congestion and enhancing connectivity through expanded road networks. Spatial projections also assist targeted policymaking by showing how emission distributions shift with regional road network expansion.