通过实测数据对交通参量进行统计分析并建立交通荷载模型是分析桥梁车辆实 际荷载水平的一种常用方法，但其合理性尚未得到理论验证．文中利用车辆动态称重系统 ( WIM) 实测获得 6 条公路 28 条车道上的车辆信息，构建各车道上的一维随机车流类型 场; 按照随机过程理论计算得到所构建各车道一维随机车流类型场的集合均值与集合相 关函数、空间均值与空间相关函数等． 对比分析结果表明，基于实际公路上足够数量车辆 的调查所构建的一维随机车流类型场具有平稳性和各态历经性，其样本的统计信息能够 代表总体样本，可以用于车辆随机荷载的研究，为公路桥梁随机车辆荷载模型的建立提供 了理论依据．

Using the measured data to statistically analyze traffic parameters and then construct traffic load models is a popular approach to the estimation of the actual bridge load effect of random motorcade on bridge． However， the rationality of such an approach has not been theoretically verified till now． In this paper，based on the vehicle information collected by the weigh-in-motion systems ( WIM) on 28 lanes of six highway bridges，the 1-D random field of vehicle type of traffic flow on each lane is established． Then，the numerical characteristics of the established random fields，such as the ensemble means，the collection of correlation functions，the spatial means and the spatial correlation functions，are calculated according to the theory of random process． Analytical results show that the 1-D random fields of vehicle type of traffic flow，which are established through the survey on adequate vehicle samples on actual highways，are of stationarity and ergodicity，and the statistical information of the samples can represent the total samples． Besides，the established random fields can be used to further investigate the random vehicle loads and can provide a theoretical basis for modeling the random vehicle load on highway bridges．