Airport Capacity Consequences Leveraging Aviation Integrated Modelling (ACCLAIM)

全球航空运输量以每年约5%的速度增长，这一速度通常超过了机场容量的增长。这在工业化世界尤其如此，在那里，机场扩建的经济效益越来越多地被环境问题所抵消。不受限制的运力增长将通过增加噪音和降低空气质量来影响机场周围的居民，并通过其对气候变化的贡献影响更广泛的人口。然而，限制产能增长可能会对国家和全球产生重大影响。运力限制可能会导致机票价格上涨和航空公司网络的变化，从而使过境和始发目的地的交通远离该区域，从而限制空中交通和经济的增长。伦敦就是一个热门的例子。希思罗机场的容量限制可能最终导致伦敦失去枢纽地位，这几乎肯定会给伦敦和英国整体经济带来负面的直接、间接和诱发的经济后果。因此，英国政府目前正在评估是否增加该系统的容量。许多国家都在应对这种资本密集型的机场扩容决策，不仅是在欧洲和美国，在发展中市场也越来越多。各国在经济上的得失取决于其主要机场的表现，特别是洲际中转枢纽。因此，机场容量扩建决策需要以严格的科学模型为基础，以综合的方式模拟乘客和行业行为，并说明各种选择的经济和环境影响。开发此类模式具有挑战性，因为尽管全球航空旅行预计将在未来几十年稳步增长，但随着新兴市场经济体的扩张以及新商业模式(例如联盟、低成本长途航空公司)、营销战略(例如忠诚度计划)和新技术(例如允许乘客绕过洲际枢纽的超远程飞机)的发展，全球交通分布和结构预计将发生重大变化。此外，这一变化的驱动因素(例如，未来收入和国内生产总值水平、燃料价格)以及变化本身的性质存在高度不确定性。目前用于评估机场扩建政策影响的工具有限。现有的模型(例如DFT航空模型)没有考虑到影响乘客选择机场和航空公司的一些关键因素(例如机票价格和忠诚度计划)，并且忽视了航空公司对乘客的竞争。此外，它们只以最简单的方式处理不确定性，通常使用基于情景的分析，并且不试图对系统结构的未来变化(如低成本长途航空公司的增长)进行建模。因此，我们建议开发一个适应性强、反应迅速的模型，该模型可以快速评估机场容量限制和扩建的有利和不利影响，并考虑到每个层面的不确定性。这一模式将建立在现有的AIM框架之上，并通过为面临风险的数十亿英镑投资决策提供支持，显著增加其能力。建议的方法是将作为旅行时间、票价、航空公司忠诚度、机场通道和成本的函数的旅客行程选择(包括机场和航空公司选择)的全球模型与航空公司决策模型相结合，模拟竞争条件下的航空公司票价、网络、班次和机队决策。由此产生的客流量和空中交通流量将输出到影响模块，估计气候、空气质量、噪音和经济影响。然后，将在伦敦机场容量的背景下演示该工具的应用，模拟其在国家、区域和全球范围内的影响。

Global air transport grows at around 5% per year, a rate that generally exceeds increases in airport capacity. This is especially true in the industrialized world, where the economic benefit of airport expansion has been increasingly counterbalanced by environmental concerns. Unrestricted capacity growth would impact those living around airports via increased noise and reduced air quality, and on the wider population via its contribution to climate change. However, restricting capacity growth can have significant national and global implications. Capacity constraints may lead to increases in airfares and airline network changes that take transit and origin-destination traffic away from the region, thus limiting growth in air traffic and the economy. London is a topical example. Airport capacity constraints at Heathrow may ultimately lead to a loss of London's hub status, which would almost certainly translate into negative direct, indirect and induced economic consequences for London and the UK economy as a whole. Hence, the UK Government is currently evaluating whether to add capacity to the system. Such capital-intensive airport capacity expansion decisions are being dealt with by many countries, not only in Europe and the United States, but also increasingly in developing markets. Countries stand to gain or lose economically depending on the performance of their major airports, particularly intercontinental transit hubs. Airport capacity expansion decisions therefore need to be based on rigorous scientific models that simulate passenger and industry behaviour in an integrated way, as well as illustrate the economic and environmental implications of the various options. Developing such models is challenging because, while global air travel is expected to grow steadily over the next few decades, significant changes are expected in the global distribution and structure of traffic, with the expansion of emerging market economies and the development of new business models (e.g., alliances, low-cost long-haul airlines), marketing strategies (e.g., loyalty programs) and new technology (e.g., very long-range aircraft that will allow passengers to bypass intercontinental hubs). Furthermore, there is a high degree of uncertainty in the drivers of this change (e.g., future income and GDP levels, fuel prices), as well as the nature of the change itself. The tools currently used to assess the impacts of airport expansion policies are limited. Existing models (e.g., the DfT Aviation Model) do not take into account a number of critical factors affecting passenger choice of airports and airlines (e.g. air fare and loyalty programmes), and ignore airline competition for passengers. In addition, they deal with uncertainty only in the simplest way, typically using scenario-based analysis, and do not attempt to model future changes in system structure (such as the growth of low-cost long-haul carriers). We therefore propose to develop an adaptable, responsive model, which can rapidly assess both the beneficial and undesired impacts of airport capacity constraints and expansion, accounting for uncertainty at every level. This model, ACCLAIM, would build on the existing AIM framework, and add significantly to its capabilities by providing support to the multi-billion pound investment decisions at stake. The proposed methodology is to integrate a global model of passenger itinerary choice (including airport and airline choice), as a function of travel time, fare, airline loyalty, airport access and cost, with a model of airline decision making, simulating airline fare, network, frequency and fleet decisions under competition. The resulting passenger and air traffic flows will then output to impact modules, estimating climate, air quality, noise and economic effects. Application of the tool will then be demonstrated in the context of airport capacity in London, simulating its impact on a national, regional and global scale.