Through dividing the expressway work zone into several control zones,the function and character of the control zones in the work zone are expounded.The operation of the vehicles in the work zones is characterized by the redistribution of the traffic flow in the work zones,vehicles on the left lane priority and mandatory merging.On the basis of a large number of traffic investigations, this paper deeply analyzes the distribution patterns of time headway of vehicles on left lane,right lane and merging lane,th...