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针对四车道高速公路的单向行车道封闭施工、单向超车道封闭施工、半幅封闭施工、半幅封闭施工过渡区段的施工作业区进行调查，并分析施工作业区各主要区段的地点车速，确定平均车速、85%位车速、各区段间的车速差、大小型车间的车速差，以及各区段相对于现场限速值时的超速比例等车速分布特性.得出，从上游正常路段至警告区（或过渡区）再至施工区车速分布的标准差在明显减小，同时小型车与大型车的车速差也在明显减小等统计分析结论.最后，根据车速分布规律给出了作业区车速控制原则，以及基于车速统计分布特征的作业区各区段限速值建议.

Speed Distribution Characteristics and Speed Limits of Freeway Work Zones

This paper analyzes the speed distribution of each main component on four kinds of freeway work zones: the closed one way running lane work zone, the closed one way passing lane work zone, the closed one way lanes work zone and the closed one way transition region work zone. It determines the average speed, the 85th speed, the speed difference of each component, the speed difference between oversize and light vehicles and the over speed vehicles’ percentage related to limited speed values. Then, some statistical conclusions are drawn: the standard deviation of vehicles’ speed distribution is gradually decreased throughout upstream normal area, warning area (or transition area) and activity area of work zones; the speed difference between oversize and light vehicles also decreases obviously. In the last section, the paper proposes speed control principles and limited speed values of each component on freeway work zones considering the characteristic of speed statistical distribution.