交通小区划分对路网流量分配结果的影响分析

不同交通小区划分方法会产生不同的路网流量预测结果,如何选择合适的划分方法使预测结果更为精确至关重要.以西班牙马德里主干道路网为对象,采用OD反推算法,利用交通规划软件TransCAD,研究在交通小区个数相同的情况下,按行政区划和按人口分布2种不同聚合方法划分交通小区对路网流量预测结果的影响,即可变面元问题中的聚合区域形状影响.结果表明,按人口密度划分交通小区预测的路网流量结果与实际值更接近.将按人口密度划分的交通小区进行3种不同程度的再次细分,比较交通小区数量对路网流量预测结果的影响,即可变面元问题中基本单元大小的影响.研究表明,路网流量预测结果的精确度随着交通小区数量的增加而提高.考虑人口分布等交通地理信息数据划分交通小区能更好地预测出未来年路网交通流量,并且交通小区划分的越细,预测结果与实际值越接近. 

Effects of Dividing Methods for Traffic Analysis Zones on Distribution of Road Network Flow

Different designing methods for Traffic Analysis Zones (TAZs) may lead to different forecasting results of traffic flow.It is important to select an appropriate dividing method to improve the precision of forecasting results.This paper takes arterials of Madrid, Spain as a case study to analyze the effects of different aggregation methods of TAZs.TransCAD software and a method of OD matrix estimations are adopted.Firstly, the effects of aggregating TAZs based on administrative districts and population distribution zones on forecasting results of distribution of road network flow are investigated.The number of TAZs is kept the same for different aggregation methods, namely the zonation effects on modifiable area unit.The results show that the dividing method for population distribution zones produces a result closer to the actual value.Then, the population distribution areas are further divided into three different degrees to compare the effects of number of TAZs on the forecasting result of road network flow, namely the scale effects on modifiable area unit.The results show that the accuracy is improved when the number of TAZs is increased.By incorporating population distribution or other traffic-geographic information into TAZs dividing, traffic flow of future years could be better predicted, and the smaller the TAZs are divided, the closer the prediction results would approach the actual situations.