Short-time forecasting method for traffic flow based on urban macroscopic road network model

The invention relates to a short-time forecasting method for a traffic flow based on a macroscopic road network model, which comprises the following steps: (1) obtaining the input flow of the source node of a road network at a forecasting period, extracting the average speed of each road section at a previous forecasting period and determining the flow ratio of different turning directions at each intersection; (2) calculating the time of vehicles running to the tail of a queued vehicle queue, which are input on a road so as to obtain the number of the vehicles arriving at the tail of the queue at an iterative period; (3) determining the number of the vehicles which are correspondingly turned to leave the intersections by the conditions of the number of the vehicles queued at the intersections, the saturated leaving flow and the like; (4) accumulating to obtain the total number of the vehicles leaving the intersections at one forecasting period and converting to obtain the traffic flow within the forecasting