Vehicle headways in urban areas
Vehicle headways in urban areas
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发表时间：
1991-10
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通讯作者：
J. Griffiths;J. Hunt
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文献类型：
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作者：
J. Griffiths;J. Hunt
大多数研究者似乎都同意，没有一个单一的分布能够充分描述车头时距分布，即使是在连续几天的同一时间同一条道路上的同一点，更不用说在不同的时间不同的道路上了。这显然是一个不满意的情况，为执业道路交通工程师。随着功能强大的个人计算机的出现，以及现在可用于微型计算机和大型计算机的复杂软件，公路工程师可以随意使用几年前还不属于他军械库的工具。然而，这种先进的技术依赖于输入适当的数据，这是本文的目的是提供一种方法，以帮助在提供相关的城市情况的车头时距数据。在英国的45个地点收集了大量与单车道交通中车辆车头时距相关的数据。这些地点位于城市地区，通常在忙碌的大街上;因此，车头时距受到诸如其他车辆的干扰、人行横道和信号交叉口的存在、停车操纵等因素的很大影响。尽管内城地区的拥堵建模现在非常流行，在这种情况下，似乎很少有关于车头时距分布的公开资料。结果发现，一个简单的分布，双位移负指数分布，提供了一个很好的适合在绝大多数网站的观察车头时距。已经描述了一种估计该分布的场地特定参数的方法，用于可以观察原始车头时距的情况。已经概述了当仅车辆流率可用时用于较不精确的参数估计的另一方法，并且已经提供了参数值的“查找”表。所选分布的另一个优点是，它可以很容易地用于绘制模拟练习中使用的样本。
Most investigators seem to agree that no single distribution will adequately describe the headway distribution even at the same point on the same road at the same time on successive days - much less at different times on different roads. This is clearly an unsatisfactory situation for the practising road traffic engineer. With the advent of powerful PCs, and with the sophisticated software now available for micro- and mainframe computers, a highway engineer has at his disposal tools which were not part of his armoury a few years ago. However, this advanced technology relies on the input of appropriate data, and it is the aim of this paper to provide a methodology to help in the provision of headway data relevant to urban situations. A large volume of data relating to headways of vehicles in single lanes of traffic was collected at 45 sites in the U.K. These sites were located in urban areas, typically in busy High Streets; consequently headways were influenced a good deal by such factors as the interference of other vehicles, by the presence of pedestrian crossings and signalised junctions, by parking manoeuvres, etc. Despite the fact that modelling of congestion in inner-city areas is now much in vogue, there appears to be little published material relating to headway distributions in this type of situation. It was found that a simple distribution, the Double Displaced Negative Exponential Distribution, provided a good fit to the observed headways at the vast majority of sites. A method of estimating site-specific parameters for this distribution has been described for the situation where it is possible to observe the raw headways. A further method has been outlined for less precise estimation of parameters when only the vehicle flow rate is available, and a 'look-up' table of parameter values has been provided. An added advantage of the distribution chosen is the ease with which it can be used for drawing samples for use in simulation exercises.