Visiting Fellowship for Juan de Dios Ortuzar

旅行需求模型用于估计人口旅行需求的变化和旅行网络的提供对旅行的数量和性质，特别是对每种现有方式的旅行的可能影响，大多数旅行需求模型是基于跨部门数据，即在一个时间观察到的数据。然而，这种类型的数据通常不会产生关于选择的令人满意的信息（即使在特定时间），因为不可能知道它们如何响应系统变化而变化。此外，很难考虑以前选择的影响。如果我们有兴趣估计未来的交通需求，这一限制尤其重要，这是城市地区长期规划的一个关键方面。面板数据，分析师在不同的时间重复采访一组人，是一个很好的选择，因为面板是专门设计的，以纳入时间效应。然而，尽管自Heckman的开创性工作以来，面板数据的使用在许多领域都有所增加，但在交通规划中的应用很少，这些应用可以分为两类：-长调查面板，其中相同的调查（即相同的设计和方法）每年重复一次或两次，持续一定数量的年，或在重要事件之前和之后。这里的主要问题是连续面板波之间的磨损（即失去受访者）。简短的调查小组：这些数据是连续两天或两天以上对同一样本进行重复测量，但随后几年不重复进行调查。最近的例子是美国国家收入动态小组研究的两天时间使用日记和德国和瑞士的六周旅行和活动日记小组。虽然损耗不是一个问题，在这里，在模式选择和低数据可变性（模式属性和个人的社会经济特征几乎是固定的）的不频繁的变化可能会导致困难估计models.When一个系统中引入了实质性的干预，数据面板有更显着的优势，用于评估变化。事实上，政策的影响可能会改变趋势，它可以更容易地捕捉这些变化使用相同的个人的观察（因为目前的行为可以解释的一部分，以前的经验）。虽然面板的优势似乎很明显，我们不知道的经验正在计划围绕系统中的一个重大变化，以估计改进模型的模式选择过程。两个值得注意的例外是在阿姆斯特丹围绕其城市高速公路系统的延伸而开发的工作和最近完成的智利圣地亚哥小组，该小组是围绕其全新的公共交通系统的实施而设计的，该系统仍然臭名昭著的Transantiago，为了制定和估计模型纳入惯性和政策冲击的影响。由于快速发展的新技术，如面板，为解决运输规划中的重要问题，需要不断更新文本，就其使用提供明确和合理的指导。此外，在重要的专业会议上介绍最新的论文将加快将得到适当支持的小组调查付诸实践，这次访问的目的是为制定和估计改进的模式选择模型的良好做法作出重大贡献，以便考虑惯性和政策冲击的影响，并将这些技术纳入广泛提供的参考和教学材料。

Travel demand models are used to estimate the likely effect of changes in the need in the population for travel and in the provision in networks for travel on the amount and nature of travel that is undertaken, and in particular on the travel that is undertaken by each of the available modes.The majority of travel demand models are based on cross-sectional data, that is, data observed at a single time. However, this type of data does not generally yield satisfactory information about choices (even at a particular time), because it is not possible to know how they would vary in response to system changes. Also, it is difficult to consider the influence of previous choices. This limitation is particularly significant if we are interested in estimating future transport demand, a key aspect in for the long-term planning of urban areas.Panel data, where the analyst interviews repeatedly a group of individuals at separate times, are a good alternative as panels are designed specifically to incorporate temporal effects. However, and although the use of panel data has increased in many areas since the pioneering work of Heckman, in transport planning there are few applications, and these can be classified in two groups:- Long survey panels, where the same survey (i.e. same design and methodology) is repeated once or twice a year for a certain number of years, or before-and-after an important event. The main problem here is attrition (i.e. loosing respondents) between successive panel waves.- Short survey panels: which consist of multi-day data where repeated measurements on the same sample are gathered over two or more successive days, but the survey is not repeated in subsequent years. Recent examples are two-day time-use diary for the US National Panel Study of Income Dynamics and six-week travel and activity diary panels in Germany and Switzerland. Although attrition is not a problem here, the infrequent changes in mode choice and low data variability (the modal attributes and the individuals socioeconomic characteristics are practically fixed) may cause difficulties in estimating models.When a substantive intervention is introduced in a system, data panels have even more significant advantages for evaluating changes. Indeed, the effects of policies could change trends, and it can be easier to capture these changes using observations for the same individuals (because part of the current behaviour could be explained by previous experience).Although the advantages of panels seem clear, we are not aware of experiences being planned around a substantial change in the system in order to estimate improved models of the mode choice process. Two notable exceptions are the work developed in Amsterdam around an extension of its urban motorway system and the recently completed Santiago Panel in Chile, which was designed around the implementation of its radically new public transport system, the still infamous Transantiago, in order to formulate and estimate models incorporating both inertia and policy shock effects.Because of the rapid development of novel techniques such as panel-based surveys to address important issues in transport planning, there is a continuing need for up to date texts providing clear and sound guidance on their use. Furthermore, the presentation of state-of-the art papers at important professional conferences will expedite the transfer of properly supported panel surveys into practice.The aims of this visit are to make a significant contribution to the establishment of good practice for the formulation and estimation of improved mode choice models, allowing to consider the effects of inertia and policy shocks, and to incorporate these techniques into widely available reference and teaching material.