在“双碳”政策的时代背景下，交通行业碳减排任务艰巨，但目前面临车辆碳排放测算精度不高的问题。为实现车辆碳排放的精细测算，文中提出了一种融合多源数据的高速公路路段车流碳排放精细测算方法。首先，运用KD-树算法将运营车辆的GPS坐标与高速公路道路点坐标搜索匹配，实现对运营车辆的实时监测。然后，建立车辆碳排放测算模型，进而设计相关的计算流程。最后，以虎门大桥主桥段为例进行路段断面碳排放测算，通过VISSIM仿真及相关对比实验，验证了文中所提出的算法的科学性和可靠性。结果表明：按车辆类型分类，微型小型客车的碳排放最高，占比达74.36%；按燃料类型分类，汽油车的碳排放最高，占比达80.50%；新能源汽车运行车次数占12.60%，但碳排放仅占4.27%，因此大力发展新能源货车是推进高速公路碳减排的重点。研究还发现，将交通饱和度控制在0.32~0.38时，当量标准车的平均碳排放较少；当交通饱和度大于0.62时，当量标准车平均碳排放显著增加。文中研究结果可以为交通管理部门制定相关策略提供理论依据。

In the context of “dual-carbon” policy, the task of carbon emission reduction in transportation industry is arduous, but the vehicle carbon emission currently cannot be measured accurately at present. In order to realize the fine calculation of carbon emission, this paper proposes a precise calculation method of traffic carbon emission in expressway segment based on multi-source data. Firstly, KD-tree algorithm is used to match the GPS data of operational vehicles with the road points, thus implementing the real-time monitoring of dynamic vehicles. Then, the calculation model of vehicle carbon emission in road segment is established, and the relevant calculation process is designed. Finally, the main section of Humen Bridge is taken as an example to calculate the carbon emission of the section. Through VISSIM simulation and relative comparison experiments, the science and reliability of the proposed algorithm are verified. The results show that, for different vehicle types, the carbon emission of minibus is the highest, accounting for 74.36%; and that, for different fuel types, the carbon emission of gasoline automobile is the highest, accounting for 80.50%. The new energy vehicles in operation account for 12.60% of the total vehicles but the corresponding carbon emission only accounts for 4.27%, which means that energetically developing new energy trucks is the key to the carbon emission reduction of expressways. It is also found that, when the traffic saturation is controlled at 0.32~0.38, the average carbon emission of equivalent standard vehicle is lower; while when the traffic saturation is greater than 0.62, the average carbon emission of standard vehicle increases significantly. These conclusions provide theoretical basis for traffic management departments to formulate relevant strategies.