Development of traffic flow model for estimating vehicle emissions accuratery

本研究旨在建立精确的交通流模型来估算汽车的环境污染量，主要包括以下四个方面的内容。1)交通流量波动特征分析，2)交通调查精度分析，3)利用调查得到的各路段交通流量修正OD估计出行量，4)货车驾驶员路径选择决策特征分析。研究结果表明：(1)东京主干道交通流量的波动幅度约为日均交通量的3-5%。波动可以分为随机波动和系统波动。这两种波动比约为6：4。(2)人工计数交通流量调查除随机误差外，还存在负系统误差。当采用问卷调查法进行OD出行调查时，有20%-30%的出行遗漏。几乎所有的遗漏出行都是这样的：家庭周边的短途出行、长途小费途中顺道拜访的出行以及一天出行次数较多的人的出行。(4)使用精确的路段流量可以大大提高OD出行估计的准确性，特别是在OD出行具有较大系统误差的情况下。我们很遗憾地说，他们仍然是未来的研究对象。

This study aims at developing a precise traffic flow model for estimating the amount of environmental pollution discharged by cars, and consists of following four subjects. 1) analysis on characteristics of traffic flow fluctuation, 2) analysis on accuracy of traffic surveys, 3) developing a technique to revise estimated OD trips using surveyed each link traffic flow volume, 4) analysis on characteristics of route choice decision of freight vehicle drivers. The results are summarized as follows.(1) The range of fluctuation in traffic flow on the principal road in Tokyo is about 3-5% to the average daily traffic volume. The fluctuation can be divided into random and systematic fluctuation. These two fluctuation ratio is about 6:4.(2) In addition to random error, manual count traffic flow surveys have a negative systematic error. The size of negative systematic error becomes larger with a number of vehicles counted.(3) When OD trips are investigated by the questionnaire survey method, 20-30% of trips will be missing. Almost all of missing trips are as follows; short distance trips around the house, trips which drop in for a short visit on the way of a long distance tip, and trips done by a person who has a lot of trips in a day.(4) The accuracy of OD trips estimation is greatly improved by using exact link flow volume, especially in case that OD trips has a large systematic error.Although several analysis have been tried on characterstics of OD trip fluctuation and characteristics of route choice decision of freight vehicle drivers, we can not get reliable results on these subjects within the term of this study. We are sorry to say they remain as future study subjects.