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微观仿真技术能在交通影响评价工作中发挥重要作用. 依据交通影响评价的需求，设计了基于交通仿真的评价流程，包括数据准备、OD需求预测、参数标定等5个方面. 以北京市中关村西区交通影响评价为研究实例，针对中关村大街与北三环路交叉口及其上、下游交叉口交通组织存在的问题，提出了相应的改造措施，并依据VISSIM的仿真结果对所提方案进行了反复的修正. 仿真结果表明，路网两条主路的旅行时间和延误都相应减少，北向南方向的中关村大街平均速度由9.87km／h提高到12.53 km／h，排队长度由93.4 m减少到70.3 m，有效地缓解了主路的交通压力，说明了改善措施的有效性.

Traffic Impact Analysis using Microscopic Traffic Simulation Model

Microscopic simulation plays an important role in traffic impact analysis (TIA). Based on the demand of TIA,the paper designs the traffic impact analysis procedure with traffic microscopic traffic simulation,which includes data prepare,OD demand forecasting,and parameter calibration,and so on. Taking the western area of Zhongguancun in Beijing as an example,it develops some improvement measures with present situation,meantime makes some adjustment of the improvement measures according to the simulation of VISSIM. The simulation shows that the traffic time and delays of the main road are reduced,especially the traffic speed of Zhongguancun Street'is increased from 9.87 km/h to 12.53 km/h,and the average queue lengths reduced from 93.4 m to 70.3 m. The simulation results indicate that the improvement meastures are relatively effective.