VMT Estimation Model Based on Traffic Counts and Link Attributes

Abstract

Abstract: VMT estimation is essential in many transportation related engineering areas including emission estimation . Since the actual value of VMT is impossible to obtain by the current technologies,VMT has to be estimated from other information. Two broad divisions of VMT estimation methods exist, namely thenon-traffic –count-based methods and the traffic count-based methods. Both have their own advantages and shortcomings. Traffic-count-based methods are more popular in real practice. However the traffic-count-based methods simply extend traffic count onto other links, which have the same road class as the count station without considering the effect of the link attributes on the VMT. This paper developed an alternative approach that can incorporate both traffic count and link attributes through an exponential regression model in estimating volume and VMT. The model coefficients can be calibrated easily in the real-world. To meet the requirements of the application of emissione stimationbyMOBILE6, disaggregating of the estimated VMT by speed and time is further conducted. Due to the lack of the required data to validate the estimation process
and the effectiveness of the proposed model in China, we conducted the test based on relative traffic data obtained from the southwest region of Houston, U.S.A.By comparison, VMT estimation by the proposed model is closer to the full size estimation than the EPA Traffic Count Method(TCM). The emission estimation by VMT from this method is also better than those from both the MOBILE6 default VMT and the EPA TCM method.

Key words: vehicle miles traveled, volume estimation, exponential regression, air quality analysis

摘要： 车辆行驶里程(VMT)估算是包括尾气评估在内的许多交通工程相关领域研究工作的基础.由于在现行的技术条件下难以得到VMT的真实值,VMT只能根据其他信息估测获得.目前主要使用的两种方法是“基于交通量方法”和“非基于交通量方法”,这两种方法各有其优缺点.在实际操作中,“基于交通量方法”的应用更为广泛，但不足之处是，它仅仅将采样得到的交通流量数据简单用于其它具有相同道路等级的路段上来估测VMT,而没有考虑各路段的具体特征对VMT的影响.本文提出了一种新的VMT估算模型,该模型引入指数回归模型,结合采样交通流量和路段特征来估测流量和VMT.在实际运用中,该模型在现有技术条件下也易于标定.同时,为了使研究结果直接用于尾气评估模型MOBILE6,对VMT又按速度和时间进行了进一步分解.由于在国内实验条件下难以收集到验证该模型所需的大量配套数据,因此,结合美国休斯顿西南地区所提供的相关交通数据对模型作了有效性检验.研究结果表明,通过该模型得到的VMT比美国EPA提供的交通流量方法(TCM)得到的值更接近实际;同时,将该模型得到的VMT输入到MOBILE6后经运算得到的尾气排放因子结果也比其使用缺省值和TCM提供值更为精确.

关键词: 车辆行驶里程, 流量预测, 指数回归, 空气质量分析 >

YU Lei, QIAO Feng-xiang, LIU Juan. VMT Estimation Model Based on Traffic Counts and Link Attributes
[J]. Journal of Transportation Systems Engineering and Information Technology, 2005, 5(1): 38-46 .

于雷,乔凤翔,刘娟 . 基于采样交通量与路段特征车辆行驶里程JVNTK估算模型
[J]. 交通运输系统工程与信息, 2005, 5(1): 38-46 .

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URL: http://www.tseit.org.cn/EN/abstract/abstract17212.shtml

http://www.tseit.org.cn/EN/Y2005/V5/I1/38

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